View Filing Data

Weighted-average common shares outstanding, in millions:

$ 153

$ 388

$ 236

Basic

63.8

63.4

64.6

Diluted

64.5

64.2

65.4

Basic:

Income from continuing operations attributable to Cabot Corporation

$ 2.34

$ 2.87

$ 2.80

0.04

3.20

0.82

Income from continuing operations attributable to Cabot Corporation

2.38

6.07

3.62

Diluted:

2.32

2.83

2.77

0.04

3.16

0.80

Dividends per common share

2.36

5.99

3.57

$ 0.80

$ 0.76

$ 0.72

[1]	Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, the impact of the corporate adjustment for unearned revenue and Notes receivable.
[2]	Income (loss) from continuing operations before taxes for Unallocated and Other includes:

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Statement [Abstract]
Equity in earnings of affiliated companies, tax amount	$ 6	$ 5	$ 5
Income from discontinued operations, tax amount	(4)	116	29
Net income attributable to noncontrolling interests, tax amount	$ 5	$ 7	$ 4

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Amounts Reclassified Out Of Accumulated Other Comprehensive Income Loss [Abstract]
Net income	$ 160	$ 406	$ 258
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax of $(12), $2, $3	(10)	3	22
Adjustments to pension and other postretirement benefit plans, net of tax of $13, $(9), $ -	22	(17)
Net change in unrealized gain (loss) on investments, net of tax of $1, $-, $-	2	(1)	(1)
Other comprehensive income (loss)	14	(15)	21
Comprehensive income	174	391	279
Net income attributable to noncontrolling interests, net of tax of $5, $7, $4	7	18	22
Noncontrolling interests foreign currency translation adjustment	3	(1)	3
Comprehensive income attributable to noncontrolling interests	10	17	25
Comprehensive income attributable to Cabot Corporation	$ 164	$ 374	$ 254

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Amounts Reclassified Out Of Accumulated Other Comprehensive Income Loss [Abstract]
Foreign currency translation adjustment, tax	$ (12)	$ 2	$ 3
Adjustments to pension and other postretirement benefit plans, tax	13	(9)
Net change in unrealized gain (loss) on investments, tax	1
Net income attributable to noncontrolling interests, tax amount	$ 5	$ 7	$ 4

Consolidated Balance Sheets - USD ($)
$ in Millions

Sep. 30, 2013

Sep. 30, 2012

Current assets:

Cash and cash equivalents

$ 95

$ 120

Accounts and notes receivable, net of reserve for doubtful accounts of $8 and $5

634

687

Inventories

458

533

Prepaid expenses and other current assets

Notes receivable from sale of business

214

Property, plant and equipment

Total current assets

1,495

1,443

3,676

3,511

Accumulated depreciation and amortization

(2,071)

(1,959)

Notes receivable from sale of business

1,605

1,552

Goodwill

504

480

Equity affiliates

119

115

Intangible assets, net

310

330

Assets held for rent

242

Accounts payable and accrued liabilities

Other assets

Total assets

^[1]

4,233

4,399

Current liabilities:

Notes payable

264

534

606

Income taxes payable

Current portion of long-term debt

185

Total current liabilities

844

919

1,020

1,172

Commitments and contingencies (Note R)

Other liabilities

265

314

Preferred stock:

Authorized: 2,000,000 shares of $1 par value Issued and Outstanding: None and none

Common stock:

Authorized: 200,000,000 shares of $1 par value Issued: 64,223,985 and 63,600,928 shares Outstanding: 63,970,502 and 63,347,362 shares

Less cost of 253,483 and 253,565 shares of common treasury stock

(8)

Additional paid-in capital

Retained earnings

1,755

1,653

Deferred employee benefits

(2)

(8)

Accumulated other comprehensive income

103

Total Cabot Corporation stockholders' equity

1,951

1,813

Noncontrolling interests

132

126

Total stockholders' equity

2,083

1,939

Total liabilities and stockholders' equity

$ 4,233

$ 4,399

[1]	Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters' assets, and current and non-current assets held for sale.

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Statement Of Financial Position [Abstract]
Accounts and notes receivable, reserve for doubtful accounts	$ 8	$ 5
Preferred stock, authorized shares	2,000,000	2,000,000
Preferred stock, par value	$ 1	$ 1
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, authorized shares	200,000,000	200,000,000
Common stock, par value	$ 1	$ 1
Common stock, issued shares	64,223,985	63,600,928
Common stock, outstanding shares	63,970,502	63,347,362
Common treasury stock, shares	253,483	253,565

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash Flows from Operating Activities:
Net income	$ 160	$ 406	$ 258
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	190	154	142
Impairment of assets	16	2	2
Deferred tax provision	(9)	(6)	(25)
Gain on sale of business, net of tax		(191)
Loss on disposal of property, plant and equipment	2	1	2
Equity in earnings of affiliated companies	(11)	(11)	(8)
Non-cash compensation	16	18	19
Other non-cash charges (income), net		3	(3)
Changes in assets and liabilities:
Accounts and notes receivable	34	6	(111)
Inventories	64	(30)	(79)
Prepaid expenses and other current assets	5	26	(17)
Accounts payable and accrued liabilities	(18)	100	23
Income taxes payable	(29)	(13)	1
Other liabilities	(11)	(38)	(12)
Cash dividends received from equity affiliates	8	6	4
Other	2	(18)	(1)
Cash provided by operating activities	419	415	195
Cash Flows from Investing Activities:
Additions to property, plant and equipment	(264)	(281)	(230)
Proceeds from sale of business		181
Receipts from notes receivable from sale of business	39	23
Investment in equity affiliate			(2)
Acquisition of business, net of cash acquired		(1,104)
Proceeds from sales of property, plant and equipment		2	6
Increase in assets held for rent	(2)	(1)	(6)
Cash used in investing activities	(227)	(1,180)	(232)
Cash Flows from Financing Activities:
Borrowings under financing arrangements	6	84	71
Repayments under financing arrangements	(33)	(88)	(45)
Proceeds from issuance of commercial paper, net	241
Proceeds from long-term debt, net of issuance costs	117	911
Repayments of long-term debt	(442)	(172)	(21)
(Decrease) increase in notes payable, net	(12)	(42)	30
Settlement of derivatives	(31)
Proceeds from cash contributions received from noncontrolling stockholders	13	4
Purchases of common stock	(6)	(36)	(59)
Proceeds from sales of common stock	9	10	11
Cash dividends paid to noncontrolling interests	(17)	(16)	(12)
Cash dividends paid to common stockholders	(51)	(49)	(47)
Cash (used in) provided by financing activities	(206)	606	(72)
Effect of exchange rate changes on cash	(11)	(7)	8
Decrease in cash and cash equivalents	(25)	(166)	(101)
Cash and cash equivalents at beginning of year	120	286	387
Cash and cash equivalents at end of year	95	120	286
Income taxes paid	84	73	64
Interest paid	$ 51	39	34
Non-cash additions to property, plant and equipment		$ 4	$ 14

Consolidated Statement of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock, Net of Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Deferred Employee Benefits [Member]	Accumulated Other Comprehensive Income [Member]	Total Cabot Corporation Stockholders' Equity [Member]	Non-Controlling Interests [Member]
Beginning Balance at Sep. 30, 2010	$ 1,417	$ 63	$ 46	$ 1,125	$ (20)	$ 88	$ 1,302	$ 115
Beginning Balance, Shares at Sep. 30, 2010		65,370
Net income attributable to Cabot Corporation	236			236			236
Net Income attributable to non-controlling interests	22							22
Total Other comprehensive income	21					18	18	3
Noncontrolling interest-dividends	(11)							(11)
Cash dividends paid to common stockholders	(47)			(47)			(47)
Issuance of stock under employee compensation plans, net of forfeitures	8	$ 1	7				8
Issuance of stock under employee compensation plans, net of forfeitures, Shares		294
Amortization of share-based compensation	17		17				17
Purchase and retirement of common and treasury stock	(59)	$ (1)	(58)				(59)
Purchase and retirement of common and treasury stock, Shares		(1,803)
Principal payment by Employee Stock Ownership Plan under guaranteed loan	6				6		6
Notes receivable for restricted stock-payments	6		6				6
Ending Balance at Sep. 30, 2011	1,616	$ 63	18	1,314	(14)	106	1,487	129
Ending Balance, Shares at Sep. 30, 2011		63,861
Net income attributable to Cabot Corporation	388			388			388
Net Income attributable to non-controlling interests	18							18
Total Other comprehensive income	(15)					(14)	(14)	(1)
Noncontrolling interest-other	4							4
Noncontrolling interest-dividends	(24)							(24)
Cash dividends paid to common stockholders	(49)			(49)			(49)
Issuance of stock under employee compensation plans, net of forfeitures	15	$ 2	13				15
Issuance of stock under employee compensation plans, net of forfeitures, Shares		611
Amortization of share-based compensation	15		15				15
Purchase and retirement of common and treasury stock	(36)	$ (9)	(27)				(36)
Purchase and retirement of common and treasury stock, Shares		(1,124)
Principal payment by Employee Stock Ownership Plan under guaranteed loan	6				6		6
Notes receivable for restricted stock-payments	1		1				1
Ending Balance at Sep. 30, 2012	1,939	$ 56	20	1,653	(8)	92	1,813	126
Ending Balance, Shares at Sep. 30, 2012		63,348
Net income attributable to Cabot Corporation	153			153			153
Net Income attributable to non-controlling interests	7							7
Total Other comprehensive income	14					11	11	3
Contribution from noncontrolling interests	13							13
Noncontrolling interest-dividends	(17)							(17)
Cash dividends paid to common stockholders	(51)			(51)			(51)
Issuance of stock under employee compensation plans, net of forfeitures	12		12				12
Issuance of stock under employee compensation plans, net of forfeitures, Shares		784
Amortization of share-based compensation	13		13				13
Purchase and retirement of common and treasury stock	(6)		(6)				(6)
Purchase and retirement of common and treasury stock, Shares		(161)
Principal payment by Employee Stock Ownership Plan under guaranteed loan	6				6		6
Ending Balance at Sep. 30, 2013	$ 2,083	$ 56	$ 39	$ 1,755	$ (2)	$ 103	$ 1,951	$ 132
Ending Balance, Shares at Sep. 30, 2013		63,971

Significant Accounting Policies

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Significant Accounting Policies

Note A. Significant Accounting Policies

The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States. The significant accounting policies of Cabot Corporation (“Cabot” or “the Company”) are described below.

On January 20, 2012, the Company completed the sale of its Supermetals Business. The applicable results of its operations for all periods presented are reflected as discontinued operations in the Consolidated Statements of Operations. Unless otherwise indicated, all disclosures and amounts in the Notes to Consolidated Financial Statements relate to the Company’s continuing operations.

On July 31, 2012, the Company completed the acquisition of Norit N.V. (“Norit”). The financial position, results of operations and cash flows of Norit are included in the Consolidated Financial Statements from the date of acquisition.

Certain amounts in prior years’ Consolidated Statement of Cash Flows and the Consolidated Balance Sheets have been reclassified to conform to the current presentation.

Principles of Consolidation

The consolidated financial statements include the accounts of Cabot and its wholly-owned subsidiaries and majority-owned and controlled U.S. and non-U.S. subsidiaries. Additionally, Cabot considers consolidation of entities over which control is achieved through means other than voting rights, of which there were none in the periods presented. Intercompany transactions have been eliminated in consolidation.

Cash and Cash Equivalents

Cash equivalents include all highly liquid investments with a maturity of three months or less at date of acquisition. Cabot continually assesses the liquidity of cash and cash equivalents and, as of September 30, 2013, has determined that they are readily convertible to cash.

Inventories

Inventories are stated at the lower of cost or market. The cost of all carbon black inventories in the U.S. is determined using the last-in, first-out (“LIFO”) method. The cost of Specialty Fluids inventories, which are classified as assets held for rent, is determined using the average cost method. The cost of other U.S. and non-U.S. inventories is determined using the first-in, first-out (“FIFO”) method.

Cabot reviews inventory for both potential obsolescence and potential declines in anticipated selling prices. In this review, the Company makes assumptions about the future demand for and market value of the inventory, and based on these assumptions estimates the amount of any obsolete, unmarketable, slow moving or overvalued inventory. Cabot writes down the value of these inventories by an amount equal to the difference between the cost of the inventory and its estimated market value.

Investments

The Company has investments in equity affiliates and marketable securities. As circumstances warrant, all investments are subject to periodic impairment reviews. Unless consolidation is required, investments in equity affiliates, where Cabot generally owns between 20% and 50% of the affiliate, are accounted for using the equity method. Cabot records its share of the equity affiliate’s results of operations based on its percentage of ownership of the affiliate. Dividends received from equity affiliates are a return on investment and are recorded as a reduction to the equity investment value. At September 30, 2013 and 2012, Cabot had equity affiliate investments of $119 million and $115 million, respectively. Dividends declared from these investments were $8 million, $6 million and $5 million in fiscal 2013, 2012 and 2011, respectively.

All investments in marketable securities are classified as available-for-sale and are recorded at fair value with the corresponding unrealized holding gains or losses, net of taxes, recorded as a separate component of other comprehensive income within stockholders’ equity. Unrealized losses that are determined to be other-than-temporary, based on current and expected market conditions, are recognized in earnings. The fair value of marketable securities is determined based on quoted market prices at the balance sheet dates. The cost of marketable securities sold is determined by the specific identification method. The Company’s investment in marketable securities was immaterial as of both September 30, 2013 and 2012.

Property, Plant and Equipment

Property, plant and equipment are recorded at cost. Depreciation of property, plant and equipment is calculated using the straight-line method over the estimated useful lives. The depreciable lives for buildings, machinery and equipment, and other fixed assets are twenty to twenty-five years, ten to twenty-five years, and three to twenty-five years, respectively. The cost and accumulated depreciation for property, plant and equipment sold, retired, or otherwise disposed of are removed from the Consolidated Balance Sheets and resulting gains or losses are included in earnings in the Consolidated Statements of Operations. Expenditures for repairs and maintenance are charged to expenses as incurred. Expenditures for major renewals and betterments, which significantly extend the useful lives of existing plant and equipment, are capitalized and depreciated.

In the third quarter of fiscal 2013, the Company changed the estimated depreciable lives of certain machinery and equipment from ten to twenty-five years to reflect the Company’s experience. The change was accounted for as a change in estimate. Based on the asset base at the time of the change, the Company expects the change will increase Income from continuing operations by $9 million ($0.14 per diluted common share) over a twelve month period. The change increased Income from continuing operations by $4 million ($0.06 per diluted common share) in fiscal 2013.

Cabot capitalizes interest costs when they are part of the historical cost of acquiring and constructing certain assets that require a period of time to prepare for their intended use. During fiscal 2013, 2012 and 2011, Cabot capitalized $5 million, $4 million and $2 million of interest costs, respectively. These amounts will be amortized over the life of the related assets.

Intangible Assets and Goodwill

The Company records tangible and intangible assets acquired and liabilities assumed in business combinations under the acquisition method of accounting. Amounts paid for an acquisition are allocated to the assets acquired and liabilities assumed based on their fair values at the date of acquisition. Goodwill is comprised of the purchase price of business acquisitions in excess of the fair value assigned to the net tangible and identifiable intangible assets acquired. Goodwill is not amortized but is reviewed for impairment annually, or when events or changes in the business environment indicate that the carrying value of the reporting unit may exceed its fair value. A reporting unit, for the purpose of the impairment test, is at or below the operating segment level, and constitutes a business for which discrete financial information is available and regularly reviewed by segment management. The separate businesses included within Performance Materials and Advanced Technologies are considered separate reporting units. Goodwill balances relative to these segments are recorded in the Fumed Metal Oxides reporting unit within Performance Materials and the Security Materials reporting unit within Advanced Technologies.

The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value amount and as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. Alternatively, the Company may elect to proceed directly to the two-step goodwill impairment test. If an initial qualitative assessment identifies that it is more likely than not that the carrying value of a reporting unit exceeds its estimated fair value, an additional quantitative evaluation is performed under the two-step impairment test. If based on the quantitative evaluation the fair value of the reporting unit is less than its carrying amount, the Company performs an analysis of the fair value of all assets and liabilities of the reporting unit. If the implied fair value of the reporting unit’s goodwill is determined to be less than its carrying amount, an impairment is recognized for the difference. The fair value of a reporting unit is based on discounted estimated future cash flows. The assumptions used to estimate fair value include management’s estimates of future growth rates, operating cash flows, capital expenditures, and discount rates over an estimate of the remaining operating period at the reporting unit level. Should the fair value of any of our reporting units decline because of reduced operating performance, market declines, or other indicators of impairment, or as a result of changes in the discount rate, charges for impairment may be necessary. The future growth in the Purification Solutions business, which had $466 million of goodwill at September 30, 2013, is highly dependent on the growth in the mercury removal portion of this business. This growth relies upon the adoption and enforcement of environmental laws and regulations, particularly those that would require U.S. based coal fired electrical utilities to reduce the quantity of air pollutants they release, including mercury, to comply with the Mercury and Air Toxics Standards that become effective in April 2015. The annual review is performed as of May 31.

The Company uses assumptions and estimates in determining the fair value of assets acquired and liabilities assumed in a business combination. The determination of the fair value of intangible assets requires the use of significant judgment with regard to (i) assumptions used in the valuation model; and (ii) determination of the intangible assets’ useful lives. The Company estimates the fair value of identifiable acquisition-related intangible assets principally based on projections of cash flows that will arise from these assets. The projected cash flows are discounted to determine the fair value of the assets at the dates of acquisition. The Company reviews definite-lived intangible assets for impairment when indication of potential impairment exists, such as a significant reduction in cash flows associated with the assets. Actual cash flows arising from a particular intangible asset could vary from projected cash flows which could imply different carrying values from those established at the dates of acquisition and which could result in impairment of such asset. The Company evaluates indefinite-lived intangible assets for impairment annually or when events occur or circumstances change that may reduce the fair value of the asset below its carrying amount. The annual review is performed as of May 31. The Company may first perform a qualitative assessment to determine whether it is necessary to perform the quantitative impairment test or bypass the qualitative assessment and proceed directly to performing the quantitative impairment test. The quantitative impairment test is based on discounted estimated future cash flows. The assumptions used to estimate fair value include management’s estimates of future growth rates and discount rates over an estimate of the remaining operating period at the unit of accounting level. The Company’s intangible assets are primarily comprised of trademarks, customer relationships, patented and unpatented technology and other intellectual property. Finite lived intangible assets are amortized over their estimated useful lives.

Assets Held for Rent

Assets held for rent represent Specialty Fluids cesium formate product that is available to customers in the normal course of business. Assets held for rent are stated at average cost.

Asset Retirement Obligations

Cabot estimates incremental costs for special handling, removal and disposal of materials that may or will give rise to conditional asset retirement obligations (“ARO”) and then discounts the expected costs back to the current year using a credit adjusted risk free rate. Cabot recognizes ARO liabilities and costs when the timing and/or settlement can be reasonably estimated. The ARO reserves were $16 million and $18 million at September 30, 2013 and 2012, respectively. In fiscal 2012, the Company assumed asset retirement obligations of $10 million in the acquisition of Norit and made changes to its cash flow estimates for its other ARO resulting in an additional liability of $1 million. In fiscal 2013, ARO liabilities were reduced by $2 million mainly due to changes made to the Company’s cash flow timing estimates.

Impairment of Long-Lived Assets

Cabot’s long-lived assets primarily include property, plant and equipment, long-term investments, assets held for rent and sale. The carrying values of long-lived assets are reviewed for impairment whenever events or changes in business circumstances indicate that the carrying amount of an asset may not be recoverable. An asset impairment is recognized when the carrying value of the asset is not recoverable based on the probability-weighted undiscounted estimated future cash flows to be generated by the asset. Cabot’s estimates reflect management’s assumptions about selling prices, production and sales volumes, costs and market conditions over an estimate of the remaining operating period. If an impairment is indicated, the asset is written down to fair value. If the asset does not have a readily determinable market value, a discounted cash flow model may be used to determine the fair value of the asset. The key inputs to the discounted cash flow would be the same as the undiscounted cash flow noted above, with the addition of the discount rate used. In circumstances when an asset does not have separate identifiable cash flows, an impairment charge is recorded when Cabot no longer intends to use the asset.

To test for impairment of assets we generally use a probability-weighted estimate of the future undiscounted net cash flows of the assets over their remaining lives to determine if the value of the asset is recoverable. Long-lived assets are grouped with other assets and liabilities at the lowest level for which independent identifiable cash flows are determinable.

Foreign Currency Translation

The functional currency of the majority of Cabot’s foreign subsidiaries is the local currency in which the subsidiary operates. Assets and liabilities of foreign subsidiaries are translated into U.S. dollars at exchange rates in effect at the balance sheet dates. Income and expense items are translated at average monthly exchange rates during the year. Unrealized currency translation adjustments are included as a separate component of Accumulated other comprehensive income within stockholders’ equity.

Realized and unrealized foreign currency gains and losses arising from transactions denominated in currencies other than the subsidiary’s functional currency are reflected in earnings with the exception of (i) intercompany transactions considered to be of a long-term investment nature; and (ii) foreign currency borrowings designated as net investment hedges. Gains or losses arising from these transactions are included as a component of other comprehensive income. In fiscal 2013, 2012 and 2011, net foreign currency transaction gains of $2 million, losses of $2 million, and losses of $6 million, respectively, are included in Other expense in the Consolidated Statements of Operations as part of continuing operations.

Financial Instruments

Cabot’s financial instruments consist primarily of cash and cash equivalents, accounts and notes receivable, investments, notes receivable from the sale of a business, accounts payable and accrued liabilities, short-term and long-term debt, and derivative instruments. The carrying values of Cabot’s financial instruments approximate fair value with the exception of long-term debt that has not been designated as part of a fair value hedge and note receivable from the sale of a business (refer to Note J). The non-hedged long-term debt is recorded at amortized cost. The fair values of the Company’s financial instruments are based on quoted market prices, if such prices are available. In situations where quoted market prices are not available, the Company relies on valuation models to derive fair value. Such valuation takes into account the ability of the financial counterparty to perform.

Cabot uses derivative financial instruments primarily for purposes of hedging exposures to fluctuations in interest rates and foreign currency exchange rates, which exist as part of its on-going business operations. Cabot does not enter into derivative contracts for speculative purposes, nor does it hold or issue any derivative contracts for trading purposes. All derivatives are recognized on the Consolidated Balance Sheets at fair value. Where Cabot has a legal right to offset derivative settlements under a master netting agreement with a counterparty, derivatives with that counterparty are presented on a net basis. The changes in the fair value of derivatives are recorded in either earnings or Accumulated other comprehensive income, depending on whether or not the instrument is designated as part of a hedge transaction and, if designated as part of a hedge transaction, the type of hedge transaction. The gains or losses on derivative instruments reported in Accumulated other comprehensive income are reclassified to earnings in the period in which earnings are affected by the underlying hedged item. The ineffective portion of all hedges is recognized in earnings during the period in which the ineffectiveness occurs.

In accordance with Cabot’s risk management strategy, the Company may enter into certain derivative instruments that may not be designated as hedges for hedge accounting purposes. Although these derivatives are not designated as hedges, the Company believes that such instruments are closely correlated with the underlying exposure, thus managing the associated risk. The Company records in earnings the gains or losses from changes in the fair value of derivative instruments that are not designated as hedges. Cash movements associated with these instruments are presented in the Consolidated Statement of Cash Flows as Cash Flows from Operating Activities because the derivatives are designed to mitigate risk to the Company’s cash flow from operations. The cash flows related to the principal of these instruments are presented in the Cash Flows from Financing Activities section of the Consolidated Statement of Cash Flows.

Revenue Recognition

Cabot recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the price is fixed or determinable and collectability is reasonably assured. Cabot generally is able to ensure that products meet customer specifications prior to shipment. If the Company is unable to determine that the product has met the specified objective criteria prior to shipment or if title has not transferred because of sales terms, the revenue is considered “unearned” and is deferred until the revenue recognition criteria are met.

Shipping and handling charges related to sales transactions are recorded as sales revenue when billed to customers or included in the sales price.

The following table shows the relative size of the revenue recognized in each of the Company’s reportable segments:


	Years ended September 30
	2013			2012			2011
Reinforcement Materials		56	%		63	%		65%
Performance Materials		27	%		28	%		29%
Advanced Technologies		7	%		7	%		6%
Purification Solutions		10	%		2	%⁽¹⁾		N/A

⁽¹⁾	Fiscal 2012 includes two months of revenue for Purification Solutions, which the Company acquired on July 31, 2012.

Cabot derives the substantial majority of its revenues from the sale of products in Reinforcement Materials and Performance Materials. Revenue from these products is typically recognized when the product is shipped and title and risk of loss have passed to the customer. The Company offers certain of its customers cash discounts and volume rebates as sales incentives. The discounts and volume rebates are recorded as a reduction in sales at the time revenue is recognized and are estimated based on historical experience and contractual obligations. Cabot periodically reviews the assumptions underlying its estimates of discounts and volume rebates and adjusts its revenues accordingly.

Revenue in Advanced Technologies, excluding the Specialty Fluids Business, is typically recognized when the product is shipped and title and risk of loss have passed to the customer. Depending on the nature of the contract with the customer, a portion of the revenue may be recognized using proportional performance. The Company has technology and licensing agreements with one customer that are accounted for as multiple element arrangements. Revenue is recognized ratably over the term of the agreements limited by the cumulative amounts that become due, some of which are through 2022. The Company recorded $9 million of royalty and technology payments in fiscal year 2013 from these agreements.

A significant portion of the revenue in the Specialty Fluids Business, included in Advanced Technologies, arises from the rental of cesium formate. This revenue is recognized throughout the rental period based on the contracted rental terms. Customers are also billed and revenue is recognized, typically at the end of the job, for cesium formate product that is not returned. The Company also generates revenues from cesium formate sold outside of a rental process and revenue is recognized upon delivery of the fluid.

Revenue in Purification Solutions is typically recognized when the product is shipped and title and risk of loss have passed to the customer. For major activated carbon injection systems projects, revenue is recognized using the percentage-of-completion method.

Cost of Sales

Cost of sales consists of cost of raw and packaging materials, direct manufacturing costs, depreciation, internal transfer costs, inspection costs, inbound and outbound freight and shipping and handling costs, plant purchasing and receiving costs and other overhead expense necessary to manufacture the products.

Accounts and Notes Receivable

Trade receivables are recorded at the invoiced amount and generally do not bear interest. Trade receivables in China may at certain times be settled with the receipt of bank issued non-interest bearing notes, which represent the Company’s notes receivable balance. These notes totaled 148 million Chinese Renminbi (“RMB”) ($24 million) and 155 million RMB ($24 million) as of September 30, 2013 and 2012, respectively, and are included in accounts and notes receivable. Cabot periodically sells a portion of the trade receivables in China at a discount and such sales are accounted for as asset sales. The Company does not have any continuing involvement with the notes after the sale. The difference between the proceeds from the sale and the carrying value of the receivables is recognized as a loss on the sale of receivables and is included in Other expense in the accompanying Consolidated Statements of Operations. During fiscal 2013, 2012 and 2011, the Company recorded charges of $4 million, $2 million, and less than $1 million, respectively, for the sale of these receivables.

Cabot maintains allowances for doubtful accounts based on an assessment of the collectability of specific customer accounts, the aging of accounts receivable and other economic information on both a historical and prospective basis. Customer account balances are charged against the allowance when it is probable the receivable will not be recovered. The change from fiscal 2012 to 2013 was $3 million due to an increase in specific customer reserves. The change from fiscal 2011 to 2012 was immaterial. There is no off-balance sheet credit exposure related to customer receivable balances.

Notes receivable from sale of business

The Company’s Notes receivable from sale of business are derived from the sale of the Supermetals Business to Global Advanced Metals Pty Ltd., an Australian company (“GAM”) as discussed in Note D. The Notes are carried at amortized cost and the carrying value was $214 and $252 million at September 30, 2013 and 2012, respectively. The outstanding amount due and payable under these Notes on March 31, 2014 is $215 million. The Notes are subject to an impairment assessment and impairment is recorded if, based on current information, it is probable that the Company will be unable to collect all amounts due from the borrower in accordance with the terms of the Notes. No impairment was recorded as of September 30, 2013 and 2012.

Stock-based Compensation

Cabot recognizes compensation expense for stock-based awards granted to employees using the fair value method. Under the fair value recognition provisions, stock-based compensation cost is measured at the grant date based on the fair value of the award, and is recognized as expense over the service period, which generally represents the vesting period, and includes an estimate of the awards that will be forfeited, and an estimate of what level of performance the Company will achieve for Cabot’s performance-based stock awards. Cabot calculates the fair value of its stock options using the Black-Scholes option pricing model. The fair value of restricted stock and restricted stock units is determined using the closing price of Cabot stock on the day of the grant.

Selling and Administrative Expenses

Selling and administrative expenses consist of salaries and fringe benefits of sales and office personnel, general office expenses and other expenses not directly related to manufacturing operations.

Research and Technical Expenses

Research and technical expenses include salaries, equipment and material expenditures, and contractor fees and are expensed as incurred.

Income Taxes

Deferred income taxes are determined based on the estimated future tax effects of differences between financial statement carrying amounts and the tax bases of existing assets and liabilities. Deferred tax assets are recognized to the extent that realization of those assets is considered to be more likely than not.

A valuation allowance is established for deferred taxes when it is more likely than not that all or a portion of the deferred tax assets will not be realized. Provisions are made for the U.S. income tax liability and additional non-U.S. taxes on the undistributed earnings of non-U.S. subsidiaries, except for amounts Cabot has designated to be indefinitely reinvested.

Cabot records benefits for uncertain tax positions based on an assessment of whether the position is more likely than not to be sustained by the taxing authorities. If this threshold is not met, no tax benefit of the uncertain tax position is recognized. If the threshold is met, the tax benefit that is recognized is the largest amount that is greater than 50% likely of being realized upon ultimate settlement. This analysis presumes the taxing authorities’ full knowledge of the positions taken and all relevant facts, but does not consider the time value of money. The Company also accrues for interest and penalties on its uncertain tax positions and includes such charges in its income tax provision in the Consolidated Statements of Operations.

Accumulated Other Comprehensive Income

Accumulated other comprehensive income, which is included as a component of stockholders’ equity, includes unrealized gains or losses on available-for-sale marketable securities and derivative instruments, currency translation adjustments in foreign subsidiaries, translation adjustments on foreign equity securities and minimum pension liability adjustments.

Accumulated other comprehensive items in the accompanying balance sheet consist of the following items net of tax:


	Year ended September 30			Year ended September 30
	2013			2012
	(In millions)			(In millions)
Foreign currency translation adjustment at beginning of year	$	167		$	163
Net foreign currency translation adjustments		(13	)		4

Balance at end of year	$	154		$	167

Unrealized gain on investments and derivative instruments at beginning of year		—		$	1
Net unrealized gains		2			(1	)

Balance at end of year	$	2		$	—

Pension and other postretirement benefit plans at beginning of year		(75	)	$	(58	)
Net change in pension and other postretirement benefit plans		22			(17	)

Balance at end of year	$	(53	)	$	(75	)

Total accumulated other comprehensive income	$	103		$	92

Environmental Costs

Cabot accrues environmental costs when it is probable that a liability has been incurred and the amount can be reasonably estimated. When a single liability amount cannot be reasonably estimated, but a range can be reasonably estimated, Cabot accrues the amount that reflects the best estimate within that range or the low end of the range if no estimate within the range is better. The amount accrued reflects Cabot’s assumptions about remediation requirements at the contaminated site, the nature of the remedy, the outcome of discussions with regulatory agencies and other potentially responsible parties at multi-party sites, and the number and financial viability of other potentially responsible parties. Cabot discounts certain of its long-term environmental liabilities to reflect the time value of money if the amount of the liability and the amount and timing of cash payments for the liability are fixed and reliably determinable. The liability will be discounted at a rate that will produce an amount at which the liability theoretically could be settled in an arm’s length transaction with a third party. This discounted rate may not exceed the risk-free rate for maturities comparable to those of the liability. Cabot does not reduce its estimated liability for possible recoveries from insurance carriers. Proceeds from insurance carriers are recorded when realized by either the receipt of cash or a contractual agreement.

Use of Estimates

The preparation of consolidated financial statements in conformity with generally accepted accounting principles in the United States requires management to make certain estimates and assumptions that affect the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates.

Recent Accounting Pronouncements	12 Months Ended
Recent Accounting Pronouncements	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	Note B. Recent Accounting Pronouncements In the first quarter of fiscal 2013, the Company adopted guidance that resulted in the addition of separate, consolidated statements of comprehensive income.

Tabular disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22580-107794

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Direct Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6510796

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Indirect Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6515603

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6372559&loc=d3e765-108305

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accounting Change
-URI http://asc.fasb.org/extlink&oid=6503790

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22499-107794

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.10-01.(b)(6))
-URI http://asc.fasb.org/extlink&oid=27015980&loc=d3e46468-122699

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=28359718&loc=d3e22583-107794

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6507316

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6372559&loc=d3e725-108305

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Retrospective Application
-URI http://asc.fasb.org/extlink&oid=6523989

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 01
-Paragraph b
-Subparagraph 6
-Article 10

Discontinued Operations And Disposal Groups [Abstract]

Acquisitions

12 Months Ended

Sep. 30, 2013

Business Combinations [Abstract]

Acquisitions

Note C. Acquisitions

Acquisition of Norit

On July 31, 2012, Cabot acquired all the issued and outstanding shares of Norit N.V. (“Norit”) for approximately $1.1 billion in cash. Norit develops, manufactures and sells activated carbon products and related delivery systems used in a range of applications, including air and water purification, food and beverages, pharmaceuticals and catalysts. The results of Norit’s operations are reported under the Purification Solutions reportable segment.

As of June 2013, the Company completed the valuation of its assets acquired and liabilities assumed. The allocation of the purchase price is based on the fair value of assets acquired and liabilities assumed as of July 31, 2012. During fiscal 2013, the Company recorded certain measurement period adjustments which are presented in the table below. The measurement period adjustments and the related tax impact were immaterial to the Company’s consolidated financial statements. Accordingly, the effects have not been retrospectively applied. The following table presents the components and allocation of the purchase price, including the measurement period adjustments:


	At Acquisition Date (As reported at September 30, 2012)			Measurement Period Adjustments			At Acquisition Date (As adjusted at September 30, 2013)
	(Dollars in millions)
Current assets	$	207		$	(4	)	$	203
Property, plant and equipment		385			(14	)		371
Other non-current assets		72			4			76
Intangible assets		325			(8	)		317
Goodwill		432			22			454
Current liabilities		(98	)		—			(98	)
Deferred non-current tax liabilities		(176	)		4			(172	)
Other non-current liabilities		(34	)		(4	)		(38	)

Total purchase price	$	1,113		$	—		$	1,113

As part of the purchase price allocation, the Company determined that the separately identifiable intangible assets were customer relationships, developed technology, and trademarks in the amounts of $110 million, $150 million, and $57 million, respectively. Customer relationships and developed technology are being amortized over a weighted average period of 18 years and 20 years, respectively. Trademarks are considered to have an indefinite life and will be tested for impairment annually or when events or changes in the business environment indicate that the carrying value of the intangible assets may exceed their fair value.

The determination of the fair value of intangible assets acquired required the use of significant judgment with regard to (i) assumptions used in the valuation model; and (ii) determination of the intangible assets’ useful lives. The Company estimated the fair value of identifiable acquisition-related intangible assets principally based on projections of cash flows that will arise from these assets. The projected cash flows were discounted to determine the fair value of the assets at the date of acquisition.

The fair value of the assets acquired includes trade receivables of $46 million. The Company did not acquire any other class of receivable when it acquired Norit.

The excess of the purchase price over the fair value of the tangible net assets and intangible assets acquired was recorded as goodwill. The goodwill recognized is attributable to the expected growth and operating synergies that the Company expects to realize from this acquisition. Goodwill from the acquisition will not be deductible for tax purposes.

The following table provides pro forma net sales and earnings for fiscal 2012, as if Norit had been acquired on October 1, 2011. The unaudited pro forma results reflect certain adjustments related to the acquisition, such as increased depreciation and amortization expense on assets acquired from Norit resulting from recording the fair value of assets acquired, the impact of acquisition financing with the related tax effects. The pro forma results do not include any synergies or other effects of the planned integration of Norit. Accordingly, such pro forma amounts are not necessarily indicative of the results that actually would have occurred had the acquisition been completed on October 1, 2011, nor are they indicative of the future operating results of the combined company.


	Year ended September 30
	2012 (unaudited)
	(in millions)
Net sales	$	3,585
Income from continuing operations		209

Acquisition of Nhumo

In June 2013, the Company entered into a stock purchase agreement with Grupo Kuo S.A.B. de C.V. (“KUO”) to purchase the remaining 60 percent common stock equity of its Mexican carbon black manufacturing joint venture, Nhumo, S.A.P.I. de C.V. (“NHUMO”). On November 15, 2013, the Company completed the acquisition and paid KUO approximately $80 million in cash. In addition, NHUMO issued $25 million of redeemable preferred stock to KUO. The preferred stock will accumulate dividends at 6% annually, which will be payable annually, and will be redeemable at the option of KUO or the Company on the fifth anniversary of the closing for $25 million. The Company’s preexisting interest in NHUMO will be re-measured to its fair value at the date of acquisition and a gain will be recorded if the fair value is greater than the carrying amount.

Discontinued Operations

12 Months Ended

Sep. 30, 2013

Discontinued Operations

Note D. Discontinued Operations

In January 2012, the Company sold its Supermetals Business to Global Advanced Metals Pty Ltd., an Australian company (“GAM”), for $452 million, including cash consideration of $175 million received on the closing date and notes receivable (“GAM Notes”) totaling $277 million payable at various dates through March 2014. In addition, the Company is entitled to receive quarterly cash payments in each calendar quarter that the GAM Notes are outstanding in an amount equal to 50% of cumulative year to date adjusted earnings before interest, taxes, depreciation and amortization (“Adjusted EBITDA”) of the sold business for the relevant calendar quarter. A minimum payment of $11.5 million was guaranteed in the first year after the sale regardless of the Adjusted EBITDA generated and is included in the $277 million total of GAM Notes. The carrying value of the GAM Notes at September 30, 2013 is $214 million, which is presented as Notes receivable from sale of business on the Consolidated Balance Sheet. These Notes are secured by liens on the property and assets of the sold business and guaranteed by the GAM Corporate Group. The Notes are included in Current assets as they are due no later than March 31, 2014. Through September 30, 2013, Cabot received payments of $62 million under the GAM Notes.

The after-tax gain from discontinued operations of $2 million for fiscal 2013 primarily relates to tax adjustments of $4 million partially off-set by $2 million of loss from the settlement of pension liabilities of the disposed business. Discontinued Operations, net of tax in fiscal 2012 includes the after-tax gain on the sale of the Supermetals Business of $191 million. Discontinued Operations, net of tax in fiscal 2012 and 2011 also include results of the Supermetal Business prior to sale. The operating results of the Supermetals Business prior to the sale and the gain on the sale of the business are reported within Income from discontinued operations, net of tax, in the Consolidated Statements of Operations.

The following table summarizes the results from discontinued operations:


	Years Ended September 30
	2013			2012			2011
	(Dollars in millions)
Net sales and other operating revenues	$	—		$	46		$	201

Income from operations before income taxes		—			21			84
Provision for income taxes on operations		—			(7	)		(31	)

Income from operations, net of tax	$	—		$	14		$	53

(Loss) Gain on sale of discontinued operations		(2	)		300			—
Benefit from (Provision for) income taxes on gain (loss) on sale		4			(109	)		—

Gain on sale of discontinued operations, net of tax		2			191			—

Income from discontinued operations, net of tax	$	2		$	205		$	53

Discontinued Operations—Other

In addition to the divesture of its Supermetals Business, the Company also has classified certain settlements associated with other businesses divested as part of Income from discontinued operations, net of tax in its Consolidated Statements of Operations for the fiscal years ended September 30, 2013 and 2011. These settlements resulted in gains of less than $1 million in fiscal 2013 and losses of less than $1 million in fiscal 2011. No such charges were recorded in fiscal 2012.

In connection with the sale of the Supermetals Business, the Company and GAM entered into a tantalum ore supply agreement under which the Company agreed to sell to GAM all of the tantalum ore mined at the Company’s mine in Manitoba, Canada, subject to a maximum amount, for a three-year period commencing in calendar year 2013. In March 2013, the Company and GAM agreed to terminate the agreement and the Company expects to ship the remaining tantalum ore inventory it has on hand to GAM by the end of calendar 2013. Revenues, costs and expenses from this agreement for the year ended September 30, 2013 are included in continuing operations of the Specialty Fluids Business.

The entire disclosure for the facts and circumstances leading to the completed or expected disposal, manner and timing of disposal, the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the segment in which the disposal group was reported, and the classification (whether sold or classified as held for sale) and carrying value of the assets and liabilities comprising the disposal group. Includes all disposal groups, including those classified as components of the entity (discontinued operations).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1436-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1474-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1510-107760

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1020-107759

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1012-107759

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2443-110228

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2941-110230

Property Plant And Equipment [Abstract]

Inventories

12 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Inventories

Note E. Inventories

Inventories, net of LIFO, obsolete, unmarketable and slow moving reserves, are as follows:


	September 30
	2013		2012
	(Dollars in millions)
Raw materials	$	102	$	131
Work in process		2		5
Finished goods		310		351
Other		44		46

Total	$	458	$	533

Inventories valued under the LIFO method comprised approximately 5% of total inventories at September 30, 2013 and 2012. At September 30, 2013 and 2012, the LIFO reserve was $55 million and $52 million, respectively. Other inventory is comprised of certain spare parts and supplies.

During fiscal 2013 and 2012, inventory quantities carried on a LIFO basis were reduced at the Company’s U.S. carbon black sites. These reductions led to liquidations of LIFO inventory quantities and resulted in a decrease of cost of goods sold of $1 million and an increase in consolidated net income of $1 million ($0.01 per diluted common share) in both fiscal 2013 and 2012. No such reductions occurred in fiscal 2011.

Cabot reviews inventory for both potential obsolescence and potential loss of value periodically. In this review, Cabot makes assumptions about the future demand for and market value of the inventory and, based on these assumptions, estimates the amount of obsolete, unmarketable or slow moving inventory. The inventory reserves were $15 million at both September 30, 2013 and 2012.

Property, Plant and Equipment

12 Months Ended

Sep. 30, 2013

Property, Plant and Equipment

Note F. Property, Plant and Equipment

Property, plant and equipment is summarized as follows:


	September 30
	2013			2012
	(Dollars in millions)
Land and land improvements	$	138		$	167
Buildings		511			495
Machinery and equipment		2,511			2,379
Other		238			226
Construction in progress		278			244

Total property, plant and equipment		3,676			3,511
Less: accumulated depreciation		(2,071	)		(1,959	)

Net property, plant and equipment	$	1,605		$	1,552

Depreciation expense was $176 million, $153 million and $138 million for fiscal 2013, 2012 and 2011, respectively.

Goodwill and Other Intangible Assets

12 Months Ended

Sep. 30, 2013

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

Note G. Goodwill and Other Intangible Assets

Cabot had goodwill balances of $504 million and $480 million at September 30, 2013 and 2012, respectively. The carrying amount of goodwill attributable to each reportable segment with goodwill balances and the changes in those balances during the years ended September 30, 2013 and 2012 are as follows:


	Reinforcement Materials			Performance Materials		Advanced Technologies		Purification Solutions		Total
	(Dollars in millions)
Balance at September 30, 2011	$	27		$	11	$	2	$	—	$	40
Goodwill acquired		—			—		—		432		432
Foreign currency translation adjustment		1			—		—		7		8

Balance at September 30, 2012		28			11		2		439		480
Measurement period adjustments⁽¹⁾		—			—		—		22		22
Foreign currency translation adjustment		(3	)		—		—		5		2

Balance at September 30, 2013	$	25		$	11	$	2	$	466	$	504

⁽¹⁾	Refer to Note C for further details related to the measurement period adjustments.

Goodwill impairment tests are performed at least annually. The Company performed its annual impairment assessment as of May 31, 2013 and determined there was no impairment.

The following table provides information regarding the Company’s intangible assets:


	Years Ended September 30
	2013							2012
	Gross Carrying Value		Accumulated Amortization			Net Intangible Assets		Gross Carrying Value		Accumulated Amortization			Net Intangible Assets
	(Dollars in millions)
Intangible assets with finite lives
Developed technology	$	155	$	(9	)	$	146	$	151	$	(2	)	$	149
Customer relationships⁽¹⁾		113		(7	)		106		121		(1	)		120
Other intangible assets		3		(2	)		1		6		(3	)		3

Total intangible assets, finite lives	$	271	$	(18	)	$	253	$	278	$	(6	)	$	272
Trademarks, indefinite lives		57		—			57		58		—			58

Total intangible assets	$	328	$	(18	)	$	310	$	336	$	(6	)	$	330

⁽¹⁾	The change in the gross carrying value of the Customer relationships intangible asset is primarily due to measurement period adjustments as described in Note C.

Intangible assets with finite lives are amortized over their estimated useful lives, which range from six to twenty years, with a weighted average amortization period of 19 years. See Note C for weighted average lives of intangible assets acquired in the acquisition of Norit. Amortization expense for the years ended September 30, 2013 and 2012 was $14 million and $3 million, respectively, and is included in Cost of sales and Selling and administrative expenses in the Consolidated Statements of Operations. Amortization expense for the year ended September 30, 2011 was less than $1 million and is included in Cost of sales in the Consolidated Statements of Operations. Total amortization expense is estimated to be approximately $14 million each year for the next five fiscal years. Intangible assets with indefinite lives are evaluated for impairment at least annually. The Company performed its annual impairment assessment as of May 31, 2013, and determined there was no impairment.

Accounts Payable, Accrued Liabilities and Other Liabilities

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Accounts Payable, Accrued Liabilities and Other Liabilities

12 Months Ended

Sep. 30, 2013

Payables And Accruals [Abstract]

Note H. Accounts Payable, Accrued Liabilities and Other Liabilities

Accounts payable and accrued liabilities included in current liabilities consist of the following:


	September 30
	2013		2012
	(Dollars in millions)
Accounts payable	$	398	$	425
Accrued employee compensation		41		46
Other accrued liabilities		95		135

Total	$	534	$	606

Other long-term liabilities consist of the following:


	September 30
	2013		2012
	(Dollars in millions)
Employee benefit plan liabilities	$	149	$	190
Non-current tax liabilities		47		53
Financial instrument liabilities		—		26
Other accrued liabilities		69		45

Total	$	265	$	314

Debt and Other Obligations

12 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Debt and Other Obligations

Note I. Debt and Other Obligations

Long-term Obligations

The Company’s long-term obligations, the fiscal year in which they mature and their respective interest rates are summarized below:


	September 30
	2013			2012
	(Dollars in millions)
Variable Rate Debt:
$750 million Revolving Credit Facility, expires 2016	$	—		$	189
Chinese Renminbi Notes, due through 2016, 5.40%—6.77%		47			11

Total variable rate debt		47			200
Fixed Rate Debt:
5% Notes due 2017	$	300		$	300
2.55% Notes due 2018		250			250
3.7% Notes due 2022		350			350
Medium Term Notes:
Notes due 2019, 7.42%		30			30
Notes due 2022, 8.346%—8.47%		15			15
Note due 2028, 6.57%—7.28%		8			8

Total Medium Term Notes	$	53		$	53
Eurobond, due 2013, 5.25%		—			177
ESOP Note, due 2014, 8.29%		2			8
Chinese Renminbi Notes, due through 2018, 4.68%—6.65%		16			5

Total fixed rate debt		971			1,143
Capital lease obligations, due through 2031		18			16
Unamortized debt discount		(2	)		(2	)

Total debt		1,034			1,357
Less current portion of long-term debt		(14	)		(185	)

Total long-term debt	$	1,020		$	1,172

$750 million Revolving Credit Facility—The Company has a $750 million committed unsecured revolving credit agreement which expires in August 2016. All borrowings under the credit agreement are based on variable interest rates. Generally, the interest rates are based on LIBOR plus a spread. This spread, which was 1.125% as of September 30, 2013, is based on the Company’s credit rating, resulting in a total interest rate of 1.304% as of September 30, 2013. The Company plans to use the credit agreement for general corporate purposes, which may include working capital, refinancing existing indebtedness, capital expenditures, share repurchases, and acquisitions, and support for the commercial paper program. The credit agreement contains affirmative, negative and financial covenants and events of default customary for financings of this type. The financial covenants in the credit agreement include interest coverage, debt-to-EBITDA and subsidiary debt to total capitalization ratios. As of September 30, 2013, no amounts were outstanding on this facility. The amount available on the revolving credit agreement, after consideration of letters of credit and commercial paper outstanding, was $508 million as of September 30, 2013.

Chinese Renminbi Debt—The Company’s consolidated Chinese subsidiaries had $63 million and $16 million of unsecured long-term debt outstanding as of September 30, 2013 and September 30, 2012, respectively. The increase relates to the financing of the rubber blacks manufacturing facility in Xingtai City, Hebei Province, China.

5% Notes due fiscal 2017— In fiscal 2009, Cabot issued $300 million in public notes with a coupon of 5% that will mature on October 1, 2016. These notes are unsecured and pay interest on April 1 and October 1. The net proceeds of this offering were $296 million after deducting discounts and issuance costs. The discount of approximately $2 million was recorded at issuance and is being amortized over the life of the notes.

2.55% Notes due fiscal 2018—In July 2012, Cabot issued $250 million in public notes with a coupon of 2.55% that will mature on January 15, 2018. These notes are unsecured and pay interest on January 15 and July 15. The net proceeds of this offering were $248 million after deducting discounts and issuance costs. The discount of less than $1 million was recorded at issuance and is being amortized over the life of the notes.

3.7% Notes due fiscal 2022—In July 2012, Cabot issued $350 million in public notes with a coupon of 3.7% that will mature on July 15, 2022. These notes are unsecured and pay interest on January 15 and July 15. The net proceeds of this offering were $347 million after deducting discounts and issuance costs. The discount of less than $1 million was recorded at issuance and is being amortized over the life of the notes.

Medium Term Notes—At both September 30, 2013 and 2012, there were $53 million of unsecured medium term notes outstanding issued to numerous lenders with various fixed interest rates and maturity dates. The weighted average maturity of the total outstanding medium term notes is 8 years with a weighted average interest rate of 7.65%.

Eurobond—A European subsidiary issued an unsecured $175 million U.S. dollar denominated bond with a fixed coupon rate of 5.25% in fiscal 2003 with interest due on March 1 and September 1 of each year. The functional currency of this subsidiary is the Euro. A discount of approximately $1 million was recorded at issuance and was amortized over the life of the bond. A portion of the Eurobond was designated as a fair value hedge and accordingly was recorded at fair value. As described in Note K, the Company entered into cross-currency swaps and a variable interest rate swap to hedge the variability in cash flows for changes in the exchange rates and to offset a portion of the changes in the fair value of the underlying debt. The bond, and associated derivatives, matured and were repaid in September 2013.

ESOP Debt—In November 1988, Cabot’s Employee Stock Ownership Plan (“ESOP”) borrowed $75 million from an institutional lender in order to finance its purchase of Cabot shares. This debt bears interest at 8.29% per annum and is to be repaid in quarterly installments through December 31, 2013. Cabot, as guarantor, has reflected the outstanding balance of $2 million and $8 million at September 30, 2013 and 2012, respectively. An equal amount, representing deferred employee benefits, has been recorded as a reduction to stockholders’ equity. Cabot contributed $4 million to the ESOP to service the debt during fiscal 2013, $5 million during fiscal 2012, and $4 million during fiscal 2011. Dividends on ESOP shares used for debt service were $2 million for each of fiscal years 2013, 2012 and 2011. In addition, interest incurred on the ESOP debt was less than $1 million during fiscal 2013 and $1 million during both fiscal 2012 and 2011.

Capital Lease Obligations— Cabot had capital lease obligations for certain equipment and buildings with a recorded value of $18 million and $16 million at September 30, 2013 and 2012, respectively. Cabot will make payments totaling $42 million over the next 18 years, including $12 million of imputed interest. At September 30, 2013 and 2012, the original cost of capital lease assets was $24 million and $26 million, respectively, and the associated accumulated depreciation of assets under capital leases was $9 million and $11 million at September 30, 2013 and 2012, respectively. The amortization related to those assets under capital lease is included in depreciation expense.

Future Years Payment Schedule

The aggregate principal amounts of long-term debt and capital lease obligations due in each of the five years from fiscal 2014 through 2018 are as follows:


Fiscal Years Ending	Principal payments on long term debt		Payments on Capital Lease Obligations			Total
	(Dollars in millions)
2014	$	12	$	5		$	17
2015		30		4			34
2016		11		3			14
2017		300		3			303
2018		262		3			265
Thereafter		403		24			427
Less: executory costs and interest		—		(24	)		(24	)

Total	$	1,018	$	18		$	1,036

Standby letters of credit—At September 30, 2013, the Company had provided standby letters of credit that were outstanding and not drawn totaling $10 million, which expire through fiscal 2014.

Short Term Obligations

Short-term Notes Payable —The Company had unsecured short-term notes of $264 million and $62 million as of September 30, 2013 and 2012, respectively, with maturities of less than one year. The weighted-average interest rate on short-term notes payable, including commercial paper, was 0.7% and 5.2% for fiscal 2013 and 2012, respectively.

In January 2013, Cabot entered into agreements to initiate a commercial paper program under which Cabot may issue unsecured commercial paper. The maximum aggregate balance of commercial paper and the revolving credit facility may not exceed the current maximum size of the revolving credit facility, $750 million. The proceeds from the issuance of the commercial paper have been used for general corporate purposes, which may include working capital, refinancing existing indebtedness, capital expenditures, share repurchases, and acquisitions. The revolving credit facility is available to repay the outstanding commercial paper, if necessary. The commercial paper will typically be sold at a discount from par at rates that will vary based upon market conditions at the time of the issuance of the commercial paper. The maturities of the commercial paper will vary but may not exceed 364 days from the date of issue. The definitive documents relating to the Program contain customary representations, warranties, default and indemnification provisions.

The outstanding balance of commercial paper included within the $264 million Notes payable on the Consolidated Balance Sheets as of September 30, 2013 was $241 million, bearing a weighted-average interest rate of 0.32% with a weighted-average maturity of 28 days.

Financial Instruments and Fair Value Measurements

12 Months Ended

Sep. 30, 2013

Text Block [Abstract]

Financial Instruments and Fair Value Measurements

Note J. Financial Instruments and Fair Value Measurements

The FASB authoritative guidance on fair value measurements defines fair value, provides a framework, for measuring fair value in generally accepted accounting principles, and requires certain disclosures about fair value measurements. The disclosures focus on the inputs used to measure fair value. The guidance establishes the following hierarchy for categorizing these inputs:

There were no transfers of financial assets or liabilities measured at fair value between Level 1 and Level 2, or transfers into or out of Level 3, during fiscal 2013 or 2012.

The GAM Notes are classified as Level 3 instruments within the fair value hierarchy because they are valued using a valuation model with significant unobservable inputs. The valuation model used is the discounted cash flow model and the significant inputs are the discount rate which incorporates the credit standing of GAM and the fact that the notes are secured by liens on the property and assets of the sold business and guaranteed by the GAM Corporate Group, Adjusted EBITDA forecast and timing of expected cash flows from GAM. The notes are carried at amortized cost and the carrying value was $214 million at September 30, 2013 which is lower than the contractually due payment of $215 million on March 31, 2014. As of September 30, 2012 the carrying value and fair value of GAM Notes were both $252 million. Using the discounted cash flow model at September 30, 2013 with the main inputs being the discount rate and the timing of the contractually due payments of $215 million on March 31, 2014, the fair value of the notes was $205 million.

The following table presents information about the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2013 and 2012. The derivatives presented in the table below are presented by derivative type, net of the legal right to offset derivative settlements by each counterparty:


	September 30
	2013		2012
	Level 2		Level 2
	(Dollars in Millions)
Assets at fair value:
Guaranteed investment contract⁽¹⁾	$	14	$	14
Derivatives relating to interest rates⁽²⁾		—		2

Total assets at fair value	$	14	$	16

Liabilities at fair value:
Derivatives relating to foreign currency⁽²⁾	$	—	$	28
Hedged long-term debt⁽³⁾		—		36

Total liabilities at fair value	$	—	$	64

⁽¹⁾	Included in “Other assets” in the Consolidated Balance Sheets.

⁽²⁾	Included in “Prepaid expenses and other current assets”, “Other assets”, “Accounts payable and accrued liabilities” or “Other liabilities” in the Consolidated Balance Sheets.

⁽³⁾	Included in “Current portion of long-term debt” in the fiscal 2012 Consolidated Balance Sheets.

At September 30, 2013 and 2012, the fair values of cash and cash equivalents, accounts and notes receivable, accounts payable and accrued liabilities, and notes payable approximated their carrying values due to the short-term nature of these instruments. The carrying value and fair value of the long-term fixed rate debt were $0.97 billion and $1.01 billion, respectively, as of September 30, 2013. The carrying value and fair value of the long-term fixed rate debt were $1.14 billion and $1.42 billion, respectively, as of September 30, 2012. The fair values of Cabot’s fixed rate long-term debt and capital lease obligations are estimated based on comparable quoted market prices at the respective period ends. The carrying amounts of Cabot’s floating rate long-term debt and capital lease obligations approximate their fair values. All such measurements are based on observable inputs and are classified as Level 2 within the fair value hierarchy. The valuation technique used is the discounted cash flow model.

Derivatives

12 Months Ended

Sep. 30, 2013

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivatives

Note K. Derivatives

Risk Management

Cabot’s business operations are exposed to changes in interest rates, foreign currency exchange rates and commodity prices because Cabot finances certain operations through long and short-term borrowings, denominates transactions in a variety of foreign currencies and purchases certain commoditized raw materials. Changes in these rates and prices may have an impact on future cash flows and earnings. The Company manages these risks through normal operating and financing activities and, when deemed appropriate, through the use of derivative financial instruments.

The Company has policies governing the use of derivative instruments and does not enter into financial instruments for trading or speculative purposes.

By using derivative instruments, Cabot is subject to credit and market risk. If a counterparty fails to fulfill its performance obligations under a derivative contract, Cabot’s credit risk will equal the fair value of the derivative. Generally, when the fair value of a derivative contract is positive, the counterparty owes Cabot, thus creating a payment risk for Cabot. The Company minimizes counterparty credit (or repayment) risk by entering into transactions with major financial institutions of investment grade credit rating. As of September 30, 2013, the counterparties with which the Company has executed derivatives carried a Standard and Poor’s credit rating between A and AA-, inclusive. Cabot’s exposure to market risk is not hedged in a manner that completely eliminates the effects of changing market conditions on earnings or cash flow. No significant concentration of credit risk associated with our derivative instruments existed at September 30, 2013.

Interest Rate Risk Management

Cabot’s objective is to maintain a certain fixed-to-variable interest rate mix on the Company’s debt obligations. Cabot periodically enters into interest rate swaps as a hedge of the underlying debt instruments to effectively change the characteristics of the interest rate without changing the debt instrument. The following table provides details of the derivatives held as of September 30, 2012 to manage interest rate risk. As of September 30, 2013, there were no derivatives held to manage interest rate risk.


		Notional Amount
Description	Borrowing	September 30, 2013	September 30, 2012	Hedge Designation
Interest Rate Swap—Fixed to Variable⁽¹⁾	Eurobond (20% of $175 million)	—	USD 35 million	Fair Value

⁽¹⁾	In September 2013, the Company settled the Eurobond and related foreign currency and interest rate swaps.

Foreign Currency Risk Management

Cabot’s international operations are subject to certain risks, including currency exchange rate fluctuations and government actions. Cabot endeavors to match the currency in which debt is issued to the currency of the Company’s major, stable cash receipts. In some situations Cabot has issued debt denominated in U.S. dollars and then entered into cross currency swaps that exchange the dollar principal and interest payments into a currency where the Company expects long-term, stable cash receipts.

Additionally, the Company has foreign currency exposure arising from its net investments in foreign operations. Cabot, from time to time, enters into cross-currency swaps to mitigate the impact of currency rate changes on the Company’s net investments.

The Company also has foreign currency exposure arising from the denomination of monetary assets and liabilities in foreign currencies other than the functional currency of a given subsidiary as well as the risk that currency fluctuations could affect the dollar value of future cash flows generated in foreign currencies. Accordingly, Cabot uses short-term forward contracts to minimize the exposure to foreign currency risk.

In certain situations where the Company has forecasted purchases under a long-term commitment or forecasted sales denominated in a foreign currency, Cabot may enter into appropriate financial instruments in accordance with the Company’s risk management policy to hedge future cash flow exposures.

The following table provides details of the derivatives held as of September 30, 2013 and 2012 to manage foreign currency risk.


Description	Borrowing	Notional Amount		Hedge Designation
Description	Borrowing	September 30, 2013	September 30, 2012	Hedge Designation
Cross Currency Swap	Eurobond (80% of $175 million)	—	USD 140 million swapped to EUR 124 million	No designation

Cross Currency Swap	Eurobond (20% of $175 million)	—	USD 35 million swapped to EUR 31 million	No designation

Forward Foreign Currency Contracts⁽¹⁾	N/A	USD 31 million	USD 106 million	No designation

Forward Foreign Currency Contracts⁽¹⁾	N/A	—	USD 3 million	Cash Flow

⁽¹⁾	Cabot’s forward foreign exchange contracts are denominated primarily in the Australian dollar, British pound sterling, Canadian dollar, Chinese renminbi, Czech koruna, Euro, Indian rupee and Japanese yen.

Accounting for Derivative Instruments and Hedging Activities

The Company determines the fair value of financial instruments using quoted market prices whenever available. When quoted market prices are not available for various types of financial instruments (such as forwards, options and swaps), the Company uses standard models with market-based inputs, which take into account the present value of estimated future cash flows and the ability of the financial counterparty to perform. For interest rate and cross-currency swaps, the significant inputs to these models are interest rate curves for discounting future cash flows. For forward foreign currency contracts, the significant inputs are interest rate curves for discounting future cash flows, and exchange rate curves of the foreign currency for translating future cash flows.

Fair Value Hedge

For derivative instruments that are designated and qualify as fair value hedges, the gain or loss on the derivative as well as the offsetting gain or loss on the hedged item attributable to the hedged risk are recognized in current period earnings.

Cash Flow Hedge

For derivative instruments that are designated and qualify as cash flow hedges, the effective portion of the gain or loss on the derivative is recorded in Accumulated other comprehensive income and reclassified to earnings in the same period or periods during which the hedged transaction affects earnings. Gains and losses on the derivative representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current period earnings.

Other Derivative Instruments

From time to time, the Company may enter into certain derivative instruments that may not be designated as hedges for accounting purposes, which include cross currency swaps, foreign currency forward contracts and commodity derivatives. For cross currency swaps and foreign currency forward contracts not designated as hedges, the Company uses standard models with market-based inputs. The significant inputs to these models are interest rate curves for discounting future cash flows, and exchange rate curves of the foreign currency for translating future cash flows. In determining the fair value of the commodity derivatives, the significant inputs to valuation models are quoted market prices of similar instruments in active markets. Although these derivatives do not qualify for hedge accounting, Cabot believes that such instruments are closely correlated with the underlying exposure, thus managing the associated risk. The gains or losses from changes in the fair value of derivative instruments that are not accounted for as hedges are recognized in current period earnings.

During fiscal 2013, 2012, and 2011, for derivatives designated as hedges, the change in unrealized gains in Accumulated other comprehensive income, the hedge ineffectiveness recognized in earnings, the realized gains or losses reclassified from Accumulated other comprehensive income, and the losses reclassified from Accumulated other comprehensive income to earnings were immaterial.

During fiscal 2013 and 2012, a gain of $4 million and a loss of $10 million, respectively, were recognized in earnings as a result of the remeasurement to Euros of the $175 million bond held by one of Cabot’s European subsidiaries. Both the gain and loss were recognized in earnings through Other expense within the Consolidated Statement of Operations. The 2013 gain was offset by a loss of $2 million and the 2012 loss was offset by a gain of $12 million, both from Cabot’s cross currency swaps that are not designated as hedges, but which Cabot entered into to offset the foreign currency remeasurement exposure on the debt. Additionally, during fiscal 2013 and 2012, Cabot recognized in earnings through Other expense within the Consolidated Statement of Operations, gains of $5 million and $10 million respectively, related to its foreign currency forward contracts, which were not designated as hedges.

During fiscal 2011, a loss of $2 million was recognized in earnings as a result of the remeasurement to Euros of the $175 million bond held by one of Cabot’s European subsidiaries. This loss, which was recognized in earnings through Other expense within the Consolidated Statement of Operations, was offset by a gain of $1 million from Cabot’s cross currency swaps that are not designated as hedges, but which Cabot entered into to offset the foreign currency translation exposure on the debt. Additionally, during fiscal 2011, Cabot recognized in earnings through Other expense within the Consolidated Statement of Operations, gains of $3 million related to its foreign currency forward contracts, which were not designated as hedges.

The following table provides the fair value and Consolidated Balance Sheets presentations of derivative instruments by each derivative type, without regard to the legal right to offset derivative settlement by each counterparty:


Fair Value of Derivative Instruments	Consolidated Balance Sheet Caption	September 30, 2013		September 30, 2012
		(Dollars in millions)
Asset Derivatives
Derivatives designated as hedges Interest rate⁽¹⁾	Accounts payable and accrued liabilities	$	—	$	2

Derivatives not designated as hedges Other⁽²⁾	Prepaid expenses and other current assets		—		1

Total Asset Derivatives		$	—	$	3

Liability Derivatives
Derivatives not designated as hedges Foreign currency⁽¹⁾	Accounts payable and accrued liabilities, and Other liabilities	$	—	$	28
Other⁽²⁾	Prepaid expenses and other current assets		—		1

Total derivatives not designated as hedges		$	—	$	29

Total Liability Derivatives		$	—	$	29

⁽¹⁾

Contracts of $2 million presented on a gross basis in this table at September 30, 2012 have the legal right to offset against other types of contracts with a common counterparty and, therefore, are presented on a net basis in “Accounts payable and accrued liabilities” in the Consolidated Balance Sheet.

⁽²⁾	Contracts in an asset and liability position presented on a gross basis in fiscal 2012 in this table have the legal right of offset and, therefore, are presented on a net basis in “Prepaid expenses and other current assets” in the Consolidated Balance Sheets.

The net after-tax amounts to be reclassified from Accumulated other comprehensive income to earnings within the next 12 months are expected to be immaterial.

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41620-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579240-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624177-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80784-113994

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41641-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5708775-113959

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5708773-113959

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41635-113959

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4E
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624181-113959

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41638-113959

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Compensation And Retirement Disclosure [Abstract]

Venezuela	12 Months Ended
Venezuela	Sep. 30, 2013
Equity Method Investments And Joint Ventures [Abstract]
Venezuela	Note L. Venezuela Cabot owns 49% of an operating affiliate in Venezuela, which is accounted for as an equity affiliate, through wholly owned subsidiaries that carry the investment and receive its dividends. As of September 30, 2013, these subsidiaries carried the operating affiliate investment of $25 million and held 20 million bolivars ($3 million) in cash. In February 2013, the Venezuelan government announced a devaluation of the bolivar from 4.3 bolivars to the U.S. dollar (B/$) to 6.3 B/$. Accordingly, the Company remeasured the bolivar denominated monetary accounts in its wholly owned subsidiaries at the new rate, resulting in the recognition of a $2 million loss in the second quarter of fiscal 2013 through other expense within the Consolidated Statements of Operations. In fiscal 2013, the Company recognized a tax benefit of $1 million from a reduction in the deferred tax liability due to the impact of the devaluation of the bolivar on unremitted earnings. The operating affiliate recognized a $1 million loss during fiscal 2013 as a result of the remeasurement of monetary assets and liabilities in bolivars and a charge of $1 million from the tax impact of the currency devaluation mainly on U.S. dollar and Euro denominated cash and receivable balances. Cabot’s share of these combined losses was approximately $1 million, which was included within the Equity in earnings of affiliated companies, net of tax line of the Consolidated Statements of Operations for fiscal 2013. As a result of the currency devaluation, the Company performed an impairment analysis on its equity investment in Venezuela during the second quarter of fiscal 2013 using the discounted cash flow model to determine the fair value of its investment. The Company determined that there was no impairment to the carrying value of its equity investment. The Company continues to closely monitor developments in Venezuela and their potential impact on the recoverability of its equity affiliate investment. During fiscal 2013 and 2012, the operating affiliate declared dividends of 15 million bolivars ($3 million) and 27 million bolivars ($6 million), respectively, to the Company’s wholly owned subsidiaries, which were paid in U.S. dollars and repatriated. The Venezuelan bolivars held by the Company’s wholly owned subsidiaries may only be exchanged for foreign currencies through certain Venezuelan government controlled channels. The channels available are the Venezuelan central bank (“CADIVI”), and Venezuelan government and government-backed bond offerings. The bond offerings use a bidding process, where companies and individuals requiring U.S. dollars place a request for a fixed sum, and CADIVI then determines how to allocate the pool of U.S. dollars in that issuance. The Company closely monitors its ability to convert its bolivar holdings into U.S. dollars, as the Company intends to convert substantially all bolivars held by its wholly owned subsidiaries in Venezuela to U.S. dollars as soon as practical. Any future change in the CADIVI official rate or opening of additional parallel markets could lead the Company to change the exchange rate and result in gains or losses on the bolivar denominated assets held by its wholly owned subsidiaries and operating affiliate.

Employee Benefit Plans

12 Months Ended

Sep. 30, 2013

Employee Benefit Plans

Note M. Employee Benefit Plans

The information below provides detail concerning the Company’s benefit obligations under the defined benefit and post-retirement benefit plans it sponsors, including the obligations the Company assumed in its acquisition of Norit. The information included in this footnote and the related tables also includes amounts pertaining to the Company’s former Supermetals Business, unless indicated otherwise.

Defined benefit plans provide pre-determined benefits to employees that are distributed upon retirement. Cabot used a September 30 measurement date for all U.S. and foreign plan obligations and assets in both fiscal 2013 and 2012. Cabot is making all required contributions to these plans. The accumulated benefit obligation was $170 million for the U.S. defined benefit plans and $412 million for the foreign plans as of September 30, 2013 and $187 million for the U.S. defined benefit plans and $398 million for the foreign plans as of September 30, 2012.

In addition to benefits provided under the defined benefit and post-retirement benefit plans, the Company provides benefits under defined contribution plans. One of these plans includes an Employee Stock Ownership Plan (“ESOP”) component, which is described below. Excluding the expenses related to the ESOP, Cabot recognized expenses related to these plans of $9 million in fiscal 2013, $7 million in fiscal 2012 and $7 million in fiscal 2011.

Employee Stock Ownership Plan

Eligible employees of Cabot and its participating subsidiaries in the U.S. participate in the ESOP. Under the ESOP, which is 100% Company funded, 108,696.645 shares of Cabot common stock are allocated to participants’ accounts at the end of each quarter. Cabot has established a minimum and maximum contribution percentage of total eligible pay. The actual contribution percentage in any given quarter varies depending on Cabot’s stock price on the last day of the relevant quarter, the total eligible compensation and the amount of the dividends allocated to participants. Compensation expense related to the ESOP based on the fair value of the shares on the date of allocation was $4 million in fiscal 2013, $5 million in fiscal 2012 and $4 million in fiscal 2011. At December 31, 2013, all shares available for distribution under the ESOP will have been allocated to participant accounts and no further contributions under the plan will be made after that date.

The following provides information about benefit obligations, plan assets, the funded status and weighted-average assumptions of the defined benefit pension and postretirement benefit plans:


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Change in Benefit Obligations:
Benefit obligation at beginning of year	$	195		$	423		$	147		$	236		$	64		$	18		$	64		$	15
Service cost		6			9			5			7			—			—			1			—
Interest cost		6			15			7			11			2			1			2			1
Plan participants’ contribution		—			2			—			1			—			—			—			—
Foreign currency exchange rate changes		—			—			—			5			—			(1	)		—			1
(Gain) loss from changes in actuarial assumptions		(19	)⁽¹⁾		12			12			38			(6	)		—			1			2
Benefits paid⁽²⁾		(11	)		(17	)		(11	)		(11	)		(5	)		(1	)		(5	)		(1	)
Settlements or curtailment gain		(7	)		(2	)		(1	)		(4	)		—			—			(1	)		—
Acquisition of Norit		—			—			36			140			—			—			2			—
Divestiture of CSM		—			(5	)		—			—			—			—			—			—
Other		—			2			—			(1	)		—			—			—			—

Benefit obligation at end of year	$	170		$	439		$	195		$	422		$	55		$	17		$	64		$	18


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Change in Plan Assets:
Fair value of plan assets at beginning of year	$	149		$	356		$	103		$	197		$	—		$	—		$	—		$	—
Actual return on plan assets		17			22			23			24			—			—			—			—
Employer contribution		—			13			8			13			5			—			5			1
Plan participants’ contribution		—			2			—			1			—			—			—			—
Foreign currency exchange rate changes		—			4			—			5			—			—			—			—
Benefits paid⁽²⁾		(10	)		(17	)		(11	)		(11	)		(5	)		—			(5	)		(1	)
Settlements		—			(1	)		—			(5	)		—			—			—			—
Acquisition of Norit		—			—			27			133			—			—			—			—
Divestiture of Supermetals Business		—			(3	)		—			—			—			—			—			—
Expenses paid from assets		(1	)		(1	)		(1	)		(1	)		—			—			—			—

Fair value of plan assets at end of year	$	155		$	375		$	149		$	356		$	—		$	—		$	—		$	—

Funded status	$	(15	)	$	(64	)	$	(46	)	$	(66	)	$	(55	)	$	(17	)	$	(64	)	$	(18	)

Recognized liability	$	(15	)	$	(64	)	$	(46	)	$	(66	)	$	(55	)	$	(17	)	$	(64	)	$	(18	)

(1)

During fiscal 2013, the Company approved the freezing of U.S. pension plans that resulted in the remeasurement of the plans assets and liabilities. The remeasurement decreased the net pension obligation of the plan, which is included within Other Liabilities caption on the Consolidated Balance Sheets, by $19 million and increased Accumulated other comprehensive income by $13 million, net of tax. The impact to the Company’s Net periodic benefit cost was less than $1 million.

(2)	Included in this amount is $7 million that the Company paid directly to the participants in its defined benefit plans in both fiscal 2013 and 2012.

Pension Assumptions and Strategy

The following assumptions were used to determine the pension benefit obligations at September 30:


	Assumptions as of September 30
	2013						2012						2011
	Pension Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
Actuarial assumptions as of the year-end measurement date:
Discount rate		4.5	%		3.8	%		3.5	%		3.6	%		4.5	%		4.8	%
Rate of increase in compensation		3.0	%		3.1	%		3.5	%		3.1	%		3.8	%		3.1	%
Actuarial assumptions used to determine net periodic benefit cost during the year:
Discount rate		3.5	%		3.6	%		4.5	%		4.8	%		4.5	%		4.3	%
Expected long-term rate of return on plan assets		7.8	%		5.3	%		7.8	%		5.3	%		7.8	%		6.1	%
Rate of increase in compensation		3.5	%		3.1	%		3.8	%		3.2	%		3.8	%		3.3	%

Post Retirement Assumptions and Strategy

The following assumptions were used to determine the post retirement benefit obligations at September 30:


	Assumptions as of September 30
	2013						2012						2011
	Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
Actuarial assumptions as of the year-end measurement date:
Discount rate		4.0	%		4.4	%		3.3	%		3.9	%		4.5	%		4.9	%
Initial health care cost trend rate		7.5	%		7.5	%		8.0	%		7.4	%		8.5	%		8.0	%
Actuarial assumptions used to determine net cost during the year:
Discount rate		3.3	%		3.9	%		4.5	%		4.9	%		4.5	%		4.8	%
Initial health care cost trend rate		8.0	%		7.4	%		8.5	%		7.9	%		7.5	%		8.0	%

Cabot uses discount rates as of September 30, the plans’ measurement date, to determine future benefit obligations under its U.S. and foreign defined benefit plans. The discount rates for the defined benefit plans in the U.S., Canada, UAE, Euro-zone, Japan, Switzerland and the U.K. are derived from yield curves that reflect high quality corporate bond yield or swap rate information in each region and reflect the characteristics of Cabot’s employee benefit plans. The discount rates for the defined benefit plans in the Czech Republic and Indonesia are based on government bond indices that best reflect the durations of the plans, adjusted for credit spreads presented in selected AA corporate bond indices. The rates utilized are selected because they represent long-term, high quality, fixed income benchmarks that approximate the long-term nature of Cabot’s pension obligations and related payouts.


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Net Amounts Recognized in the Consolidated Balance Sheets
Noncurrent assets	$	—		$	4		$	—		$	4		$	—		$	—		$	—		$	—
Current liabilities		—			(1	)		—			(1	)		(5	)		—			(6	)		(1	)
Noncurrent liabilities		(15	)		(67	)		(46	)		(69	)		(50	)		(17	)		(58	)		(17	)

Amounts recognized in Accumulated other comprehensive income at September 30, 2013 and 2012 were as follows:


	Years Ended September 30
	2013					2012				2013					2012
	Pension Benefits									Postretirement Benefits
	U.S.			Foreign		U.S.		Foreign		U.S.			Foreign		U.S.			Foreign
	(Dollars in millions)
Net actuarial (gain) loss	$	(4	)	$	78	$	29	$	77	$	(3	)	$	3	$	3		$	3
Net prior service cost (credit)		—			—		1		—		(7	)		—		(10	)		—

Balance in accumulated other comprehensive income, pretax	$	(4	)	$	78	$	30	$	77	$	(10	)	$	3	$	(7	)	$	3

In fiscal 2014, an estimated net loss of $3 million will be amortized from Accumulated other comprehensive income to net periodic benefit cost. In addition, amortization of estimated prior service credits of $3 million for other postretirement benefits will be amortized from accumulated other comprehensive income to net periodic benefit costs in fiscal 2014.

Estimated Future Benefit Payments

The Company expects that the following benefit payments will be made to plan participants in the years from 2014 to 2023:


	Pension Benefits				Postretirement Benefits
	U.S.		Foreign		U.S.		Foreign
	(Dollars in millions)
Years Ended:
2014	$	12	$	16	$	5	$	1
2015		11		17		5		1
2016		14		20		5		1
2017		13		19		5		1
2018		12		20		5		1
2019-2023		60		117		20		5

Post retirement medical benefits are unfunded and impact Cabot’s cash flows as benefits become due. The Company expects to contribute $3 million and $13 million related to its U.S. and foreign pension plans, respectively, in fiscal 2014.

Net periodic defined benefit pension and other postretirement benefit costs include the following components:


	Years Ended September 30
	2013						2012						2011						2013					2012					2011
	Pension Benefits																		Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign		U.S.			Foreign		U.S.			Foreign
	(Dollars in millions)
Service cost	$	6		$	9		$	5		$	7		$	5		$	6		$	—		$	—	$	1		$	—	$	1		$	—
Interest cost		6			15			7			11			6			11			2			1		2			1		2			1
Expected return on plan assets		(10	)		(18	)		(9	)		(13	)		(8	)		(13	)		—			—		—			—		—			—
Amortization of prior service cost		—			—			—			—			—			—			(3	)		—		(3	)		—		(3	)		—
Net losses		1			4			1			3			—			3			—			—		—			—		—			—
Settlements or curtailments cost (income)		1			2			1			1			—			—			—			—		(1	)		—		—			—
Other		—			—			—			—			—			2			—			—		—			—		—			—

Net periodic benefit cost	$	4		$	12		$	5		$	9		$	3		$	9		$	(1	)	$	1	$	(1	)	$	1	$	—		$	1

Other changes in plan assets and benefit obligations recognized in other comprehensive income, pre-tax are as follows:


	Years Ended September 30
	2013						2012						2011					2013					2012				2011
	Pension Benefits																	Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.		Foreign			U.S.			Foreign		U.S.		Foreign		U.S.			Foreign
	(Dollars in millions)
Net (gains) losses	$	(32	)	$	8		$	(3	)	$	27		$	2	$	1		$	(6	)	$	—	$	1	$	1	$	(1	)	$	(1	)
Prior service cost		—			—			(1	)		—			—		—			3			—		1		—		(2	)		—
Amortization of prior service (cost) credit		—			—			—			—			—		—			—			—		3		—		4			—
Amortization of prior unrecognized loss		(2	)		(4	)		(1	)		(3	)		—		(3	)		—			—		—		—		—			—
Other		—			(4	)		—			1			—		—			—			—		—		—		—			—

Total other comprehensive (income) loss	$	(34	)	$	—		$	(5	)	$	25		$	2	$	(2	)	$	(3	)	$	—	$	5	$	1	$	1		$	(1	)

Curtailments and settlements of employee benefit plans

In recent years, the Company incurred curtailments and settlements of certain of its employee benefit plans. Associated with these curtailments and settlements, the Company recognized a net loss of $3 million , a net loss of $1 million and a net gain of less than $1 million in fiscal 2013, 2012 and 2011, respectively.

Sensitivity Analysis

Measurement of postretirement benefit expense is based on actuarial assumptions used to value the postretirement benefit liability at the beginning of the year. Assumed health care cost trend rates have an effect on the amounts reported for the health care plans. The fiscal 2013 weighted-average assumed health care cost trend rate is 8.0% for U.S. plans and 7.4% for foreign plans. The ultimate weighted-average health care cost trend rate has been designated as 7.5% for U.S. plans and 7.0% for foreign plans and is anticipated to be achieved during 2018 and 2016, respectively. A one percentage point change in the 2013 assumed health care cost trend rate would have the following effects:


	1-Percentage-Point
	Increase				Decrease
	U.S.		Foreign		U.S.		Foreign
	(Dollars in millions)
Effect on postretirement benefit obligation	$	—	$	3	$	—	$	(2	)

Plan Assets

The Company’s defined benefit pension plans weighted-average asset allocations at September 30, 2013 and 2012, by asset category are as follows:


	Pension Assets
	September 30
	2013						2012
	U.S.			Foreign			U.S.			Foreign
Asset Category:
Equity securities		63	%		41	%		62	%		39	%
Debt securities		37	%		54	%		38	%		56	%
Cash and other securities		—			5	%		—			5	%

Total		100	%		100	%		100	%		100	%

To develop the expected long-term rate of return on plan assets assumption, the Company used a capital asset pricing model. The model considers the current level of expected returns on risk-free investments comprised of government bonds, the historical level of the risk premium associated with the other asset classes in which the portfolio is invested, and the expectations for future returns for each asset class. The expected return for each asset class was then weighted based on the target asset allocation to develop the expected long-term rate of return for each plan.

Cabot’s investment strategy for each of its defined benefit plans in the U.S. and abroad is generally based on a set of investment objectives and policies that cover time horizons and risk tolerance levels consistent with plan liabilities. Periodic studies are performed to determine the asset mix that will meet pension obligations at a reasonable cost to the Company. The assets of the defined benefit plans are comprised principally of investments in equity and high quality fixed income securities, which are broadly diversified across the capitalization and style spectrum and are managed using both active and passive strategies. The weighted average target asset allocation for the U.S. plans is 65% in equity and 35% in fixed income and for the foreign plans is 39% in equity, 55% in fixed income, 2% in real estate and 4% in cash and other securities.

For pension or other postretirement benefit plan assets classified as Level 1 measurements (measured using quoted prices in active markets), total fair value is either the price of the most recent trade at the time of the market close or the official close price, as defined by the exchange on which the asset is most actively traded on the last trading day of the period, multiplied by the number of units held without consideration of transaction costs.

For pension or other postretirement benefit plan assets classified as Level 2 measurements, where the security is frequently traded in less active markets, fair value is based on the closing price at the end of the period; where the security is less frequently traded, fair value is based on the price a dealer would pay for the security or similar securities, adjusted for any terms specific to that asset or liability. Market inputs are obtained from well-established and recognized vendors of market data and subjected to tolerance/quality checks.

Some pension or other postretirement benefit plan assets are held in funds where a net asset value is calculated based on the fair value of the underlying assets and the number of shares owned. The classification of the fund (Level 1, 2 or 3 measurements) is determined based on the classification of the significant holdings within the fund.

The fair value of the Company’s pension plan assets at September 30, 2013 and 2012 by asset category is as follows:


	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)
	2013				Total		2012				Total
Asset Category:
Cash	$	2	$	1	$	3	$	4	$	1	$	5
Direct investments:				—
U.S. equity securities		21		—		21		19		—		19
Non-U.S. equity securities		—		—		—		5		—		5
Non-U.S. government bonds		52		—		52		50		—		50
Non-U.S. corporate bonds		—		—		—		11		—		11

Total direct investments	$	73	$	—	$	73	$	85	$	—	$	85
Investment funds:
Equity funds⁽¹⁾		132		101		233		97		108		205
Fixed income funds⁽²⁾		93		111		204		66		126		192
Real estate funds⁽³⁾		—		1		1		—		2		2
Common and collective investment trust funds⁽⁴⁾		—		1		1		—		—		—
Money market funds		3		—		3		1		—		1
Other		—		—		—		4		—		4

Total investment funds	$	228	$	214	$	442	$	168	$	236	$	404
Alternative investments:
Insurance contracts⁽⁵⁾		—		12		12		—		10		10
Other		—		—		—		—		1		1

Total alternative investments		—	$	12	$	12	$	—	$	11	$	11

Total pension plan assets	$	303	$	227	$	530	$	257	$	248	$	505

⁽¹⁾	The equity funds asset class includes funds that invest in U.S. equities as well as equity securities issued by companies incorporated, listed or domiciled in countries in developed and/or emerging markets. These companies may be in the small-, mid- or large-cap categories.

⁽²⁾

The fixed income funds asset class includes investments in high quality funds. High quality fixed income funds primarily invest in low risk U.S. and non-U.S. government securities, investment-grade corporate bonds, mortgages and asset-backed securities. A significant portion of the fixed income funds asset includes investment in long-term bond funds.

⁽³⁾

The real estate funds asset class includes funds that primarily invest in entities which are principally engaged in the ownership, acquisition, development, financing, sale and/or management of income-producing real estate properties, both commercial and residential. These funds typically seek long-term growth of capital and current income that is above average relative to public equity funds.

⁽⁴⁾

The investment objective of the portfolio of this common and collective investment trust is to achieve long-term, total return in excess of the MSCI World Index Benchmark by investing in equity securities of companies worldwide, emphasizing those with above-average potential for capital appreciation.

⁽⁵⁾	Insurance contracts held by the Company’s non-U.S. plans are issued by well-known, highly rated insurance companies.

Stock-Based Compensation

12 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

Note N. Stock-Based Compensation

The Company has established equity compensation plans that provide stock-based compensation to eligible employees. The 2009 Long-Term Incentive Plan (the “2009 Plan”), which was approved by Cabot’s stockholders on March 12, 2009 and amended on March 8, 2012, authorizes the issuance of approximately 8.9 million shares of common stock. This is the Company’s only equity incentive plan under which awards may currently be made to employees, although some awards made under the Company’s 2006 Long-Term Incentive Plan (the “2006 Plan”) remain outstanding at September 30, 2013.

The terms of awards made under Cabot’s equity compensation plans are generally determined by the Compensation Committee of Cabot’s Board of Directors. The 2009 Plan allows for grants of stock options, restricted stock, restricted stock units and other stock-based awards to employees. The awards made in fiscal 2013, 2012 and 2011 under the 2009 Plan consist of grants of stock options, time-based restricted stock units, performance-based restricted stock units, and restricted stock units that will be settled in cash. The options were issued with an exercise price equal to 100% of the market price of Cabot’s common stock on the date of grant, vest over a three year period (30% on each of the first and second anniversaries of the date of grant and 40% on the third anniversary of the date of grant) and expire ten years after grant. The restricted stock units vest three years from the date of the grant. The number of shares issuable, if any, when a performance-based restricted stock unit award vests will depend on the degree of achievement of the corporate performance metrics for each year within the three-year performance period of the award. Accordingly, future compensation costs associated with outstanding awards of performance-based restricted stock units may increase or decrease based on the probability of the Company achieving the performance metrics.

As of September 30, 2013, there were 42,304 outstanding time-based and performance-based restricted stock units which will be settled by the payment of cash. Compensation expense related to these awards is remeasured throughout the vesting period and until ultimate settlement of the award. Cumulative compensation and the associated liability is recorded equal to the fair value of Cabot common stock multiplied by the applicable vesting percentage. The Company recorded liabilities associated with these cash settled awards of $1 million at both September 30, 2013 and 2012.

Prior to 2009, the principal awards made under the Company’s equity plans consisted of grants of restricted stock and stock options. The shares of restricted stock were generally purchased by the employee at a price equal to 30% of the market price of Cabot’s common stock on the date of grant, with vesting dates three years after the date of grant. The stock options issued prior to 2009 were issued with an exercise price equal to 100% of the market price of Cabot’s common stock on the date of grant, vest three years after the date of grant and expire five years after grant.

Stock-based employee compensation expense was $8 million, $10 million and $10 million, after tax, for fiscal 2013, 2012 and 2011, respectively. The Company recognized the full impact of its stock-based employee compensation expense in the Consolidated Statements of Operations for fiscal 2013, 2012 and 2011 and did not capitalize any such costs on the Consolidated Balance Sheets because those that qualified for capitalization were not material. The following table presents stock-based compensation expenses included in the Company’s Consolidated Statements of Operations:



	2013			2012			2011
	(Dollars in millions)
Cost of sales	$	4		$	5		$	5
Selling and administrative expenses		7			9			9
Research and technical expenses		1			1			1

Stock-based compensation expense		12			15			15
Income tax benefit		(4	)		(5	)		(5	)

Net stock-based compensation expense	$	8		$	10		$	10

As of September 30, 2013, Cabot has $10 million, $3 million and less than $1 million of total unrecognized compensation cost related to unvested restricted stock units, unvested options and unvested restricted stock, respectively, granted under the Company’s equity incentive plans. That cost is expected to be recognized over a weighted-average period of 1.2 years, 0.9 years and 0.4 years for unvested restricted stock units, unvested options and the unvested restricted stock, respectively.

Equity Incentive Plan Activity

The following table summarizes the total stock option, restricted stock, and restricted stock unit activity in the equity incentive plans for fiscal 2013:



	Stock Options							Restricted Stock					Restricted Stock Units
	Total Options			Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Restricted Stock			Weighted Average Grant Date Fair Value		Restricted Stock Units⁽¹⁾			Weighted Average Grant Date Fair Value
	(Shares in thousands)
Outstanding at September 30, 2012		1,579		$	24.17		$7.37		2		$	9.56		1,231		$	30.28
Granted		301			35.25		12.46		—			—		417			35.28
Performance-based adjustment⁽²⁾		—			—		—		—			—		(142	)		34.43
Exercised / Vested⁽³⁾		(245	)		19.10		4.77		(1	)		9.56		(440	)		23.84
Cancelled / Forfeited		(12	)		32.04		7.30		—			—		(27	)		32.43

Outstanding at September 30, 2013		1,623			26.93		8.71		1			9.56		1,039			34.39

Exercisable at September 30, 2013		1,029			22.63

Exercisable and expected to vest⁽⁴⁾		1,611			26.87

⁽¹⁾	The number “Granted” represents the number of shares issuable upon vesting of time-based restricted stock units and performance-based restricted stock units, assuming the Company performs at the target performance level in each year of the three-year performance period.

⁽²⁾	Represents the incremental number of shares cancelled upon vesting of outstanding performance-based restricted stock units, based on the Company achieving performance at a level less than target under the 2013 performance targets.

⁽³⁾

“Exercised / Vested” includes 160,740 Restricted Stock Units and 379 shares of restricted stock that vested during the year ended September 30, 2013 but were withheld at the request of the award recipient to cover withholding taxes associated with the vesting. The units were added back to the shares available for future issuance under our 2009 Long-Term Incentive Plan.

⁽⁴⁾	Stock options exercisable and expected to vest in the future, net of estimated forfeitures.

Stock Options

The following table summarizes information related to the outstanding and vested options on September 30, 2013:


	Total Options Outstanding		Exercisable Options		Exercisable and Expected to Vest
Aggregate Intrinsic Value (in millions)	$	26	$	21	$	26
Weighted Average Remaining Contractual Term (in years)		7.0		6.2		7.0

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value, based on the Company’s closing common stock price of $42.71 on September 30, 2013, which would have been received by the option holders had all option holders exercised their options and immediately sold their shares on that date.

The intrinsic value of options exercised during fiscal 2013, 2012 and 2011 was $5 million, $9 million and $3 million respectively, and the Company received cash of $5 million, $9 million and $4 million, respectively, from these exercises.

The Company uses the Black-Scholes option-pricing model to estimate the fair value of the options at the grant date. The estimated weighted average grant date fair values of options granted during fiscal 2013, 2012 and 2011 was $12.46, $11.64, and $12.09 per option, respectively. The fair values on the grant date were calculated using the following weighted-average assumptions:


	Years Ended September 30
	2013			2012			2011
Expected stock price volatility		46	%		45	%		43	%
Risk free interest rate		0.9	%		1.3	%		1.8	%
Expected life of options (years)		6			6			6
Expected annual dividends per year	$	0.80		$	0.72		$	0.72

The expected stock price volatility assumption was determined using the historical volatility of the Company’s common stock over the expected life of the option. The expected term reflects the anticipated time period between the measurement date and the exercise date or post-vesting cancellation date.

Restricted Stock Units

The value of restricted stock unit awards is the closing stock price at the date of the grant. The estimated weighted average grant date fair values of restricted stock unit awards granted during fiscal 2013, 2012 and 2011 was $35.28, $33.15 and $34.76, respectively. The intrinsic value of restricted stock units (meaning the fair value of the units on the date of vest) that vested during fiscal 2013, 2012 and 2011 were $16 million, $1 million and less than $1 million, respectively.

Restricted Stock

The fair value of restricted stock awards is derived by calculating the difference between the share price and the purchase price at the date of the grant. There were no restricted stock awards granted during fiscal 2013, 2012 or 2011. The intrinsic value of restricted stock that vested during fiscal 2013, 2012 and 2011 was less than $1 million, less than $1 million and $27 million, respectively.

Supplemental Retirement Savings Plan

Cabot’s Supplemental Retirement Savings Plan (“SRSP”) provides benefits to highly compensated employees in circumstances in which the maximum limits established under ERISA and the Internal Revenue Code prevent them from receiving all of the Company matching and ESOP contributions that would otherwise be provided under the qualified Retirement Savings Plan. The SRSP is non-qualified and unfunded. Contributions under the SRSP are treated as if invested in Cabot common stock. The majority of the distributions made under the SRSP are required to be paid with shares of Cabot common stock. The remaining distributions, which relate to certain grandfathered accounts, will be paid in cash based on the market price of Cabot common stock at the time of distribution. The aggregate value of the accounts that will be paid out in stock, which is equivalent to approximately 133,000 and 110,000 shares of Cabot common stock as of September 30, 2013 and 2012, respectively, is reflected at historic cost in stockholders’ equity, and the aggregate value of the accounts that will be paid in cash, which is $1 million as of both September 30, 2013 and 2012, is reflected in other long-term liabilities and marked-to-market quarterly.

Restructuring

12 Months Ended

Sep. 30, 2013

Restructuring And Related Activities [Abstract]

Restructuring

Note O. Restructuring

Cabot’s restructuring activities were recorded in the Consolidated Statements of Operations as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Cost of sales	$	28	$	13	$	16
Selling and administrative expenses		7		2		2
Research and technical expenses		2		—		—

Total	$	37	$	15	$	18

Restructuring expenses are not reflected in the results of any reportable segments, as management does not consider these activities to be representative of ongoing operating segment results.

Details of these restructuring activities and the related reserves for fiscal 2013 and 2012 were as follows:


	Severance and Employee Benefits			Environmental Remediation			Asset Impairment and Accelerated Depreciation			Asset Sales			Other			Total
	(Dollars in millions)
Reserve at September 30, 2011	$	9		$	—		$	—		$	—		$	2		$	11
Charges		3			3			7			(1	)		3			15
Costs charged against assets		—			—			(7	)		(3	)		—			(10	)
Proceeds from sale		—			—			—			4			—			4
Cash paid		(10	)		(2	)		—			—			(2	)		(14	)
Foreign currency translation adjustment		—			—			—			—			(1	)		(1	)

Reserve at September 30, 2012	$	2		$	1		$	—		$	—		$	2		$	5
Charges		13			1			19			—			4			37
Costs charged against assets		—			—			(19	)		—			(2	)		(21	)
Cash paid		(8	)		—			—			—			(3	)		(11	)

Reserve at September 30, 2013	$	7		$	2		$	—		$	—		$	1		$	10

Closure of Port Dickson, Malaysia Manufacturing Facility

On April 26, 2013, the Company announced that the Board of its joint venture carbon black company, Cabot Malaysia Sdn. Bhd. (“CMSB”), decided to cease carbon black production at its Port Dickson, Malaysia facility. The facility ceased production in June 2013. The Company holds a 51 percent equity share in CMSB. The decision, which affects approximately 90 carbon black employees, was driven by the facility’s manufacturing inefficiencies and raw materials costs.

During fiscal 2013, the consolidated joint venture has recorded pre-tax restructuring costs of approximately $18 million comprised mainly of impairment of assets at the facility and accelerated depreciation of approximately $15 million, severance charges of approximately $2 million and site demolition, clearing and environmental remediation charges of $1 million. CMSB’s net income or loss is attributable to Cabot Corporation and to the non-controlling interest in its subsidiaries. The portion of the charges that are allocable to the noncontrolling interest in CMSB (49%) are recorded within Net income attributable to noncontrolling interests in the Consolidated Statement of Operations.

The Company expects that the majority of actions related to closure of the plant will be completed in fiscal 2014 and result in total pre-tax charges to the consolidated joint venture of approximately $24 million. The expected charges are comprised of asset impairments and accelerated depreciation of $16 million, site demolition, clearing and environmental remediation of $6 million and severance charges of $2 million.

Cumulative net cash outlays related to this plan are expected to be approximately $8 million comprised primarily of $6 million for site demolition, clearing and environmental remediation, and $2 million for severance. Through fiscal 2013, CMSB has made approximately $1 million in cash payments related to this plan related mainly to severance. CMSB expects to make net cash payments of $6 million during fiscal 2014 and thereafter for site demolition, clearing and environmental remediation and $1 million related to severance. These amounts exclude any potential proceeds that may be received from the sale of land or other manufacturing assets.

As of September 30, 2013, Cabot has $1 million of accrued restructuring costs in the Consolidated Balance Sheet related to this closure which is mainly comprised of accrued severance charges.

Closure of Hong Kong, China Manufacturing Facility

In March 2012, the Company ceased manufacturing operations at its specialty compounds plant in Hong Kong and moved these operations primarily to its facility in Tianjin, China, which impacted 64 employees.

The Company has recorded pre-tax charges of $1 million and $6 million related to this plan in fiscal 2013 and 2012, respectively, comprised mainly of accelerated depreciation, severance and other closure related charges. No further material charges are expected as closure related activities are substantially complete.

Through September 30, 2013, Cabot has made cash payments of approximately $2 million, comprised primarily of severance and other charges. The Company expects to make net cash payments of less than $1 million in fiscal 2014. These amounts exclude any potential cash to be received on the sale of land rights.

As of September 30, 2013, Cabot has less than $1 million of accrued severance charges in the Consolidated Balance Sheet related to this site closure.

Other Activities

The Company has recorded pre-tax charges of approximately $15 million, $1 million and $5 million in fiscal 2013, 2012 and 2011, respectively, related to restructuring costs at other locations. Fiscal 2013 charges are comprised of $10 million severance, $3 million accelerated depreciation and asset write-offs, and $2 million of other expenses. Fiscal 2012 and 2011 are comprised mainly of severance charges. The Company anticipates recording additional charges of $7 million during fiscal 2014 and thereafter, comprised mainly of accelerated depreciation and site demolition, clearing and environmental remediation.

Through September 30, 2013, Cabot has made cash payments of $11 million related to these activities and expects to pay $8 million in fiscal 2014 and thereafter for severance, site demolition, clearing and environmental remediation and other post close operating costs at the impacted locations. As of September 30, 2013, Cabot has $5 million of accrued severance costs in the Consolidated Balance Sheet related to these activities.

Previous Actions and Sites Pending Sale

In prior years, the Company entered into different restructuring plans which have been substantially completed pending the sale of former manufacturing sites in Thane, India and Stanlow, U.K. The Company has incurred total cumulative pre-tax charges of approximately $154 million related to these plans as of September 30, 2013 comprised of $65 million for severance charges, $60 million for accelerated depreciation and asset impairments, $11 million for environmental, demolition and site clearing costs, and $19 million of other charges partially offset by $1 million gain on sale of assets. These amounts do not include any potential gain that will be recorded if the Company successfully sells its land rights and certain other manufacturing related assets in India or land in the U.K.

Restructuring expenses related to these plans were $2 million, $8 million and $13 million in fiscal 2013, 2012, and 2011, respectively. Fiscal 2013 restructuring charges from these activities mainly related to severance and impairment charges, while restructuring charges for these plans in fiscal 2012 were comprised of $3 million for environmental, demolition and site clearing costs, $2 million for accelerated depreciation and asset impairments, $1 million for severance and employee benefits, and $3 million for other post-close costs, partially offset by $1 million gain on the sale of the specialty compounds manufacturing facility in Grigno, Italy. Restructuring charges in fiscal 2011 related to these actions were comprised of $3 million for environmental, demolition and site clearing costs, $3 million for accelerated depreciation and asset impairments, $3 million for severance and employee benefits, and $4 million for other post-close costs.

Through September 30, 2013, Cabot has made net cash payments of $82 million related to these plans and expects to pay an additional $4 million in fiscal 2014 and thereafter. These amounts do not include any potential proceeds that will be received if the Company successfully sells its land rights and certain other manufacturing related assets in India or land in the U.K.

As of September 30, 2013, Cabot has $4 million of accrued environmental, severance, and other costs in the Consolidated Balance Sheet related to these activities.

Earnings Per Share

12 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Earnings Per Share

Note P. Earnings Per Share

The following tables summarize the components of the basic and diluted earnings per common share computations:


	Years Ended September 30
	2013			2012			2011
	(In millions, except per share amounts)
Basic EPS:
Net income attributable to Cabot Corporation	$	153		$	388		$	236
Less: Dividends and dividend equivalents to participating securities		—			—			1
Less: Undistributed earnings allocated to participating securities⁽¹⁾		1			3			2

Earnings allocated to common shareholders (numerator)	$	152		$	385		$	233

Weighted average common shares and participating securities outstanding		64.4			64.0			65.4
Less: Participating securities⁽¹⁾		0.6			0.6			0.8

Adjusted weighted average common shares (denominator)		63.8			63.4			64.6

Per share amounts—basic:
Income from continuing operations attributable to Cabot Corporation	$	2.34		$	2.87		$	2.80
Income from discontinued operations		0.04			3.20			0.82

Net income attributable to Cabot Corporation	$	2.38		$	6.07		$	3.62

Diluted EPS:
Earnings allocated to common shareholders	$	152		$	385		$	233
Plus: Earnings allocated to participating securities		1			3			3
Less: Adjusted earnings allocated to participating securities⁽²⁾		(1	)		(3	)		(3	)

Earnings available to common shares (numerator)	$	152		$	385		$	233

Adjusted weighted average common shares outstanding		63.8			63.4			64.6
Effect of dilutive securities:
Common shares issuable⁽³⁾		0.7			0.8			0.8

Adjusted weighted average common shares (denominator)		64.5			64.2			65.4

Per share amounts—diluted:
Income from continuing operations attributable to Cabot Corporation	$	2.32		$	2.83		$	2.77
Income from discontinued operations		0.04			3.16			0.80

Net income attributable to Cabot Corporation	$	2.36		$	5.99		$	3.57

⁽¹⁾

Participating securities consist of shares of unvested restricted stock, vested restricted stock awards held by employees in which Cabot has a security interest, and unvested time-based restricted stock units.

Undistributed earnings are the earnings which remain after dividends declared during the period are assumed to be distributed to the common and participating shareholders. Undistributed earnings are allocated to common and participating shareholders on the same basis as dividend distributions. The calculation of undistributed earnings is as follows:


	Years Ended September 30
	2013		2012		2011
	( Dollars in millions)
Calculation of undistributed earnings:
Net income attributable to Cabot Corporation	$	153	$	388	$	236
Less: Dividends declared on common stock		51		49		46
Less: Dividends and dividend equivalents to participating securities		—		—		1

Undistributed earnings	$	102	$	339	$	189

Allocation of undistributed earnings:
Undistributed earnings allocated to common shareholders	$	101	$	336	$	187
Undistributed earnings allocated to participating securities		1		3		2

Undistributed earnings	$	102	$	339	$	189

⁽²⁾

Undistributed earnings are adjusted for the assumed distribution of dividends to the dilutive securities, which are described in (3) below, and then reallocated to participating securities.

⁽³⁾

Represents incremental shares of common stock from the (i) assumed exercise of stock options issued under Cabot’s equity incentive plans; (ii) assumed issuance of shares to employees pursuant to the Company’s Supplemental Retirement Savings Plan; and (iii) assumed issuance of shares for outstanding and achieved performance-based stock unit awards issued under Cabot’s equity incentive plans using the treasury stock method. For fiscal 2013, 2012 and 2011, 301,328, 395,532 and 253,000 incremental shares of common stock were not included in the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive.

Income Taxes

12 Months Ended

Sep. 30, 2013

Income Tax Disclosure [Abstract]

Income Taxes

Note Q. Income Taxes

Income (loss) from continuing operations before income taxes and equity in net earnings of affiliated companies was as follows:


	Years ended September 30
	2013		2012		2011
	(Dollars in millions)
Income (loss) from continuing operations:
Domestic	$	35	$	13	$	(25	)
Foreign		170		232		228

Total	$	205	$	245	$	203

Tax provision (benefit) for income taxes consisted of the following:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
U.S. federal and state:
Current	$	(3	)	$	(1	)	$	(7	)
Deferred		(8	)		(8	)		(51	)

Total		(11	)		(9	)		(58	)

Foreign:
Current		70			62			57
Deferred		(1	)		2			7

Total		69			64			64

Total U.S. and foreign	$	58		$	55		$	6

The provision (benefit) for income taxes differed from the provision for income taxes as calculated using the U.S. statutory rate as follows:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
Computed tax expense at the federal statutory rate	$	72		$	86		$	70
Foreign income:
Impact of taxation at different rates, repatriation and other		(27	)		(29	)		(29	)
Impact of credit for extraordinary repatriation		—			—			(24	)
Impact of investment incentive credits		(1	)		—			(2	)
Impact of foreign losses for which a current tax benefit is not available		9			5			6
Impact of non-deductible net currency losses		18			—			—
U.S. and state benefits from research and experimentation activities		(4	)		(2	)		(3	)
Tax audit settlements		(6	)		(2	)		(12	)
Reversal of state tax valuation allowance		—			(8	)		—
Permanent and other differences		(4	)		5			—
State taxes, net of federal effect		1			—			—

Total	$	58		$	55		$	6

Significant components of deferred income taxes were as follows:


	September 30
	2013			2012
	(Dollars in millions)
Deferred tax assets:
Deferred expenses	$	29		$	13
Other		28			36
Pension and other benefits		71			84
Net operating loss carry-forwards		187			194
Foreign tax credit carry-forwards		49			12
R&D credit carry-forwards		28			27
Other business credit carry-forwards		32			31

Subtotal		424			397
Valuation allowances		(166	)		(169	)

Total deferred tax assets	$	258		$	228


	September 30
	2013			2012
	(Dollars in millions)
Deferred tax liabilities:
Intangible assets	$	(28	)	$	(10	)
Inventory		—			(2	)
Property, plant and equipment		(149	)		(141	)
Unremitted earnings of non-U.S. subsidiaries		—			(11	)

Total deferred tax liabilities	$	(177	)	$	(164	)

Beginning in fiscal year 2013, Cabot presented gross deferred tax assets and liabilities on a jurisdictional basis for major balance sheet captions. Previously, Cabot presented such amounts separately by jurisdiction on an asset grouping basis. The fiscal 2012 presentation has been changed to conform to Cabot’s current presentation.

In the fiscal 2013 tax provision, Cabot recorded $3 million of net tax charges including a $13 million foreign currency charge, offset by $10 million of net tax benefit related to tax settlements, renewal of the U.S. research and experimentation credit, and other miscellaneous tax items.

In the fiscal 2012 tax provision, Cabot recorded $11 million of net tax benefits including an $8 million state tax benefit from the release of a valuation allowance and $3 million related to settlements and other miscellaneous tax items.

In the fiscal 2011 tax provision, Cabot recorded $38 million net tax benefits including $24 million from the repatriation of high taxed income and $14 million related to tax settlements, the renewal of the U.S. research and experimentation credit, and investment incentive tax credits.

Approximately $807 million of net operating loss carryforwards (“NOLs”) and $108 million of other tax credit carryforwards remain at September 30, 2013. The benefits of these carryforwards are dependent upon taxable income during the carryforward period in the jurisdictions where they arose. Accordingly, a valuation allowance has been provided where management has determined that it is more likely than not that the carryforwards will not be utilized. The following table provides detail surrounding the expiration dates of these carryforwards:


	NOLs		Credits
	(Dollars in millions)
Expiration periods
2014 to 2020	$	391	$	18
2021 and thereafter		83		70
Indefinite carry-forwards		333		20

Total	$	807	$	108

As of September 30, 2013, provisions have not been made for U.S. income taxes or non-U.S. withholding taxes on approximately $1.18 billion of undistributed earnings of non-U.S. subsidiaries, as these earnings are considered indefinitely reinvested. Cabot continually reviews the financial position and forecasted cash flows of its U.S. consolidated group and foreign subsidiaries in order to reaffirm the Company’s intent and ability to continue to indefinitely reinvest earnings of its foreign subsidiaries or whether such earnings will need to be repatriated in the foreseeable future. Such review encompasses not only operational needs but also future capital investments. From time to time, however, the Company’s intentions relative to specific indefinitely invested amounts change because of certain unique circumstances. For example, in 2011, the Company remitted certain high taxed earnings that had previously been considered indefinitely reinvested in order to preserve a tax benefit in advance of a tax law change. These earnings could become subject to U.S. income taxes and non-U.S. withholding taxes if they were remitted as dividends, were loaned to Cabot Corporation or a U.S. subsidiary, or if Cabot should sell its stock in the subsidiaries.

As of September 30, 2013, Cabot has net deferred tax assets of $81 million, $63 million of which are in the U.S. Management believes that the Company’s history of generating domestic profits provides adequate evidence that it is more likely than not that all of the U.S. net deferred tax assets will be realized in the normal course of business. U.S. income from continuing operations adjusted for U.S. permanent differences was a profit of $70 million for the year ended September 30, 2013 and was a cumulative profit of $243 million for the three years ended September 30, 2013 including dividends from non-U.S. subsidiaries.

Realization of deferred tax assets is dependent on achieving future taxable income over an extended period of time. As of September 30, 2013, the Company would need to generate approximately $180 million in cumulative future U.S. taxable income at various times over approximately 20 years to realize all of its net U.S. deferred tax assets. The Company reviews its forecast in relation to actual results and expected trends on a quarterly basis. Failure to achieve operating income targets may change the Company’s assessment regarding the recoverability of Cabot’s deferred tax assets and such change could result in a valuation allowance being recorded against some or all of the Company’s deferred tax assets. Any increase in a valuation allowance would result in additional income tax expense, lower stockholders’ equity and could have a significant impact on Cabot’s earnings in future periods.

The valuation allowances at September 30, 2013 and 2012 represent management’s best estimate of the non-realizable portion of the deferred tax assets. The valuation allowance decreased by $3 million in 2013 due to the expiration and utilization of net operating carryforwards in certain tax jurisdictions. The valuation allowance increased by $31 million and $12 million in fiscal years 2012 and 2011, respectively, due to the uncertainty of the ultimate realization of certain future tax benefits and net operating losses generated or acquired that are included in deferred tax assets.

Cabot has filed its tax returns in accordance with the tax laws in each jurisdiction and recognizes tax benefits for uncertain tax positions when the position would more likely than not be sustained based on its technical merits and recognizes measurement adjustments when needed. As of September 30, 2013, the total amount of unrecognized tax benefits was $50 million, of which $34 million was recorded in the Company’s Consolidated Balance Sheet and $16 million of deferred tax assets, principally related to state net operating loss carry-forwards, have not been recorded. In addition, accruals of $2 million and $14 million have been recorded for penalties and interest, respectively, as of September 30, 2013 and $3 million and $15 million, respectively, as of September 30, 2012. Total penalties and interest recorded in the tax provision in the Consolidated Statement of Operations was $3 million in each of fiscal years 2013, 2012, and 2011. If the unrecognized tax benefits were recognized at a given point in time, there would be approximately $39 million favorable impact on the Company’s tax provision before consideration of the impact of the potential need for valuation allowances.

A reconciliation of the beginning and ending amount of unrecognized tax benefits for fiscal 2013, 2012 and 2011 is as follows:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
Balance at beginning of the year	$	55		$	65		$	75
Additions based on tax provisions related to the current year		1			4			2
Additions for tax positions of prior years		2			—			1
Reductions for tax provisions of prior years		(5	)		(10	)		(2	)
Reductions related to settlements		—			—			(4	)
Reductions from lapse of statute of limitations		(3	)		(4	)		(7	)

Balance at end of the year	$	50		$	55		$	65

Certain Cabot subsidiaries are under audit in jurisdictions outside of the U.S. In addition, certain statutes of limitations are scheduled to expire in the near future. It is reasonably possible that a further change in the unrecognized tax benefits may occur within the next twelve months related to the settlement of one or more of these audits or the lapse of applicable statutes of limitations; however, an estimated range of the impact on the unrecognized tax benefits cannot be quantified at this time.

Cabot files U.S. federal and state and non-U.S. income tax returns in jurisdictions with varying statutes of limitations. The 2007 through 2012 tax years generally remain subject to examination by the IRS and various tax years from 2004 through 2012 remain subject to examination by the respective state tax authorities. In significant non-U.S. jurisdictions, various tax years from 2001 through 2012 remain subject to examination by their respective tax authorities. As of September 30, 2013 Cabot’s significant non-U.S. jurisdictions include Canada, China, France, Germany, Italy, Japan, and the Netherlands.

Commitments and Contingencies

12 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note R. Commitments and Contingencies

Operating Lease Commitments

Cabot leases certain transportation vehicles, warehouse facilities, office space, machinery and equipment under cancelable and non-cancelable operating leases, most of which expire within ten years and may be renewed by Cabot. Escalation clauses, lease payments dependent on existing rates/indexes and other lease concessions are included in the minimum lease payments and such lease payments are recognized on a straight-line basis over the minimum lease term. Rent expense under such arrangements for fiscal 2013, 2012 and 2011 totaled $23 million, $15 million and $19 million, respectively. Future minimum rental commitments under non-cancelable leases are as follows:


	(Dollars in millions)
2014	$	22
2015		18
2016		14
2017		9
2018		8
2019 and thereafter		29

Total future minimum rental commitments	$	100

Other Long-Term Commitments

Cabot has entered into long-term purchase agreements primarily for the purchase of raw materials. Under certain of these agreements, the quantity of material being purchased is fixed, but the price paid changes as market prices change. Raw materials purchased under these agreements by segment for fiscal 2013, 2012 and 2011 are as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Reinforcement Materials	$	371	$	312	$	340
Performance Materials		34		47		18
Purification Solutions⁽¹⁾		34		4		N/A
Advanced Technologies		—		6		—
Other		2		1		—

Total	$	441	$	370	$	358

⁽¹⁾

The year ended September 30, 2012 includes two months of purchases for Norit.

Included in the table above are raw materials purchases from noncontrolling shareholders of consolidated subsidiaries. These purchases were $150 million, $116 million and $134 million during fiscal 2013, 2012 and 2011, respectively, and accounts payable and accrued liabilities owed to noncontrolling shareholders as of September 30, 2013 and 2012, were $11 million and $13 million, respectively.

The purchase commitments for Reinforcement Materials, Performance Materials, Purification Solutions and Advanced Technologies covered by these agreements are with various suppliers and purchases are expected to take place as follows:


	Payments Due by Fiscal Year
	2014		2015		2016		2017		2018		Thereafter		Total
	(Dollars in millions)
Reinforcement Materials	$	326	$	293	$	226	$	183	$	178	$	2,793	$	3,999
Performance Materials		42		37		33		25		25		226		388
Purification Solutions		28		15		10		10		9		17		89
Advanced Technologies		2		2		1		1		1		1		8

Total	$	398	$	347	$	270	$	219	$	213	$	3,037	$	4,484

The dollar value of these commitments has been estimated using current market prices. As noted above, these will fluctuate based on time of purchase.

Guarantee Agreements

Cabot has provided certain indemnities pursuant to which it may be required to make payments to an indemnified party in connection with certain transactions and agreements. In connection with certain acquisitions and divestitures, Cabot has provided routine indemnities with respect to such matters as environmental, tax, insurance, product and employee liabilities. In connection with various other agreements, including service and supply agreements with customers, Cabot has provided indemnities for certain contingencies and routine warranties. Cabot is unable to estimate the maximum potential liability for these types of indemnities as a maximum obligation is not explicitly stated in most cases and the amounts, if any, are dependent upon the outcome of future contingent events, the nature and likelihood of which cannot be reasonably estimated. The duration of the indemnities vary, and in many cases are indefinite. Cabot has not recorded any liability for these indemnities in the consolidated financial statements, except as otherwise disclosed.

Self-Insurance and Retention for Certain Contingencies

The Company is partially self-insured for certain third-party liabilities globally, as well as workers’ compensation and employee medical benefits in the United States. The third-party and workers’ compensation liabilities are managed through a wholly-owned insurance captive and the related liabilities are included in the consolidated financial statements. The employee medical obligations are managed by a third-party provider and the related liabilities are included in the consolidated financial statements. To limit Cabot’s potential liabilities for these risks, however, the Company purchases insurance from third-parties that provides individual and aggregate stop-loss protection. The aggregate self-insured liability in fiscal 2013 for combined U.S. third-party liabilities and U.S. workers’ compensation was $6 million, and the retention for medical costs in the United States is at most $225,000 per person per annum.

Contingencies

Cabot is a defendant, or potentially responsible party, in various lawsuits and environmental proceedings wherein substantial amounts are claimed or at issue.

Environmental Matters

As of September 30, 2013 and 2012, Cabot had $5 million and $7 million, respectively, on a discounted and undiscounted basis, reserved for environmental matters primarily related to divested businesses. In fiscal 2013 and 2012, there was $2 million and $3 million in accrued liabilities and $3 million and $4 million in other liabilities, respectively, in the Consolidated Balance Sheets for environmental matters. These amounts represent Cabot’s best estimates of the probable costs likely to be incurred by Cabot at those sites where costs are reasonably estimable based on its analysis of the extent of clean up required, alternative clean up methods available, abilities of other responsible parties to contribute and its interpretation of laws and regulations applicable to each site. Cabot reviews the adequacy of this reserve as circumstances change at individual sites. Almost all of our reserves relate to environmental issues that are mature and have been investigated and studied, and, in many cases, are subject to agreed upon remediation plans. However, depending on the results of future testing, changes in risk assessment practices, remediation techniques and regulatory requirements, newly discovered conditions, and other factors, it is reasonably possible that we could incur additional costs in excess of environmental reserves currently recorded. Management estimates, based on the latest available information, that any such future environmental remediation costs in excess of amounts already recorded would be immaterial to the Company’s consolidated financial statements.

Charges for environmental expense were less than $1 million, $3 million, and $1 million in fiscal 2013, 2012 and 2011, respectively. Cash payments were $2 million in each of fiscal 2013, 2012 and 2011 related to these environmental matters.

The operation and maintenance component of the $5 million reserve for environmental matters was $3 million at September 30, 2013. Cabot expects to make payments of $2 million in fiscal 2014, less than $1 million in each of fiscal 2015 through fiscal 2018, and a total of less than $1 million thereafter.

When deemed appropriate, the Company discounts its liability for environmental matters. A weighted average risk free rate of 3% was used for the environmental liability at September 30, 2013. The book value of the liabilities will be accreted up to the undiscounted liability value through interest expense over the expected period of cash flows. The accreted interest expense was less than $1 million for each of fiscal 2013, 2012 and 2011.

In November 2013, Cabot entered into a Consent Decree with the United States Environmental Protection Agency (“EPA”) and the Louisiana Department of Environmental Quality (“LDEQ”) regarding Cabot’s three carbon black manufacturing facilities in the United States. The Consent Decree will become effective once a public comment period has expired and it has been approved by the U.S. District Court for the Western District of Louisiana. This settlement is related to EPA’s national enforcement initiative focused on the U.S. carbon black manufacturing sector alleging non-compliance with certain regulatory and permitting requirements under The Clean Air Act, including the New Source Review (“NSR”) construction permitting requirements. Pursuant to this settlement, Cabot will pay a combined $975,000 civil penalty to EPA and LDEQ, and fund $450,000 in environmental mitigation projects in the three communities where the plants are located and install technology controls for sulfur dioxide and nitrogen oxide. The Company expects that the capital costs to install these controls will total approximately $85 million and will be incurred over approximately six and one-half years. In addition, Cabot has agreed to certain best management practices (“BMPs”) to control emissions of particulate matter at the three locations.

Other Matters

Respirator Liabilities

Cabot has exposure in connection with a safety respiratory products business that a subsidiary acquired from American Optical Corporation (“AO”) in an April 1990 asset purchase transaction. The subsidiary manufactured respirators under the AO brand and disposed of that business in July 1995. In connection with its acquisition of the business, the subsidiary agreed, in certain circumstances, to assume a portion of AO’s liabilities, including costs of legal fees together with amounts paid in settlements and judgments, allocable to AO respiratory products used prior to the 1990 purchase by the Cabot subsidiary. In exchange for the subsidiary’s assumption of certain of AO’s respirator liabilities, AO agreed to provide to the subsidiary the benefits of: (i) AO’s insurance coverage for the period prior to the 1990 acquisition and (ii) a former owner’s indemnity of AO holding it harmless from any liability allocable to AO respiratory products used prior to May 1982.

Generally, these respirator liabilities involve claims for personal injury, including asbestosis, silicosis and coal worker’s pneumoconiosis, allegedly resulting from the use of respirators that are claimed to have been negligently designed or labeled. Neither Cabot, nor its past or present subsidiaries, at any time manufactured asbestos or asbestos-containing products. At no time did this respiratory product line represent a significant portion of the respirator market.

The subsidiary transferred the business to Aearo Corporation (“Aearo”) in July 1995. Cabot agreed to have the subsidiary retain certain liabilities associated with exposure to asbestos and silica while using respirators prior to the 1995 transaction so long as Aearo paid, and continues to pay, Cabot an annual fee of $400,000. Aearo can discontinue payment of the fee at any time, in which case it will assume the responsibility for and indemnify Cabot against those liabilities which Cabot’s subsidiary had agreed to retain. The Company anticipates that it will continue to receive payment of the $400,000 fee from Aearo and thereby retain these liabilities for the foreseeable future. Cabot has no liability in connection with any products manufactured by Aearo after 1995.

In addition to Cabot’s subsidiary and as described above, other parties are responsible for significant portions of the costs of respirator liabilities, leaving Cabot’s subsidiary with a portion of the liability in only some of the pending cases. These parties include Aearo, AO, AO’s insurers, and another former owner and its insurers (collectively, with the Company’s subsidiary, the “Payor Group”).

As of both September 30, 2013 and 2012, there were approximately 42,000 claimants in pending cases asserting claims against AO in connection with respiratory products. Cabot has contributed to the Payor Group’s defense and settlement costs with respect to a percentage of pending claims depending on several factors, including the period of alleged product use. In order to quantify Cabot’s estimated share of liability for pending and future respirator liability claims, Cabot has engaged, through counsel, the assistance of Hamilton, Rabinovitz & Alschuler, Inc. (“HR&A”), a leading consulting firm in the field of tort liability valuation. The methodology developed by HR&A addresses the complexities surrounding Cabot’s potential liability by making assumptions about future claimants with respect to periods of asbestos, silica and coal mine dust exposure and respirator use. Using those and other assumptions, HR&A estimates the number of future asbestos, silica and coal mine dust claims that will be filed and the related costs that would be incurred in resolving both currently pending and future claims. On this basis, HR&A then estimates the net present value of the share of these liabilities that reflect Cabot’s period of direct manufacture and Cabot’s contractual obligations. Based on the HR&A estimates, Cabot has recorded on a discounted basis an $11 million reserve ($15 million on an undiscounted basis) to accrue for its estimated share of liability for pending and future respirator claims. The Company made payments related to its respirator liability of $2 million in fiscal 2013, $2 million in fiscal 2012 and $5 million in fiscal 2011.

The Company’s current estimate of the cost of its share of existing and future respirator liability claims is based on facts and circumstances existing at this time. Developments that could affect the Company’s estimate include, but are not limited to, (i) significant changes in the number of future claims, (ii) changes in the rate of dismissals without payment of pending silica and non-malignant asbestos claims, (iii) significant changes in the average cost of resolving claims, (iv) significant changes in the legal costs of defending these claims, (v) changes in the nature of claims received, (vi) changes in the law and procedure applicable to these claims, (vii) the financial viability of members of the Payor Group, (viii) a change in the availability of AO’s insurance coverage or the indemnity provided by AO’s former owner, (ix) changes in the allocation of costs among the Payor Group, and (x) a determination that the assumptions that were used to estimate the Company’s share of liability are no longer reasonable. The Company cannot determine the impact of these potential developments on its current estimate of its share of liability for these existing and future claims. Accordingly, the actual amount of these liabilities for existing and future claims could be different than the reserved amount.

The $11 million liability for respirator claims is recognized on a discounted basis using a discount rate of 5%, which represents management’s best estimate of the risk free rate to apply to the cash flow payments of the liability that are projected through 2065. The total expected aggregate undiscounted amount of future payments is $15 million. Cabot estimates payments of approximately $2 million in each of fiscal 2014 and 2015, $1 million in each of fiscal 2016, 2017 and 2018, and a total of $8 million in fiscal 2019 through 2065. The book value of the liabilities will be accreted up to the undiscounted liability value through interest expense over the expected cash flow period, which was less than $1 million in fiscal 2013. If the timing of Cabot’s actual payments made for respirator claims differs significantly from the Company’s estimated payment schedule, and the Company determines that it can no longer reasonably predict the timing of such payments, Cabot then could be required to record the reserve amount on an undiscounted basis on its consolidated balance sheets, causing an immediate impact to earnings.

Other

The Company has various other lawsuits, claims and contingent liabilities arising in the ordinary course of its business and with respect to the Company’s divested businesses. In the opinion of the Company, although final disposition of some or all of these other suits and claims may impact the Company’s financial statements in a particular period, they are not expected in the aggregate to have a material adverse effect on the Company’s financial position.

Concentration of Credit Risk

12 Months Ended

Sep. 30, 2013

Risks And Uncertainties [Abstract]

Concentration of Credit Risk

Note S. Concentration of Credit Risk

Credit risk represents the loss that would be recognized if counterparties failed to completely perform as contracted. Financial instruments that subject Cabot to credit risk consist principally of cash and cash equivalents, investments, trade receivables, notes receivable from sale of business ($214 million) and derivatives. Cabot maintains financial instruments with major banks and financial institutions. The Company has not experienced any material credit losses related to these instruments held at these financial institutions. Furthermore, concentrations of credit risk exist for groups of customers when they have similar economic characteristics that would cause their ability to meet contractual obligations to be similarly affected by changes in economic or other conditions.

No customer individually represented 10% or more of consolidated net sales for fiscal 2013, 2012 and 2011.

Tire manufacturers comprise a significant portion of Cabot’s trade receivable balance. The accounts receivable balance for these significant customers as a group are as follows:


	September 30
	2013		2012
	(Dollars in millions)
Tire manufacturers	$	298	$	346

Cabot has not experienced significant losses in the past from these customers. Cabot monitors its exposure to customers to manage potential credit losses.

Financial Information by Segment & Geographic Area

12 Months Ended

Sep. 30, 2013

Segment Reporting [Abstract]

Financial Information by Segment & Geographic Area

Note T. Financial Information by Segment & Geographic Area

Segment Information

The Company identifies a business as an operating segment if: i) it engages in business activities from which it may earn revenues and incur expenses; ii) its operating results are regularly reviewed by the Chief Operating Decision maker (CODM) to make decisions about resources to be allocated to the segment and assess its performance; and iii) it has available discrete financial information. The Company has determined that all of its businesses are operating segments. The CODM reviews financial information at the operating segment level to allocate resources and to assess the operating results and financial performance for each operating segment. Operating segments are aggregated into a reportable segment if the operating segments are determined to have similar economic characteristics and if the operating segments are similar in the following areas: i) nature of products and services; ii) nature of production processes; iii) type or class of customer for their products and services; iv) methods used to distribute the products or provide services; and v) if applicable, the nature of the regulatory environment.

The Company has four reportable segments: Reinforcement Materials, Performance Materials, Advanced Technologies and Purification Solutions. Reinforcement Materials represents our Rubber Blacks Business. Purification Solutions represents our Activated Carbon Business. Performance Materials is an aggregation of the Specialty Carbon and Compounds and Fumed Metal Oxides Businesses, which are similar in terms of economic characteristics, nature of products, processes, customer class and product distribution methods.

The Company has combined and disclosed five of its operating segments (Specialty Fluids, Inkjet, Aerogel, Elastomer Composites and Security Materials) into an other segment labeled “Advanced Technologies”.

Reportable segment operating profit (loss) before interest and taxes (“Segment EBIT”) is presented for each reportable segment in the financial information by the reportable segment table below on the line entitled Income (loss) from continuing operations before taxes. Segment EBIT excludes certain items, meaning items considered by management to be unusual and not representative of segment results. In addition, Segment EBIT includes Equity in net income of affiliated companies, net of tax, the full operating results of a contractual joint venture in Purification Solutions, royalties paid by equity affiliates, Net income attributable to noncontrolling interests, net of tax, and discounting charges for certain Notes receivable, but excludes Interest expense, foreign currency transaction gains and losses, interest income, dividend income, unearned revenue, the effects of LIFO accounting for inventory, and unallocated general and corporate costs. Segment assets exclude cash, short-term investments, cost investments, income taxes receivable, deferred taxes and headquarters’ assets, which are included in unallocated and other. Expenditures for additions to long-lived assets include total equity and other investments (including available-for-sale securities) and property, plant and equipment.

Reinforcement Materials

Rubber blacks are used in tires and industrial products. These products have traditionally been used in the tire industry as a rubber reinforcing agent and are also used as a performance additive. In industrial products such as hoses, belts, extruded profiles and molded goods, rubber blacks are used to improve the physical performance of the product.

Performance Materials

Performance Materials is comprised of two businesses that sell the following products: specialty grades of carbon black and thermoplastic concentrates and compounds (the Specialty Carbons and Compounds Business); and fumed silica, fumed alumina and dispersions thereof (the Fumed Metal Oxides Business). The net sales from each of these businesses for fiscal 2013, 2012 and 2011 are as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Specialty Carbons and Compounds	$	622	$	664	$	626
Fumed Metal Oxides		282		250		254

Total Performance Materials	$	904	$	914	$	880

Cabot’s specialty grades of carbon black are used to impart color, provide rheology control, enhance conductivity and static charge control, provide UV protection, enhance mechanical properties, and provide formulation flexibility through surface treatment. These products are used in a wide variety of applications, such as inks, coatings, cables, pipes, toners and electronics. In addition, Cabot manufactures and sources thermoplastic concentrates and compounds that are marketed to the plastics industry.

Fumed silica is an ultra-fine, high-purity particle used as a reinforcing, thickening, abrasive, thixotropic, suspending or anti-caking agent in a wide variety of products produced for the automotive, construction, microelectronics, and consumer products industries. These products include adhesives, sealants, cosmetics, inks, toners, silicone rubber, coatings, polishing slurries and pharmaceuticals. Fumed alumina, also an ultra-fine, high-purity particle, is used as an abrasive, absorbent or barrier agent in a variety of products, such as inkjet media, lighting, coatings, cosmetics and polishing slurries.

Advanced Technologies

The net sales from each of the Advanced Technologies businesses are as follows::


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Inkjet Colorants	$	64	$	66	$	65
Aerogel		21		18		24
Security Materials		7		9		11
Elastomer Composites		29		23		17
Specialty Fluids		101		94		69

Total Advanced Technologies	$	222	$	210	$	186

The Inkjet Colorants Business produces and sells aqueous inkjet colorants primarily to the inkjet printing market. The Company’s inkjet colorants are high-quality pigment-based black and color dispersions based on Cabot’s patented surface modification technology. The dispersions are used in aqueous inkjet inks to impart color (optical density or chroma), sharp print characteristics and durability (waterfastness, lightfastness and rub resistance) while maintaining high printhead reliability. Cabot’s inkjet colorants serve various inkjet printing applications, including small office and home office, corporate office, and commercial printing, as well as other niche applications that require a high level of dispersibility and colloidal stability. The Company also sells inks with its pigment based colorant dispersions into the emerging commercial printing segment for digital print.

Aerogel is a hydrophobic, silica-based particle with a high surface area that is used in a variety of thermal insulation and specialty chemical applications. In the building and construction industry, the product is used in insulative sprayable plasters and composite building products, as well as translucent skylight, window, wall and roof systems for insulating eco-daylighting applications. In the oil and gas industry, aerogel is used to insulate subsea pipelines. In the specialty chemicals industry, the product is used to provide matte finishing, insulating and thickening properties for use in a variety of applications. These applications include incorporation of aerogel into highly thermal insulative coatings formulations for safe touch and improved energy efficiency. The Company continues to focus on application and market development activities for use of aerogel in these and other new applications.

The principal area of commercial focus for the Security Materials Business is in developing covert taggants for a broad range of anti-counterfeiting security applications, including brand security, currency, tax stamps, identification and fuel markers. Covert taggants are invisible, unique markers that are added to products to determine their authenticity through the use of custom detectors or readers. The Company’s taggants are manufactured using a proprietary process, which produces highly uniform materials with unique signatures.

The Elastomer Composites Business has developed elastomer composite products that are compounds of natural latex rubber and carbon black made by a patented liquid phase process. These compounds improve abrasion/wear resistance, reduce fatigue and reduce rolling resistance compared to natural rubber/carbon black compounds made by conventional methods. These products are targeted primarily for tire applications.

The Specialty Fluids Business principally produces and markets cesium formate as a drilling and completion fluid for use primarily in high pressure and high temperature oil and gas well construction. Cesium formate products are solids-free, high-density fluids that have a low viscosity, enabling safe and efficient well construction and workover operations. The fluid is resistant to high temperatures, minimizes damage to producing reservoirs and is readily biodegradable in accordance with testing guidelines set by the Organization for Economic Cooperation and Development. In a majority of applications, cesium formate is blended with other formates or products. Income from continuing operations before taxes for the Specialty Fluids Business was $46 million, $44 million, and $22 million in fiscal 2013, 2012, and 2011, respectively. Total assets were $110 million, $111 million, and $101 million in fiscal years 2013, 2012 and 2011, respectively. Capital expenditures were $5 million, $5 million, and $3 million in fiscal years 2013, 2012 and 2011, respectively. Depreciation and amortization was $2 million for fiscal years 2013, 2012, and 2011. There was no equity in earnings of affiliated companies related to the Specialty Fluids Business for fiscal years 2013, 2012, and 2011.

Purification Solutions

The Company’s activated carbon products are typically used for the purification of water, air, food and beverages, pharmaceuticals and other liquids and gases, as either a colorant or a decoloring agent in the production of products for food and beverage applications and as a chemical carrier in slow release applications. In gas and air applications, one of the uses of activated carbon is for the removal of mercury in flue gas streams. In certain applications, used activated carbon can be reactivated for further use by removing the contaminants from the pores. In addition to activated carbon production and reactivation, the Company also provides activated carbon solutions through on-site equipment and services, including delivery systems for activated carbon injection in coal-fired utilities, mobile water filter units and carbon reactivation services. Fiscal 2013 Purification Solutions Segment EBIT includes an allocation of corporate administrative and functional support costs. In the prior year, these allocations were reflected in unallocated corporate costs and other segment results.

Financial information by reportable segment is as follows:


	Reinforcement Materials		Performance Materials		Advanced Technologies		Purification Solutions			Segment Total		Unallocated and Other^{(1), (3)}			Consolidated Total
	(Dollars in millions)
Years Ended September 30
2013
Revenues from external customers⁽²⁾	$	1,902	$	904	$	222	$	348		$	3,376	$	87		$	3,463
Depreciation and amortization		81		49		10		54			194		(4	)		190
Equity in earnings of affiliated companies		9		2		—		4			15		(4	)		11
Income (loss) from continuing operations before taxes⁽³⁾		188		132		68		(4	)		384		(179	)		205
Assets⁽⁴⁾		1,512		688		198		1,388			3,786		447			4,233
Total expenditures for additions to long-lived assets⁽⁵⁾		172		46		5		38			261		3			264
2012
Revenues from external customers⁽²⁾	$	2,019	$	914	$	210	$	61		$	3,204	$	96		$	3,300
Depreciation and amortization		82		47		13		8			150		6			156
Equity in earnings of affiliated companies		9		1		—		1			11		—			11
Income (loss) from continuing operations before taxes⁽³⁾		227		128		49		5			409		(164	)		245
Assets⁽⁴⁾		1,527		717		209		1,433			3,886		513			4,399
Total expenditures for additions to long-lived assets⁽⁵⁾		163		87		16		350			616		6			622
2011
Revenues from external customers⁽²⁾	$	1,952	$	880	$	186	$	N/A		$	3,018	$	84		$	3,102
Depreciation and amortization		80		37		14		N/A			131		8			139
Equity in earnings of affiliated companies		7		1		—		N/A			8		—			8
Income (loss) from continuing operations before taxes⁽³⁾		183		140		31		N/A			354		(151	)		203
Assets⁽⁴⁾		1,509		661		191		N/A			2,361		780			3,141
Total expenditures for additions to long-lived assets⁽⁵⁾		126		99		10		N/A			235		6			241

⁽¹⁾	Unallocated and other includes certain items and eliminations necessary to reflect management’s reporting of operating segment results. These items are reflective of the segment reporting presented to the Chief Operating Decision Maker.

⁽²⁾	Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, the impact of the corporate adjustment for unearned revenue and Notes receivable. See table below:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Royalties paid by equity affiliates, other operating revenues, the impact of the corporate adjustment for unearned revenue, unconsolidated equity affiliates and discounting charges for certain Notes Receivable	$	5	$	11	$	(2	)
Shipping and handling fees		82		85		86

Total	$	87	$	96	$	84

⁽³⁾	Income (loss) from continuing operations before taxes for Unallocated and Other includes:


	Years Ended September 30
	2013			2012			2011
	(Dollars in millions)
Interest expense	$	(62	)	$	(46	)	$	(39	)
Total certain items, pre-tax^(a)		(56	)		(51	)		(19	)
Equity in earnings of affiliated companies, net of tax^(b)		(11	)		(11	)		(8	)
Unallocated corporate costs^(c)		(49	)		(56	)		(53	)
General unallocated expense^(d)		(1	)		—			(32	)

Total	$	(179	)	$	(164	)	$	(151	)

^(a)

Certain items are items that management does not consider to be representative of operating segment results and they are, therefore, excluded from Segment EBIT. Certain items, pre-tax, for fiscal 2013 primarily include $37 million related to global restructuring activities, $21 million for acquisition related charges (consisting of $10 million for certain other one-time integration costs and $11 million of additional charges related to acquisition accounting adjustments for the acquired inventory) and $1 million for environmental reserves offset by $3 million of certain foreign currency gains recorded by foreign subsidiaries. Certain items, pre-tax, for fiscal 2012 primarily include $17 million related to global restructuring activities, $26 million for acquisition related charges (consisting of $14 million of legal and professional fees, $3 million for certain other one-time integration costs and $9 million of additional charges related to acquisition accounting adjustments for the acquired inventory), $4 million for environmental and legal reserves, and a $4 million addition in the reserve for respirator claims. Certain items, pre-tax, for fiscal 2011 primarily include charges for global restructuring activities discussed in Note O.

^(b)

Equity in earnings of affiliated companies, net of tax, is included in Segment EBIT and is removed from Unallocated and other to reconcile to income (loss) from operations before taxes.

^(c)

Unallocated corporate costs are not controlled by the segments and primarily benefit corporate interests.

^(d)

General unallocated expense consists of gains (losses) arising from foreign currency transactions, net of other foreign currency risk management activities, the impact of accounting for certain inventory on a LIFO basis, the profit or loss related to the corporate adjustment for unearned revenue, and the impact of including the full operating results of an equity affiliate in Purification Solutions segment EBIT. Additionally, for fiscal 2011, this amount included a $3 million charge related to a change in the net worth tax regulations in Colombia, and $3 million related to a portion of the benefit from a legal judgment.

⁽⁴⁾	Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters’ assets, and current and non-current assets held for sale.

⁽⁵⁾	Expenditures for additions to long-lived assets include total equity and other investments (including available-for-sale securities) and property, plant and equipment.

Geographic Information

Sales are attributed to the United States and to all foreign countries based on the location from which the sale originated. Revenues from external customers and long-lived assets attributable to an individual country, other than the United States, China and Netherlands, were not material for disclosure.

Revenues from external customers and long-lived asset information by geographic area are summarized as follows:


	United States		China		Netherlands		Other Foreign Countries		Consolidated Total
	(Dollars in millions)
Years Ended September 30,
2013
Revenues from external customers	$	825	$	558	$	224	$	1,856	$	3,463
Net property, plant and equipment	$	493	$	385	$	211	$	516	$	1,605
2012
Revenues from external customers	$	695	$	543	$	131	$	1,931	$	3,300
Net property, plant and equipment	$	486	$	305	$	208	$	553	$	1,552
2011
Revenues from external customers	$	589	$	554	$	115	$	1,844	$	3,102
Net property, plant and equipment	$	233	$	274	$	45	$	484	$	1,036

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8906-108599

Quarterly Financial Information Disclosure [Abstract]

Unaudited Quarterly Financial Information

12 Months Ended

Sep. 30, 2013

Unaudited Quarterly Financial Information

Note U. Unaudited Quarterly Financial Information

Unaudited financial results by quarter for fiscal 2013 and 2012 are summarized below:


	Quarter Ended
	December			March			June			September			Year
	(Dollars in millions, except per share amounts)
Fiscal 2013
Consolidated Net Income
Net sales and other operating revenues	$	820		$	842		$	903		$	898		$	3,463

Gross profit		147			144			177			168			636
Selling and administrative expenses		73			77			73			76			299
Research and technical expenses		19			18			18			19			74

Income from operations		55			49			86			73			263
Net interest expense and other charges		(14	)		(13	)		(13	)		(18	)		(58	)

Income from continuing operations before income taxes and equity in earnings of affiliated companies		41			36			73			55			205
Provision for income taxes		(19	)		(16	)		(16	)		(7	)		(58	)
Equity in earnings of affiliated companies, net of tax		3			3			3			2			11
Income from discontinued operations, net of tax		(1	)		—			2			1			2

Net income		24			23			62			51			160
Net income attributable to noncontrolling interests, net of tax		4			(4	)		3			4			7

Net income attributable to Cabot Corporation	$	20		$	27		$	59		$	47		$	153

Income per share—basic:
Income from continuing operations	$	0.33		$	0.43		$	0.86		$	0.72		$	2.34
Income from discontinued operations		(0.02	)		—			0.04			0.02			0.04

Net income attributable to Cabot Corporation	$	0.31		$	0.43		$	0.90		$	0.74		$	2.38

Income per share—diluted:
Income from continuing operations	$	0.33		$	0.42		$	0.86		$	0.71		$	2.32
Income from discontinued operations		(0.02	)		—			0.04			0.02			0.04

Net income attributable to Cabot Corporation	$	0.31		$	0.42		$	0.90		$	0.73		$	2.36


	Quarter Ended
	December			March			June			September			Year
	(Dollars in millions, except per share amounts)
Fiscal 2012
Consolidated Net Income
Net sales and other operating revenues	$	762		$	844		$	846		$	848		$	3,300

Gross profit		143			173			175			157			648
Selling and administrative expenses		65			66			68			86			285
Research and technical expenses		17			20			17			19			73

Income from operations		61			87			90			52			290
Net interest expense and other charges		(6	)		(11	)		(12	)		(16	)		(45	)

Income from continuing operations before taxes and equity earnings of affiliated companies		55			76			78			36			245
Provision for income taxes		(16	)		(23	)		(16	)		—			(55	)
Equity in earnings of affiliated companies		1			3			4			3			11
Income from discontinued operations, net of tax		11			189			4			1			205

Net income		51			245			70			40			406
Net income attributable to noncontrolling interests, net of tax		5			5			4			4			18

Net income attributable to Cabot Corporation	$	46		$	240		$	66		$	36		$	388

Income per share—basic:
Income from continuing operations	$	0.55		$	0.80		$	0.97		$	0.55		$	2.87
Income from discontinued operations		0.17			2.94			0.07			0.02			3.20

Net income attributable to Cabot Corporation	$	0.72		$	3.74		$	1.04		$	0.57		$	6.07

Income per share—diluted:
Income from continuing operations	$	0.55		$	0.78		$	0.96		$	0.54		$	2.83
Income from discontinued operations		0.16			2.92			0.06			0.02			3.16

Net income attributable to Cabot Corporation	$	0.71		$	3.70		$	1.02		$	0.56		$	5.99

Significant Accounting Policies (Policies)

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Principles of Consolidation

Principles of Consolidation

Cash and Cash Equivalents

Cash and Cash Equivalents

Inventories

Inventories

Investments

Investments

Property, Plant and Equipment

Property, Plant and Equipment

Intangible Assets and Goodwill

Intangible Assets and Goodwill

Assets Held for Rent

Assets Held for Rent

Assets held for rent represent Specialty Fluids cesium formate product that is available to customers in the normal course of business. Assets held for rent are stated at average cost.

Asset Retirement Obligations

Asset Retirement Obligations

Impairment of Long-Lived Assets

Impairment of Long-Lived Assets

Foreign Currency Translation

Foreign Currency Translation

Financial Instruments

Financial Instruments

Revenue Recognition

Revenue Recognition

Shipping and handling charges related to sales transactions are recorded as sales revenue when billed to customers or included in the sales price.

The following table shows the relative size of the revenue recognized in each of the Company’s reportable segments:


	Years ended September 30
	2013			2012			2011
Reinforcement Materials		56	%		63	%		65%
Performance Materials		27	%		28	%		29%
Advanced Technologies		7	%		7	%		6%
Purification Solutions		10	%		2	%⁽¹⁾		N/A

⁽¹⁾	Fiscal 2012 includes two months of revenue for Purification Solutions, which the Company acquired on July 31, 2012.

Cost of Sales

Cost of Sales

Accounts and Notes Receivable

Accounts and Notes Receivable

Notes Receivable from Sale of Business

Notes receivable from sale of business

Stock-Based Compensation

Stock-based Compensation

Selling and Administrative Expenses

Selling and Administrative Expenses

Selling and administrative expenses consist of salaries and fringe benefits of sales and office personnel, general office expenses and other expenses not directly related to manufacturing operations.

Research and Technical Expenses

Research and Technical Expenses

Research and technical expenses include salaries, equipment and material expenditures, and contractor fees and are expensed as incurred.

Income Taxes

Income Taxes

Accumulated Other Comprehensive Income

Accumulated Other Comprehensive Income

Accumulated other comprehensive items in the accompanying balance sheet consist of the following items net of tax:


	Year ended September 30			Year ended September 30
	2013			2012
	(In millions)			(In millions)
Foreign currency translation adjustment at beginning of year	$	167		$	163
Net foreign currency translation adjustments		(13	)		4

Balance at end of year	$	154		$	167

Unrealized gain on investments and derivative instruments at beginning of year		—		$	1
Net unrealized gains		2			(1	)

Balance at end of year	$	2		$	—

Pension and other postretirement benefit plans at beginning of year		(75	)	$	(58	)
Net change in pension and other postretirement benefit plans		22			(17	)

Balance at end of year	$	(53	)	$	(75	)

Total accumulated other comprehensive income	$	103		$	92

Environmental Costs

Environmental Costs

Use of Estimates

Use of Estimates

Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

Segment Reporting Revenue Percentage

The following table shows the relative size of the revenue recognized in each of the Company’s reportable segments:


	Years ended September 30
	2013			2012			2011
Reinforcement Materials		56	%		63	%		65%
Performance Materials		27	%		28	%		29%
Advanced Technologies		7	%		7	%		6%
Purification Solutions		10	%		2	%⁽¹⁾		N/A

⁽¹⁾	Fiscal 2012 includes two months of revenue for Purification Solutions, which the Company acquired on July 31, 2012.

Accumulated Other Comprehensive Items in Accompanying Balance Sheet

Accumulated other comprehensive items in the accompanying balance sheet consist of the following items net of tax:


	Year ended September 30			Year ended September 30
	2013			2012
	(In millions)			(In millions)
Foreign currency translation adjustment at beginning of year	$	167		$	163
Net foreign currency translation adjustments		(13	)		4

Balance at end of year	$	154		$	167

Unrealized gain on investments and derivative instruments at beginning of year		—		$	1
Net unrealized gains		2			(1	)

Balance at end of year	$	2		$	—

Pension and other postretirement benefit plans at beginning of year		(75	)	$	(58	)
Net change in pension and other postretirement benefit plans		22			(17	)

Balance at end of year	$	(53	)	$	(75	)

Total accumulated other comprehensive income	$	103		$	92

Acquisitions (Tables)

12 Months Ended

Sep. 30, 2013

Business Combinations [Abstract]

Components and Allocation of Purchase Price

The following table presents the components and allocation of the purchase price, including the measurement period adjustments:


	At Acquisition Date (As reported at September 30, 2012)			Measurement Period Adjustments			At Acquisition Date (As adjusted at September 30, 2013)
	(Dollars in millions)
Current assets	$	207		$	(4	)	$	203
Property, plant and equipment		385			(14	)		371
Other non-current assets		72			4			76
Intangible assets		325			(8	)		317
Goodwill		432			22			454
Current liabilities		(98	)		—			(98	)
Deferred non-current tax liabilities		(176	)		4			(172	)
Other non-current liabilities		(34	)		(4	)		(38	)

Total purchase price	$	1,113		$	—		$	1,113

Pro Forma Net Sales and Results of Operations

The following table provides pro forma net sales and earnings for fiscal 2012.


	Year ended September 30
	2012 (unaudited)
	(in millions)
Net sales	$	3,585
Income from continuing operations		209

Discontinued Operations (Tables)

12 Months Ended

Sep. 30, 2013

Discontinued Operations And Disposal Groups [Abstract]

Components of Discontinued Operations

The following table summarizes the results from discontinued operations:


	Years Ended September 30
	2013			2012			2011
	(Dollars in millions)
Net sales and other operating revenues	$	—		$	46		$	201

Income from operations before income taxes		—			21			84
Provision for income taxes on operations		—			(7	)		(31	)

Income from operations, net of tax	$	—		$	14		$	53

(Loss) Gain on sale of discontinued operations		(2	)		300			—
Benefit from (Provision for) income taxes on gain (loss) on sale		4			(109	)		—

Gain on sale of discontinued operations, net of tax		2			191			—

Income from discontinued operations, net of tax	$	2		$	205		$	53

Components of Company's Inventories

Tabular disclosure of disposal groups, which may include the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the classification and carrying value of the assets and liabilities comprising the disposal group, and the segment in which the disposal group was reported. Also may include the amount of adjustments to amounts previously reported in discontinued operations such as resolution of contingencies arising from the disposal transaction or the operations of the component prior to disposal.

+ References + Details

Inventories (Tables)

12 Months Ended

Sep. 30, 2013

Inventory Disclosure [Abstract]

Inventories, net of LIFO, obsolete, unmarketable and slow moving reserves, are as follows:


	September 30
	2013		2012
	(Dollars in millions)
Raw materials	$	102	$	131
Work in process		2		5
Finished goods		310		351
Other		44		46

Total	$	458	$	533

Property, Plant and Equipment (Tables)

12 Months Ended

Sep. 30, 2013

Property Plant And Equipment [Abstract]

Components of Property, Plant and Equipment

Property, plant and equipment is summarized as follows:


	September 30
	2013			2012
	(Dollars in millions)
Land and land improvements	$	138		$	167
Buildings		511			495
Machinery and equipment		2,511			2,379
Other		238			226
Construction in progress		278			244

Total property, plant and equipment		3,676			3,511
Less: accumulated depreciation		(2,071	)		(1,959	)

Net property, plant and equipment	$	1,605		$	1,552

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Sep. 30, 2013

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Goodwill Balances

The carrying amount of goodwill attributable to each reportable segment with goodwill balances and the changes in those balances during the years ended September 30, 2013 and 2012 are as follows:


	Reinforcement Materials			Performance Materials		Advanced Technologies		Purification Solutions		Total
	(Dollars in millions)
Balance at September 30, 2011	$	27		$	11	$	2	$	—	$	40
Goodwill acquired		—			—		—		432		432
Foreign currency translation adjustment		1			—		—		7		8

Balance at September 30, 2012		28			11		2		439		480
Measurement period adjustments⁽¹⁾		—			—		—		22		22
Foreign currency translation adjustment		(3	)		—		—		5		2

Balance at September 30, 2013	$	25		$	11	$	2	$	466	$	504

⁽¹⁾	Refer to Note C for further details related to the measurement period adjustments.

Schedule of Intangible Assets

The following table provides information regarding the Company’s intangible assets:


	Years Ended September 30
	2013							2012
	Gross Carrying Value		Accumulated Amortization			Net Intangible Assets		Gross Carrying Value		Accumulated Amortization			Net Intangible Assets
	(Dollars in millions)
Intangible assets with finite lives
Developed technology	$	155	$	(9	)	$	146	$	151	$	(2	)	$	149
Customer relationships⁽¹⁾		113		(7	)		106		121		(1	)		120
Other intangible assets		3		(2	)		1		6		(3	)		3

Total intangible assets, finite lives	$	271	$	(18	)	$	253	$	278	$	(6	)	$	272
Trademarks, indefinite lives		57		—			57		58		—			58

Total intangible assets	$	328	$	(18	)	$	310	$	336	$	(6	)	$	330

⁽¹⁾	The change in the gross carrying value of the Customer relationships intangible asset is primarily due to measurement period adjustments as described in Note C.

Accounts Payable, Accrued Liabilities and Other Liabilities (Tables)

12 Months Ended

Sep. 30, 2013

Payables And Accruals [Abstract]

Components of Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities included in current liabilities consist of the following:


	September 30
	2013		2012
	(Dollars in millions)
Accounts payable	$	398	$	425
Accrued employee compensation		41		46
Other accrued liabilities		95		135

Total	$	534	$	606

Components of Other Long-Term Liabilities

Other long-term liabilities consist of the following:


	September 30
	2013		2012
	(Dollars in millions)
Employee benefit plan liabilities	$	149	$	190
Non-current tax liabilities		47		53
Financial instrument liabilities		—		26
Other accrued liabilities		69		45

Total	$	265	$	314

Debt and Other Obligations (Tables)

12 Months Ended

Sep. 30, 2013

Debt Disclosure [Abstract]

Schedule of Long-Term Obligations

The Company’s long-term obligations, the fiscal year in which they mature and their respective interest rates are summarized below:


	September 30
	2013			2012
	(Dollars in millions)
Variable Rate Debt:
$750 million Revolving Credit Facility, expires 2016	$	—		$	189
Chinese Renminbi Notes, due through 2016, 5.40%—6.77%		47			11

Total variable rate debt		47			200
Fixed Rate Debt:
5% Notes due 2017	$	300		$	300
2.55% Notes due 2018		250			250
3.7% Notes due 2022		350			350
Medium Term Notes:
Notes due 2019, 7.42%		30			30
Notes due 2022, 8.346%—8.47%		15			15
Note due 2028, 6.57%—7.28%		8			8

Total Medium Term Notes	$	53		$	53
Eurobond, due 2013, 5.25%		—			177
ESOP Note, due 2014, 8.29%		2			8
Chinese Renminbi Notes, due through 2018, 4.68%—6.65%		16			5

Total fixed rate debt		971			1,143
Capital lease obligations, due through 2031		18			16
Unamortized debt discount		(2	)		(2	)

Total debt		1,034			1,357
Less current portion of long-term debt		(14	)		(185	)

Total long-term debt	$	1,020		$	1,172

Schedule of Future Years Payment

The aggregate principal amounts of long-term debt and capital lease obligations due in each of the five years from fiscal 2014 through 2018 are as follows:


Fiscal Years Ending	Principal payments on long term debt		Payments on Capital Lease Obligations			Total
	(Dollars in millions)
2014	$	12	$	5		$	17
2015		30		4			34
2016		11		3			14
2017		300		3			303
2018		262		3			265
Thereafter		403		24			427
Less: executory costs and interest		—		(24	)		(24	)

Total	$	1,018	$	18		$	1,036

Financial Instruments and Fair Value Measurements (Tables)

12 Months Ended

Sep. 30, 2013

Text Block [Abstract]

Schedule of Fair Value of Derivatives, Net of Legal Right to Offset Derivative Settlements

The derivatives presented in the table below are presented by derivative type, net of the legal right to offset derivative settlements by each counterparty:


	September 30
	2013		2012
	Level 2		Level 2
	(Dollars in Millions)
Assets at fair value:
Guaranteed investment contract⁽¹⁾	$	14	$	14
Derivatives relating to interest rates⁽²⁾		—		2

Total assets at fair value	$	14	$	16

Liabilities at fair value:
Derivatives relating to foreign currency⁽²⁾	$	—	$	28
Hedged long-term debt⁽³⁾		—		36

Total liabilities at fair value	$	—	$	64

⁽¹⁾	Included in “Other assets” in the Consolidated Balance Sheets.

⁽²⁾	Included in “Prepaid expenses and other current assets”, “Other assets”, “Accounts payable and accrued liabilities” or “Other liabilities” in the Consolidated Balance Sheets.

⁽³⁾	Included in “Current portion of long-term debt” in the fiscal 2012 Consolidated Balance Sheets.

Derivatives (Tables)

12 Months Ended

Sep. 30, 2013

Foreign Currency Risk Management

The following table provides details of the derivatives held as of September 30, 2013 and 2012 to manage foreign currency risk.


Description	Borrowing	Notional Amount		Hedge Designation
Description	Borrowing	September 30, 2013	September 30, 2012	Hedge Designation
Cross Currency Swap	Eurobond (80% of $175 million)	—	USD 140 million swapped to EUR 124 million	No designation

Cross Currency Swap	Eurobond (20% of $175 million)	—	USD 35 million swapped to EUR 31 million	No designation

Forward Foreign Currency Contracts⁽¹⁾	N/A	USD 31 million	USD 106 million	No designation

Forward Foreign Currency Contracts⁽¹⁾	N/A	—	USD 3 million	Cash Flow

⁽¹⁾	Cabot’s forward foreign exchange contracts are denominated primarily in the Australian dollar, British pound sterling, Canadian dollar, Chinese renminbi, Czech koruna, Euro, Indian rupee and Japanese yen.

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value


Fair Value of Derivative Instruments	Consolidated Balance Sheet Caption	September 30, 2013		September 30, 2012
		(Dollars in millions)
Asset Derivatives
Derivatives designated as hedges Interest rate⁽¹⁾	Accounts payable and accrued liabilities	$	—	$	2

Derivatives not designated as hedges Other⁽²⁾	Prepaid expenses and other current assets		—		1

Total Asset Derivatives		$	—	$	3

Liability Derivatives
Derivatives not designated as hedges Foreign currency⁽¹⁾	Accounts payable and accrued liabilities, and Other liabilities	$	—	$	28
Other⁽²⁾	Prepaid expenses and other current assets		—		1

Total derivatives not designated as hedges		$	—	$	29

Total Liability Derivatives		$	—	$	29

⁽¹⁾

⁽²⁾	Contracts in an asset and liability position presented on a gross basis in fiscal 2012 in this table have the legal right of offset and, therefore, are presented on a net basis in “Prepaid expenses and other current assets” in the Consolidated Balance Sheets.

Interest Rate Risk Management [Member]

Schedule of Derivatives Fair Value Interest Rate

The following table provides details of the derivatives held as of September 30, 2012 to manage interest rate risk.


		Notional Amount
Description	Borrowing	September 30, 2013	September 30, 2012	Hedge Designation
Interest Rate Swap—Fixed to Variable⁽¹⁾	Eurobond (20% of $175 million)	—	USD 35 million	Fair Value

⁽¹⁾	In September 2013, the Company settled the Eurobond and related foreign currency and interest rate swaps.

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41641-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41638-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579240-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41620-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plans (Tables)

12 Months Ended

Sep. 30, 2013

Change in Benefit Obligations and Change in Plan Assets

The following provides information about benefit obligations, plan assets, the funded status and weighted-average assumptions of the defined benefit pension and postretirement benefit plans:


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Change in Benefit Obligations:
Benefit obligation at beginning of year	$	195		$	423		$	147		$	236		$	64		$	18		$	64		$	15
Service cost		6			9			5			7			—			—			1			—
Interest cost		6			15			7			11			2			1			2			1
Plan participants’ contribution		—			2			—			1			—			—			—			—
Foreign currency exchange rate changes		—			—			—			5			—			(1	)		—			1
(Gain) loss from changes in actuarial assumptions		(19	)⁽¹⁾		12			12			38			(6	)		—			1			2
Benefits paid⁽²⁾		(11	)		(17	)		(11	)		(11	)		(5	)		(1	)		(5	)		(1	)
Settlements or curtailment gain		(7	)		(2	)		(1	)		(4	)		—			—			(1	)		—
Acquisition of Norit		—			—			36			140			—			—			2			—
Divestiture of CSM		—			(5	)		—			—			—			—			—			—
Other		—			2			—			(1	)		—			—			—			—

Benefit obligation at end of year	$	170		$	439		$	195		$	422		$	55		$	17		$	64		$	18


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Change in Plan Assets:
Fair value of plan assets at beginning of year	$	149		$	356		$	103		$	197		$	—		$	—		$	—		$	—
Actual return on plan assets		17			22			23			24			—			—			—			—
Employer contribution		—			13			8			13			5			—			5			1
Plan participants’ contribution		—			2			—			1			—			—			—			—
Foreign currency exchange rate changes		—			4			—			5			—			—			—			—
Benefits paid⁽²⁾		(10	)		(17	)		(11	)		(11	)		(5	)		—			(5	)		(1	)
Settlements		—			(1	)		—			(5	)		—			—			—			—
Acquisition of Norit		—			—			27			133			—			—			—			—
Divestiture of Supermetals Business		—			(3	)		—			—			—			—			—			—
Expenses paid from assets		(1	)		(1	)		(1	)		(1	)		—			—			—			—

Fair value of plan assets at end of year	$	155		$	375		$	149		$	356		$	—		$	—		$	—		$	—

Funded status	$	(15	)	$	(64	)	$	(46	)	$	(66	)	$	(55	)	$	(17	)	$	(64	)	$	(18	)

Recognized liability	$	(15	)	$	(64	)	$	(46	)	$	(66	)	$	(55	)	$	(17	)	$	(64	)	$	(18	)

(1)

(2)	Included in this amount is $7 million that the Company paid directly to the participants in its defined benefit plans in both fiscal 2013 and 2012.

Assumptions Used to Determine Pension Benefit Obligations

Pension Assumptions and Strategy

The following assumptions were used to determine the pension benefit obligations at September 30:


	Assumptions as of September 30
	2013						2012						2011
	Pension Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
Actuarial assumptions as of the year-end measurement date:
Discount rate		4.5	%		3.8	%		3.5	%		3.6	%		4.5	%		4.8	%
Rate of increase in compensation		3.0	%		3.1	%		3.5	%		3.1	%		3.8	%		3.1	%
Actuarial assumptions used to determine net periodic benefit cost during the year:
Discount rate		3.5	%		3.6	%		4.5	%		4.8	%		4.5	%		4.3	%
Expected long-term rate of return on plan assets		7.8	%		5.3	%		7.8	%		5.3	%		7.8	%		6.1	%
Rate of increase in compensation		3.5	%		3.1	%		3.8	%		3.2	%		3.8	%		3.3	%

Post Retirement Assumptions and Strategy

The following assumptions were used to determine the post retirement benefit obligations at September 30:


	Assumptions as of September 30
	2013						2012						2011
	Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
Actuarial assumptions as of the year-end measurement date:
Discount rate		4.0	%		4.4	%		3.3	%		3.9	%		4.5	%		4.9	%
Initial health care cost trend rate		7.5	%		7.5	%		8.0	%		7.4	%		8.5	%		8.0	%
Actuarial assumptions used to determine net cost during the year:
Discount rate		3.3	%		3.9	%		4.5	%		4.9	%		4.5	%		4.8	%
Initial health care cost trend rate		8.0	%		7.4	%		8.5	%		7.9	%		7.5	%		8.0	%

Net Amounts Recognized in Consolidated Balance Sheets

The rates utilized are selected because they represent long-term, high quality, fixed income benchmarks that approximate the long-term nature of Cabot’s pension obligations and related payouts.


	Years Ended September 30
	2013						2012						2013						2012
	Pension Benefits												Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign
	(Dollars in millions)
Net Amounts Recognized in the Consolidated Balance Sheets
Noncurrent assets	$	—		$	4		$	—		$	4		$	—		$	—		$	—		$	—
Current liabilities		—			(1	)		—			(1	)		(5	)		—			(6	)		(1	)
Noncurrent liabilities		(15	)		(67	)		(46	)		(69	)		(50	)		(17	)		(58	)		(17	)

Amounts Recognized in Accumulated Other Comprehensive Income

Amounts recognized in Accumulated other comprehensive income at September 30, 2013 and 2012 were as follows:


	Years Ended September 30
	2013					2012				2013					2012
	Pension Benefits									Postretirement Benefits
	U.S.			Foreign		U.S.		Foreign		U.S.			Foreign		U.S.			Foreign
	(Dollars in millions)
Net actuarial (gain) loss	$	(4	)	$	78	$	29	$	77	$	(3	)	$	3	$	3		$	3
Net prior service cost (credit)		—			—		1		—		(7	)		—		(10	)		—

Balance in accumulated other comprehensive income, pretax	$	(4	)	$	78	$	30	$	77	$	(10	)	$	3	$	(7	)	$	3

Estimated Future Benefit Payments

The Company expects that the following benefit payments will be made to plan participants in the years from 2014 to 2023:


	Pension Benefits				Postretirement Benefits
	U.S.		Foreign		U.S.		Foreign
	(Dollars in millions)
Years Ended:
2014	$	12	$	16	$	5	$	1
2015		11		17		5		1
2016		14		20		5		1
2017		13		19		5		1
2018		12		20		5		1
2019-2023		60		117		20		5

Net Periodic Defined Benefit Pension and Other Postretirement Benefit Costs

Net periodic defined benefit pension and other postretirement benefit costs include the following components:


	Years Ended September 30
	2013						2012						2011						2013					2012					2011
	Pension Benefits																		Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.			Foreign			U.S.			Foreign		U.S.			Foreign		U.S.			Foreign
	(Dollars in millions)
Service cost	$	6		$	9		$	5		$	7		$	5		$	6		$	—		$	—	$	1		$	—	$	1		$	—
Interest cost		6			15			7			11			6			11			2			1		2			1		2			1
Expected return on plan assets		(10	)		(18	)		(9	)		(13	)		(8	)		(13	)		—			—		—			—		—			—
Amortization of prior service cost		—			—			—			—			—			—			(3	)		—		(3	)		—		(3	)		—
Net losses		1			4			1			3			—			3			—			—		—			—		—			—
Settlements or curtailments cost (income)		1			2			1			1			—			—			—			—		(1	)		—		—			—
Other		—			—			—			—			—			2			—			—		—			—		—			—

Net periodic benefit cost	$	4		$	12		$	5		$	9		$	3		$	9		$	(1	)	$	1	$	(1	)	$	1	$	—		$	1

Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, Pre-Tax

Other changes in plan assets and benefit obligations recognized in other comprehensive income, pre-tax are as follows:


	Years Ended September 30
	2013						2012						2011					2013					2012				2011
	Pension Benefits																	Postretirement Benefits
	U.S.			Foreign			U.S.			Foreign			U.S.		Foreign			U.S.			Foreign		U.S.		Foreign		U.S.			Foreign
	(Dollars in millions)
Net (gains) losses	$	(32	)	$	8		$	(3	)	$	27		$	2	$	1		$	(6	)	$	—	$	1	$	1	$	(1	)	$	(1	)
Prior service cost		—			—			(1	)		—			—		—			3			—		1		—		(2	)		—
Amortization of prior service (cost) credit		—			—			—			—			—		—			—			—		3		—		4			—
Amortization of prior unrecognized loss		(2	)		(4	)		(1	)		(3	)		—		(3	)		—			—		—		—		—			—
Other		—			(4	)		—			1			—		—			—			—		—		—		—			—

Total other comprehensive (income) loss	$	(34	)	$	—		$	(5	)	$	25		$	2	$	(2	)	$	(3	)	$	—	$	5	$	1	$	1		$	(1	)

Sensitivity Analysis

A one percentage point change in the 2013 assumed health care cost trend rate would have the following effects:


	1-Percentage-Point
	Increase				Decrease
	U.S.		Foreign		U.S.		Foreign
	(Dollars in millions)
Effect on postretirement benefit obligation	$	—	$	3	$	—	$	(2	)

Defined Benefit Pension Plans Weighted-Average Asset Allocations

The Company’s defined benefit pension plans weighted-average asset allocations at September 30, 2013 and 2012, by asset category are as follows:


	Pension Assets
	September 30
	2013						2012
	U.S.			Foreign			U.S.			Foreign
Asset Category:
Equity securities		63	%		41	%		62	%		39	%
Debt securities		37	%		54	%		38	%		56	%
Cash and other securities		—			5	%		—			5	%

Total		100	%		100	%		100	%		100	%

Fair Value of Pension Plan Assets by Asset Category

The fair value of the Company’s pension plan assets at September 30, 2013 and 2012 by asset category is as follows:


	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)
	2013				Total		2012				Total
Asset Category:
Cash	$	2	$	1	$	3	$	4	$	1	$	5
Direct investments:				—
U.S. equity securities		21		—		21		19		—		19
Non-U.S. equity securities		—		—		—		5		—		5
Non-U.S. government bonds		52		—		52		50		—		50
Non-U.S. corporate bonds		—		—		—		11		—		11

Total direct investments	$	73	$	—	$	73	$	85	$	—	$	85
Investment funds:
Equity funds⁽¹⁾		132		101		233		97		108		205
Fixed income funds⁽²⁾		93		111		204		66		126		192
Real estate funds⁽³⁾		—		1		1		—		2		2
Common and collective investment trust funds⁽⁴⁾		—		1		1		—		—		—
Money market funds		3		—		3		1		—		1
Other		—		—		—		4		—		4

Total investment funds	$	228	$	214	$	442	$	168	$	236	$	404
Alternative investments:
Insurance contracts⁽⁵⁾		—		12		12		—		10		10
Other		—		—		—		—		1		1

Total alternative investments		—	$	12	$	12	$	—	$	11	$	11

Total pension plan assets	$	303	$	227	$	530	$	257	$	248	$	505

⁽¹⁾	The equity funds asset class includes funds that invest in U.S. equities as well as equity securities issued by companies incorporated, listed or domiciled in countries in developed and/or emerging markets. These companies may be in the small-, mid- or large-cap categories.

⁽²⁾

⁽³⁾

⁽⁴⁾

⁽⁵⁾	Insurance contracts held by the Company’s non-U.S. plans are issued by well-known, highly rated insurance companies.

Stock-Based Compensation (Tables)

12 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expenses

The following table presents stock-based compensation expenses included in the Company’s Consolidated Statements of Operations:


	2013			2012			2011
	(Dollars in millions)
Cost of sales	$	4		$	5		$	5
Selling and administrative expenses		7			9			9
Research and technical expenses		1			1			1

Stock-based compensation expense		12			15			15
Income tax benefit		(4	)		(5	)		(5	)

Net stock-based compensation expense	$	8		$	10		$	10

Equity Incentive Plan Activity

The following table summarizes the total stock option, restricted stock, and restricted stock unit activity in the equity incentive plans for fiscal 2013:



	Stock Options							Restricted Stock					Restricted Stock Units
	Total Options			Weighted Average Exercise Price		Weighted Average Grant Date Fair Value		Restricted Stock			Weighted Average Grant Date Fair Value		Restricted Stock Units⁽¹⁾			Weighted Average Grant Date Fair Value
	(Shares in thousands)
Outstanding at September 30, 2012		1,579		$	24.17		$7.37		2		$	9.56		1,231		$	30.28
Granted		301			35.25		12.46		—			—		417			35.28
Performance-based adjustment⁽²⁾		—			—		—		—			—		(142	)		34.43
Exercised / Vested⁽³⁾		(245	)		19.10		4.77		(1	)		9.56		(440	)		23.84
Cancelled / Forfeited		(12	)		32.04		7.30		—			—		(27	)		32.43

Outstanding at September 30, 2013		1,623			26.93		8.71		1			9.56		1,039			34.39

Exercisable at September 30, 2013		1,029			22.63

Exercisable and expected to vest⁽⁴⁾		1,611			26.87

⁽¹⁾	The number “Granted” represents the number of shares issuable upon vesting of time-based restricted stock units and performance-based restricted stock units, assuming the Company performs at the target performance level in each year of the three-year performance period.

⁽²⁾	Represents the incremental number of shares cancelled upon vesting of outstanding performance-based restricted stock units, based on the Company achieving performance at a level less than target under the 2013 performance targets.

⁽³⁾

⁽⁴⁾	Stock options exercisable and expected to vest in the future, net of estimated forfeitures.

Stock Options Outstanding and Vested Options

The following table summarizes information related to the outstanding and vested options on September 30, 2013:


	Total Options Outstanding		Exercisable Options		Exercisable and Expected to Vest
Aggregate Intrinsic Value (in millions)	$	26	$	21	$	26
Weighted Average Remaining Contractual Term (in years)		7.0		6.2		7.0

Weighted-Average Assumptions

The fair values on the grant date were calculated using the following weighted-average assumptions:


	Years Ended September 30
	2013			2012			2011
Expected stock price volatility		46	%		45	%		43	%
Risk free interest rate		0.9	%		1.3	%		1.8	%
Expected life of options (years)		6			6			6
Expected annual dividends per year	$	0.80		$	0.72		$	0.72

Restructuring (Tables)

12 Months Ended

Sep. 30, 2013

Restructuring And Related Activities [Abstract]

Recorded Restructuring Activities

Cabot’s restructuring activities were recorded in the Consolidated Statements of Operations as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Cost of sales	$	28	$	13	$	16
Selling and administrative expenses		7		2		2
Research and technical expenses		2		—		—

Total	$	37	$	15	$	18

Restructuring Activities and Related Reserves

Details of these restructuring activities and the related reserves for fiscal 2013 and 2012 were as follows:


	Severance and Employee Benefits			Environmental Remediation			Asset Impairment and Accelerated Depreciation			Asset Sales			Other			Total
	(Dollars in millions)
Reserve at September 30, 2011	$	9		$	—		$	—		$	—		$	2		$	11
Charges		3			3			7			(1	)		3			15
Costs charged against assets		—			—			(7	)		(3	)		—			(10	)
Proceeds from sale		—			—			—			4			—			4
Cash paid		(10	)		(2	)		—			—			(2	)		(14	)
Foreign currency translation adjustment		—			—			—			—			(1	)		(1	)

Reserve at September 30, 2012	$	2		$	1		$	—		$	—		$	2		$	5
Charges		13			1			19			—			4			37
Costs charged against assets		—			—			(19	)		—			(2	)		(21	)
Cash paid		(8	)		—			—			—			(3	)		(11	)

Reserve at September 30, 2013	$	7		$	2		$	—		$	—		$	1		$	10

Earnings Per Share (Tables)

12 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Components of Basic and Diluted Earnings Per Common Share

The following tables summarize the components of the basic and diluted earnings per common share computations:


	Years Ended September 30
	2013			2012			2011
	(In millions, except per share amounts)
Basic EPS:
Net income attributable to Cabot Corporation	$	153		$	388		$	236
Less: Dividends and dividend equivalents to participating securities		—			—			1
Less: Undistributed earnings allocated to participating securities⁽¹⁾		1			3			2

Earnings allocated to common shareholders (numerator)	$	152		$	385		$	233

Weighted average common shares and participating securities outstanding		64.4			64.0			65.4
Less: Participating securities⁽¹⁾		0.6			0.6			0.8

Adjusted weighted average common shares (denominator)		63.8			63.4			64.6

Per share amounts—basic:
Income from continuing operations attributable to Cabot Corporation	$	2.34		$	2.87		$	2.80
Income from discontinued operations		0.04			3.20			0.82

Net income attributable to Cabot Corporation	$	2.38		$	6.07		$	3.62

Diluted EPS:
Earnings allocated to common shareholders	$	152		$	385		$	233
Plus: Earnings allocated to participating securities		1			3			3
Less: Adjusted earnings allocated to participating securities⁽²⁾		(1	)		(3	)		(3	)

Earnings available to common shares (numerator)	$	152		$	385		$	233

Adjusted weighted average common shares outstanding		63.8			63.4			64.6
Effect of dilutive securities:
Common shares issuable⁽³⁾		0.7			0.8			0.8

Adjusted weighted average common shares (denominator)		64.5			64.2			65.4

Per share amounts—diluted:
Income from continuing operations attributable to Cabot Corporation	$	2.32		$	2.83		$	2.77
Income from discontinued operations		0.04			3.16			0.80

Net income attributable to Cabot Corporation	$	2.36		$	5.99		$	3.57

⁽¹⁾

Calculation of Undistributed Earnings

The calculation of undistributed earnings is as follows:


	Years Ended September 30
	2013		2012		2011
	( Dollars in millions)
Calculation of undistributed earnings:
Net income attributable to Cabot Corporation	$	153	$	388	$	236
Less: Dividends declared on common stock		51		49		46
Less: Dividends and dividend equivalents to participating securities		—		—		1

Undistributed earnings	$	102	$	339	$	189

Allocation of undistributed earnings:
Undistributed earnings allocated to common shareholders	$	101	$	336	$	187
Undistributed earnings allocated to participating securities		1		3		2

Undistributed earnings	$	102	$	339	$	189

⁽²⁾

Undistributed earnings are adjusted for the assumed distribution of dividends to the dilutive securities, which are described in (3) below, and then reallocated to participating securities.

⁽³⁾

Income Taxes (Tables)

12 Months Ended

Sep. 30, 2013

Income Tax Disclosure [Abstract]

Income (Loss) Before Income Taxes

Income (loss) from continuing operations before income taxes and equity in net earnings of affiliated companies was as follows:


	Years ended September 30
	2013		2012		2011
	(Dollars in millions)
Income (loss) from continuing operations:
Domestic	$	35	$	13	$	(25	)
Foreign		170		232		228

Total	$	205	$	245	$	203

Provision (Benefit) for Income Taxes

Tax provision (benefit) for income taxes consisted of the following:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
U.S. federal and state:
Current	$	(3	)	$	(1	)	$	(7	)
Deferred		(8	)		(8	)		(51	)

Total		(11	)		(9	)		(58	)

Foreign:
Current		70			62			57
Deferred		(1	)		2			7

Total		69			64			64

Total U.S. and foreign	$	58		$	55		$	6

Reconciliation Using U.S. Statutory Rate

The provision (benefit) for income taxes differed from the provision for income taxes as calculated using the U.S. statutory rate as follows:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
Computed tax expense at the federal statutory rate	$	72		$	86		$	70
Foreign income:
Impact of taxation at different rates, repatriation and other		(27	)		(29	)		(29	)
Impact of credit for extraordinary repatriation		—			—			(24	)
Impact of investment incentive credits		(1	)		—			(2	)
Impact of foreign losses for which a current tax benefit is not available		9			5			6
Impact of non-deductible net currency losses		18			—			—
U.S. and state benefits from research and experimentation activities		(4	)		(2	)		(3	)
Tax audit settlements		(6	)		(2	)		(12	)
Reversal of state tax valuation allowance		—			(8	)		—
Permanent and other differences		(4	)		5			—
State taxes, net of federal effect		1			—			—

Total	$	58		$	55		$	6

Components of Deferred Income Taxes

Significant components of deferred income taxes were as follows:


	September 30
	2013			2012
	(Dollars in millions)
Deferred tax assets:
Deferred expenses	$	29		$	13
Other		28			36
Pension and other benefits		71			84
Net operating loss carry-forwards		187			194
Foreign tax credit carry-forwards		49			12
R&D credit carry-forwards		28			27
Other business credit carry-forwards		32			31

Subtotal		424			397
Valuation allowances		(166	)		(169	)

Total deferred tax assets	$	258		$	228


	September 30
	2013			2012
	(Dollars in millions)
Deferred tax liabilities:
Intangible assets	$	(28	)	$	(10	)
Inventory		—			(2	)
Property, plant and equipment		(149	)		(141	)
Unremitted earnings of non-U.S. subsidiaries		—			(11	)

Total deferred tax liabilities	$	(177	)	$	(164	)

Expiration Dates of Carryforwards

The following table provides detail surrounding the expiration dates of these carryforwards:


	NOLs		Credits
	(Dollars in millions)
Expiration periods
2014 to 2020	$	391	$	18
2021 and thereafter		83		70
Indefinite carry-forwards		333		20

Total	$	807	$	108

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits for fiscal 2013, 2012 and 2011 is as follows:


	Years ended September 30
	2013			2012			2011
	(Dollars in millions)
Balance at beginning of the year	$	55		$	65		$	75
Additions based on tax provisions related to the current year		1			4			2
Additions for tax positions of prior years		2			—			1
Reductions for tax provisions of prior years		(5	)		(10	)		(2	)
Reductions related to settlements		—			—			(4	)
Reductions from lapse of statute of limitations		(3	)		(4	)		(7	)

Balance at end of the year	$	50		$	55		$	65

Commitments and Contingencies (Tables)

12 Months Ended

Sep. 30, 2013

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Commitments under Non-Cancelable Leases

Future minimum rental commitments under non-cancelable leases are as follows:


	(Dollars in millions)
2014	$	22
2015		18
2016		14
2017		9
2018		8
2019 and thereafter		29

Total future minimum rental commitments	$	100

Schedule of Raw Material Purchased under Long Term Purchase Agreements

Raw materials purchased under these agreements by segment for fiscal 2013, 2012 and 2011 are as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Reinforcement Materials	$	371	$	312	$	340
Performance Materials		34		47		18
Purification Solutions⁽¹⁾		34		4		N/A
Advanced Technologies		—		6		—
Other		2		1		—

Total	$	441	$	370	$	358

⁽¹⁾

The year ended September 30, 2012 includes two months of purchases for Norit.

Schedule of Components of Purchase Commitments


	Payments Due by Fiscal Year
	2014		2015		2016		2017		2018		Thereafter		Total
	(Dollars in millions)
Reinforcement Materials	$	326	$	293	$	226	$	183	$	178	$	2,793	$	3,999
Performance Materials		42		37		33		25		25		226		388
Purification Solutions		28		15		10		10		9		17		89
Advanced Technologies		2		2		1		1		1		1		8

Total	$	398	$	347	$	270	$	219	$	213	$	3,037	$	4,484

Concentration of Credit Risk (Tables)

12 Months Ended

Sep. 30, 2013

Risks And Uncertainties [Abstract]

Schedule of Account Receivable

Tire manufacturers comprise a significant portion of Cabot’s trade receivable balance. The accounts receivable balance for these significant customers as a group are as follows:


	September 30
	2013		2012
	(Dollars in millions)
Tire manufacturers	$	298	$	346

Financial Information by Segment & Geographic Area (Tables)

12 Months Ended

Sep. 30, 2013

Segment Reporting [Abstract]

Schedule of Performance Segment

The net sales from each of these businesses for fiscal 2013, 2012 and 2011 are as follows:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Specialty Carbons and Compounds	$	622	$	664	$	626
Fumed Metal Oxides		282		250		254

Total Performance Materials	$	904	$	914	$	880

Schedule of Advanced Technologies Business Segment

The net sales from each of the Advanced Technologies businesses are as follows::


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Inkjet Colorants	$	64	$	66	$	65
Aerogel		21		18		24
Security Materials		7		9		11
Elastomer Composites		29		23		17
Specialty Fluids		101		94		69

Total Advanced Technologies	$	222	$	210	$	186

Financial Information by Reportable Segment

Financial information by reportable segment is as follows:


	Reinforcement Materials		Performance Materials		Advanced Technologies		Purification Solutions			Segment Total		Unallocated and Other^{(1), (3)}			Consolidated Total
	(Dollars in millions)
Years Ended September 30
2013
Revenues from external customers⁽²⁾	$	1,902	$	904	$	222	$	348		$	3,376	$	87		$	3,463
Depreciation and amortization		81		49		10		54			194		(4	)		190
Equity in earnings of affiliated companies		9		2		—		4			15		(4	)		11
Income (loss) from continuing operations before taxes⁽³⁾		188		132		68		(4	)		384		(179	)		205
Assets⁽⁴⁾		1,512		688		198		1,388			3,786		447			4,233
Total expenditures for additions to long-lived assets⁽⁵⁾		172		46		5		38			261		3			264
2012
Revenues from external customers⁽²⁾	$	2,019	$	914	$	210	$	61		$	3,204	$	96		$	3,300
Depreciation and amortization		82		47		13		8			150		6			156
Equity in earnings of affiliated companies		9		1		—		1			11		—			11
Income (loss) from continuing operations before taxes⁽³⁾		227		128		49		5			409		(164	)		245
Assets⁽⁴⁾		1,527		717		209		1,433			3,886		513			4,399
Total expenditures for additions to long-lived assets⁽⁵⁾		163		87		16		350			616		6			622
2011
Revenues from external customers⁽²⁾	$	1,952	$	880	$	186	$	N/A		$	3,018	$	84		$	3,102
Depreciation and amortization		80		37		14		N/A			131		8			139
Equity in earnings of affiliated companies		7		1		—		N/A			8		—			8
Income (loss) from continuing operations before taxes⁽³⁾		183		140		31		N/A			354		(151	)		203
Assets⁽⁴⁾		1,509		661		191		N/A			2,361		780			3,141
Total expenditures for additions to long-lived assets⁽⁵⁾		126		99		10		N/A			235		6			241

⁽¹⁾	Unallocated and other includes certain items and eliminations necessary to reflect management’s reporting of operating segment results. These items are reflective of the segment reporting presented to the Chief Operating Decision Maker.

⁽²⁾	Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, the impact of the corporate adjustment for unearned revenue and Notes receivable. See table below:


	Years Ended September 30
	2013		2012		2011
	(Dollars in millions)
Royalties paid by equity affiliates, other operating revenues, the impact of the corporate adjustment for unearned revenue, unconsolidated equity affiliates and discounting charges for certain Notes Receivable	$	5	$	11	$	(2	)
Shipping and handling fees		82		85		86

Total	$	87	$	96	$	84

⁽³⁾	Income (loss) from continuing operations before taxes for Unallocated and Other includes:


	Years Ended September 30
	2013			2012			2011
	(Dollars in millions)
Interest expense	$	(62	)	$	(46	)	$	(39	)
Total certain items, pre-tax^(a)		(56	)		(51	)		(19	)
Equity in earnings of affiliated companies, net of tax^(b)		(11	)		(11	)		(8	)
Unallocated corporate costs^(c)		(49	)		(56	)		(53	)
General unallocated expense^(d)		(1	)		—			(32	)

Total	$	(179	)	$	(164	)	$	(151	)

^(a)

^(b)

Equity in earnings of affiliated companies, net of tax, is included in Segment EBIT and is removed from Unallocated and other to reconcile to income (loss) from operations before taxes.

^(c)

Unallocated corporate costs are not controlled by the segments and primarily benefit corporate interests.

^(d)

⁽⁴⁾	Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters’ assets, and current and non-current assets held for sale.

⁽⁵⁾	Expenditures for additions to long-lived assets include total equity and other investments (including available-for-sale securities) and property, plant and equipment.

Revenues from External Customers and Long-Lived Asset Information by Geographic Area

Revenues from external customers and long-lived asset information by geographic area are summarized as follows:


	United States		China		Netherlands		Other Foreign Countries		Consolidated Total
	(Dollars in millions)
Years Ended September 30,
2013
Revenues from external customers	$	825	$	558	$	224	$	1,856	$	3,463
Net property, plant and equipment	$	493	$	385	$	211	$	516	$	1,605
2012
Revenues from external customers	$	695	$	543	$	131	$	1,931	$	3,300
Net property, plant and equipment	$	486	$	305	$	208	$	553	$	1,552
2011
Revenues from external customers	$	589	$	554	$	115	$	1,844	$	3,102
Net property, plant and equipment	$	233	$	274	$	45	$	484	$	1,036

Unaudited Quarterly Financial Information (Tables)

12 Months Ended

Sep. 30, 2013

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

Unaudited financial results by quarter for fiscal 2013 and 2012 are summarized below:


	Quarter Ended
	December			March			June			September			Year
	(Dollars in millions, except per share amounts)
Fiscal 2013
Consolidated Net Income
Net sales and other operating revenues	$	820		$	842		$	903		$	898		$	3,463

Gross profit		147			144			177			168			636
Selling and administrative expenses		73			77			73			76			299
Research and technical expenses		19			18			18			19			74

Income from operations		55			49			86			73			263
Net interest expense and other charges		(14	)		(13	)		(13	)		(18	)		(58	)

Income from continuing operations before income taxes and equity in earnings of affiliated companies		41			36			73			55			205
Provision for income taxes		(19	)		(16	)		(16	)		(7	)		(58	)
Equity in earnings of affiliated companies, net of tax		3			3			3			2			11
Income from discontinued operations, net of tax		(1	)		—			2			1			2

Net income		24			23			62			51			160
Net income attributable to noncontrolling interests, net of tax		4			(4	)		3			4			7

Net income attributable to Cabot Corporation	$	20		$	27		$	59		$	47		$	153

Income per share—basic:
Income from continuing operations	$	0.33		$	0.43		$	0.86		$	0.72		$	2.34
Income from discontinued operations		(0.02	)		—			0.04			0.02			0.04

Net income attributable to Cabot Corporation	$	0.31		$	0.43		$	0.90		$	0.74		$	2.38

Income per share—diluted:
Income from continuing operations	$	0.33		$	0.42		$	0.86		$	0.71		$	2.32
Income from discontinued operations		(0.02	)		—			0.04			0.02			0.04

Net income attributable to Cabot Corporation	$	0.31		$	0.42		$	0.90		$	0.73		$	2.36


	Quarter Ended
	December			March			June			September			Year
	(Dollars in millions, except per share amounts)
Fiscal 2012
Consolidated Net Income
Net sales and other operating revenues	$	762		$	844		$	846		$	848		$	3,300

Gross profit		143			173			175			157			648
Selling and administrative expenses		65			66			68			86			285
Research and technical expenses		17			20			17			19			73

Income from operations		61			87			90			52			290
Net interest expense and other charges		(6	)		(11	)		(12	)		(16	)		(45	)

Income from continuing operations before taxes and equity earnings of affiliated companies		55			76			78			36			245
Provision for income taxes		(16	)		(23	)		(16	)		—			(55	)
Equity in earnings of affiliated companies		1			3			4			3			11
Income from discontinued operations, net of tax		11			189			4			1			205

Net income		51			245			70			40			406
Net income attributable to noncontrolling interests, net of tax		5			5			4			4			18

Net income attributable to Cabot Corporation	$	46		$	240		$	66		$	36		$	388

Income per share—basic:
Income from continuing operations	$	0.55		$	0.80		$	0.97		$	0.55		$	2.87
Income from discontinued operations		0.17			2.94			0.07			0.02			3.20

Net income attributable to Cabot Corporation	$	0.72		$	3.74		$	1.04		$	0.57		$	6.07

Income per share—diluted:
Income from continuing operations	$	0.55		$	0.78		$	0.96		$	0.54		$	2.83
Income from discontinued operations		0.16			2.92			0.06			0.02			3.16

Net income attributable to Cabot Corporation	$	0.71		$	3.70		$	1.02		$	0.56		$	5.99

Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, ¥ in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2013	Sep. 30, 2013 USD ($) Customer $ / shares	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2013 CNY (¥)	Sep. 30, 2012 CNY (¥)	Sep. 30, 2010 USD ($)
Significant Accounting Policies [Line Items]
Maturity period of highly liquid investments		3 months
Equity affiliate investments		$ 119	$ 115
Dividends declared		8	6	$ 4
Increase in income from continuing operations, expected		$ 9
Increase in diluted common share, expected \| $ / shares		$ 0.14
Increase in income from continuing operations, estimated		$ 4
Increase in diluted common share, estimated \| $ / shares		$ 0.06
Capitalized interest		$ 5	4	2
Goodwill		504	480	40
Asset retirement obligation reserve		16	18
Other asset retirement obligation		1
Reduction in ARO liability		$ 2
Revenue recognized due, description		2022
Number of customer having licensing agreements \| Customer		1
Royalty and technology payments		$ 9
Charges on sale of notes receivables		4	2
Changes in allowance		3
Notes receivable from sale of business		214	252
Contractual due payment		$ 215
Due date of contractual payment		Mar. 31, 2014			Mar. 31, 2014
Impairment recorded		$ 0	0
Uncertain tax positions tax benefit recognized subject to threshold limit		$ 50	55	65			$ 75
Chance of utilizing the associated benefit for valuation allowances, maximum		50.00%
Norit [Member]
Significant Accounting Policies [Line Items]
Asset retirement obligation reserve			10
Purification Solutions [Member]
Significant Accounting Policies [Line Items]
Goodwill		$ 466
Service Life [Member]
Significant Accounting Policies [Line Items]
Change in income from continue operations		The change increased Income from continuing operations by $4 million ($0.06 per diluted common share)
Scenario, Forecast [Member] \| Service Life [Member]
Significant Accounting Policies [Line Items]
Change in income from continue operations		The Company expects the change will increase Income from continuing operations by $9 million ($0.14 per diluted common share)
Notes Receivable [Member]
Significant Accounting Policies [Line Items]
Accounts and notes receivable, net		$ 24	24		¥ 148	¥ 155
Other Expense [Member]
Significant Accounting Policies [Line Items]
Foreign currency transaction gains (losses)		$ 2	$ (2)	(6)
Machinery and Equipment [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment	25 years
Machinery and Equipment [Member] \| Service Life [Member]
Significant Accounting Policies [Line Items]
Change in accounting estimate description	The Company changed the estimated depreciable lives of certain machinery and equipment from ten to twenty-five years to reflect the Company's experience.
Machinery and Equipment [Member] \| Previous Estimate [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment	10 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Investments in equity affiliates		50.00%			50.00%
Charges on sale of notes receivables				$ 1
Maximum [Member] \| Buildings [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		25 years
Maximum [Member] \| Machinery and Equipment [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		25 years
Maximum [Member] \| Other Fixed Assets [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		25 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Investments in equity affiliates		20.00%			20.00%
Minimum [Member] \| Buildings [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		20 years
Minimum [Member] \| Machinery and Equipment [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		10 years
Minimum [Member] \| Other Fixed Assets [Member]
Significant Accounting Policies [Line Items]
Useful life of property, plant and equipment		3 years

Significant Accounting Policies - Segment Reporting Revenue Percentage (Detail)

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Reinforcement Materials [Member]

56.00%

63.00%

65.00%

Advanced Technologies [Member]

27.00%

28.00%

29.00%

Purification Solutions [Member]

7.00%

6.00%

^[1]

10.00%

2.00%

[1]	Fiscal 2012 includes two months of revenue for Purification Solutions, which the Company acquired on July 31, 2012.

Significant Accounting Policies - Accumulated Other Comprehensive Items in Accompanying Balance Sheet (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Foreign currency translation adjustment at beginning of year	$ 167	$ 163
Net foreign currency translation adjustments	(13)	4
Foreign currency translation adjustment at end of year	154	167
Unrealized gain on investments and derivative instruments at beginning of year		1
Net unrealized gains	2	(1)
Unrealized gain on investments and derivative instruments at end of year	2
Pension and other postretirement benefit plans at beginning of year	(75)	(58)
Net change in pension and other postretirement benefit plans	22	(17)
Pension and other postretirement benefit plans at end of year	(53)	(75)
Total accumulated other comprehensive income	$ 103	$ 92

Goodwill And Other Intangible Asset [Line Items]

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Acquisitions - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Nov. 15, 2013	Jul. 31, 2012	Sep. 30, 2013	Jun. 30, 2013
Business Acquisition [Line Items]
Acquisition paying		$ 1,100
Fair value of the assets acquired includes trade receivables			$ 46
NHUMO [Member]
Business Acquisition [Line Items]
Percentage acquisition				60.00%
Acquisition date			Nov. 15, 2013
Subsequent Event [Member] \| NHUMO [Member]
Business Acquisition [Line Items]
Cash paid on acquisition	$ 80
Preferred stock redemption amount	$ 25
Dividend percentage of preferred stock	6.00%
Preferred stock issued on acquisition	$ 25
Trademarks, Indefinite Lives [Member]
Business Acquisition [Line Items]
Intangible assets			$ 57
Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets			$ 110
Amortized period			18 years
Developed Technology [Member]
Business Acquisition [Line Items]
Intangible assets			$ 150
Amortized period			20 years

Acquisitions - Components and Allocation of Purchase Price (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Business Acquisition [Line Items]
Goodwill	$ 504	$ 480	$ 40
Norit N.V. [Member]
Business Acquisition [Line Items]
Current assets	203	207
Property, plant and equipment	371	385
Other non-current assets	76	72
Intangible assets	317	325
Goodwill	454	432
Current liabilities	(98)	(98)
Deferred non-current tax liabilities	(172)	(176)
Other non-current liabilities	(38)	(34)
Total purchase price	1,113	$ 1,113
Norit N.V. [Member] \| Measurement Period Adjustments [Member]
Business Acquisition [Line Items]
Current assets	(4)
Property, plant and equipment	(14)
Other non-current assets	4
Intangible assets	(8)
Goodwill	22
Deferred non-current tax liabilities	4
Other non-current liabilities	$ (4)

Acquisitions - Pro Forma Net Sales and Results of Operations (Detail) $ in Millions	12 Months Ended
	Sep. 30, 2012 USD ($)
Business Combinations [Abstract]
Net sales	$ 3,585
Income from continuing operations	$ 209

Discontinued Operations - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total consideration from sale of business	$ 452.0
Cash payment, transactions closes	175.0
Notes receivable received on sale of discontinued operations	$ 277.0
GAM promissory notes and inventory note, final maturity date	2014-03
Percentage of quarterly cash payments receivable of adjusted EBITDA	50.00%
Minimum payment guaranteed on sale of discontinued operation	$ 11.5
Promissory note included in other asset section			$ 242.0
Company received payment under the GAM Notes		$ 39.0	23.0
After-tax gain (loss) on the sale of discontinued operations		2.0	191.0
Tax benefit on discontinued operations		4.0
Adjustment of tax effect from gain loss of prior period on discontinued operations		$ (2.0)
Settlements net charges			$ 0.0
Period of supply agreement		3 years
Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Settlements net charges		$ 1.0		$ (1.0)
GAM Notes [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Promissory note included in other asset section		214.0
Company received payment under the GAM Notes		$ 62.0

Discontinued Operations - Components of Discontinued Operations (Detail) - USD ($) $ in Millions	3 Months Ended							12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Discontinued Operations And Disposal Groups [Abstract]
Net sales and other operating revenues									$ 46	$ 201
Income from operations before income taxes									21	84
Provision for income taxes on operations									(7)	(31)
Income from operations, net of tax									14	53
(Loss) Gain on sale of discontinued operations								$ (2)	300
Benefit from (Provision for) income taxes on gain (loss) on sale								4	(109)
Gain on sale of discontinued operations, net of tax								2	191
Income from discontinued operations, net of tax	$ 1	$ 2	$ (1)	$ 1	$ 4	$ 189	$ 11	$ 2	$ 205	$ 53

Inventories - Components of Company's Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Inventory Disclosure [Abstract]
Raw materials	$ 102	$ 131
Work in process	2	5
Finished goods	310	351
Other	44	46
Total	$ 458	$ 533

Inventories - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Inventory Disclosure [Abstract]
Inventory valued under the LIFO method	5.00%	5.00%
Inventory, LIFO reserve	$ 55	$ 52
Decrease in cost of goods sold	1	1	$ 0
Effect of LIFO inventory liquidation on income	$ 1	$ 1	$ 0
Liquidation of LIFO inventory, resulted per diluted common share	$ 0.01	$ 0.01	$ 0.00
Obsolete inventory reserve	$ 15	$ 15

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property Plant And Equipment [Abstract]
Land and land improvements	$ 138	$ 167
Buildings	511	495
Machinery and equipment	2,511	2,379
Other	238	226
Construction in progress	278	244
Total property, plant and equipment	3,676	3,511
Less: accumulated depreciation	(2,071)	(1,959)
Net property, plant and equipment	$ 1,605	$ 1,552	$ 1,036

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Property Plant And Equipment [Abstract]
Depreciation expense	$ 176	$ 153	$ 138

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Goodwill And Intangible Assets [Line Items]
Goodwill		$ 504	$ 480	$ 40
Goodwill annual impairment	$ 0
Amortization expense estimated for year one		14
Amortization expense estimated for year two		14
Amortization expense estimated for year three		14
Amortization expense estimated for year four		14
Amortization expense estimated for year five		14
Asset impairment charges	$ 0
Cost of Sales and Selling and Administrative Expenses [Member]
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets		$ 14	$ 3
Maximum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets		20 years
Maximum [Member] \| Cost of Sales [Member]
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets				$ 1
Minimum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets		6 years
Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets		19 years

Goodwill and Other Intangible Assets - Schedule of Goodwill Balances (Detail) - USD ($)
$ in Millions

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Measurement period adjustments

$ 480

$ 40

^[1]

Goodwill acquired

432

Foreign currency translation adjustment

Reinforcement Materials [Member]

504

480

Goodwill And Other Intangible Asset [Line Items]

Foreign currency translation adjustment

(3)

Goodwill And Other Intangible Asset [Line Items]

Advanced Technologies [Member]

Goodwill And Other Intangible Asset [Line Items]

Purification Solutions [Member]

Goodwill And Other Intangible Asset [Line Items]

Measurement period adjustments

439

^[1]

Goodwill acquired

432

Foreign currency translation adjustment

Goodwill And Other Intangible Assets [Line Items]

$ 466

$ 439

[1]	Refer to Note C for further details related to the measurement period adjustments.

Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($)
$ in Millions

Sep. 30, 2013

Sep. 30, 2012

$ 271

$ 278

Gross Carrying Value

328

336

(18)

(6)

Trademarks, Indefinite Lives [Member]

253

272

Net Intangible Assets

310

330

Goodwill And Other Intangible Assets [Line Items]

Developed Technology [Member]

Goodwill And Other Intangible Assets [Line Items]

155

151

(9)

(2)

Customer Relationships [Member]

146

149

Goodwill And Other Intangible Assets [Line Items]

^[1]

113

121

^[1]

(7)

(1)

Other Intangible Assets [Member]

^[1]

106

120

Goodwill And Other Intangible Assets [Line Items]

(2)

(3)

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

$ 1

$ 3

[1]	The change in the gross carrying value of the Customer relationships intangible asset is primarily due to measurement period adjustments as described in Note C.

Accounts Payable, Accrued Liabilities and Other Liabilities - Components of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Payables And Accruals [Abstract]
Accounts payable	$ 398	$ 425
Accrued employee compensation	41	46
Other accrued liabilities	95	135
Total	$ 534	$ 606

Accounts Payable, Accrued Liabilities and Other Liabilities - Components of Other Long-Term Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Payables And Accruals [Abstract]
Employee benefit plan liabilities	$ 149	$ 190
Non-current tax liabilities	47	53
Financial instrument liabilities		26
Other accrued liabilities	69	45
Total	$ 265	$ 314

Debt and Other Obligations - Schedule of Long-Term Obligations (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012	Jul. 31, 2012	Sep. 30, 2009	Dec. 31, 2003
Debt Instrument [Line Items]
Capital lease obligations, due through 2031	$ 18	$ 16
Unamortized debt discount	(2)	(2)	$ (1)
Total debt	1,034	1,357
Less current portion of long-term debt	(14)	(185)
Total long-term debt	1,020	1,172
Variable Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	47	200
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	971	1,143
Total Medium Term Notes	53	53
Revolving Credit Facility Expiry August 2016 [Member] \| Variable Rate Debt [Member]
Debt Instrument [Line Items]
Total debt		189
Chinese Renminbi Notes, Due Through 2016, 5.40% - 6.77% [Member] \| Variable Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	47	11
5% Notes Due 2017 [Member]
Debt Instrument [Line Items]
Unamortized debt discount				$ (2)
5% Notes Due 2017 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	300	300
2.55% Notes Due 2018 [Member]
Debt Instrument [Line Items]
Unamortized debt discount			$ (1)
2.55% Notes Due 2018 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	250	250
3.7% Notes Due 2022 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	350	350
Notes Due 2019, 7.42% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total Medium Term Notes	30	30
Notes Due 2022, 8.346% - 8.47% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total Medium Term Notes	15	15
Note Due 2028, 6.57% - 7.28% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total Medium Term Notes	8	8
Eurobond, Due 2013, 5.25% [Member]
Debt Instrument [Line Items]
Unamortized debt discount					$ (1)
Eurobond, Due 2013, 5.25% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt		177
Guarantee Of Employee Stock Option Plan Note Due On Two Thousand And Fourteen [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	2	8
Chinese Renminbi Notes, Due Through 2018, 4.68% - 6.65% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Total debt	16	5
Capital Lease Obligations, Due Through 2031 [Member]
Debt Instrument [Line Items]
Capital lease obligations, due through 2031	$ 18	$ 16

Debt and Other Obligations - Schedule of Long-Term Obligations (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jul. 31, 2012	Sep. 30, 2009	Dec. 31, 2003
Revolving Credit Facility Expiry August 2016 [Member]
Debt Instrument [Line Items]
Debt instrument due, year	1.304%
Capital Lease Obligations, Due Through 2031 [Member]
Debt Instrument [Line Items]
Debt instrument maturity, maximum range	2031	2031
Variable Rate Debt [Member] \| Revolving Credit Facility Expiry August 2016 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 750
Debt instrument due, year		2016
Variable Rate Debt [Member] \| Chinese Renminbi Notes, Due Through 2016, 5.40% - 6.77% [Member]
Debt Instrument [Line Items]
Debt instrument due, year	5.40%	5.40%
Debt instrument interest rate, maximum	6.77%	6.77%
Debt instrument maturity, maximum range	2016	2016
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument due, year			3.70%
Debt instrument due, year	2022
Fixed Rate Debt [Member] \| 5% Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt instrument due, year	5.00%	5.00%		5.00%
Debt instrument due, year	2017	2017
Fixed Rate Debt [Member] \| 2.55% Notes Due 2018 [Member]
Debt Instrument [Line Items]
Debt instrument due, year	2.55%	2.55%	2.55%
Debt instrument due, year	2018	2018
Fixed Rate Debt [Member] \| 3.7% Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt instrument due, year	3.70%	3.70%
Debt instrument due, year	2022	2022
Fixed Rate Debt [Member] \| Notes Due 2019, 7.42% [Member]
Debt Instrument [Line Items]
Debt instrument due, year	7.42%	7.42%
Debt instrument due, year	2019	2019
Fixed Rate Debt [Member] \| Notes Due 2022, 8.346% - 8.47% [Member]
Debt Instrument [Line Items]
Debt instrument due, year	8.346%	8.346%
Debt instrument interest rate, maximum	8.47%	8.47%
Debt instrument due, year	2022	2022
Fixed Rate Debt [Member] \| Note Due 2028, 6.57% - 7.28% [Member]
Debt Instrument [Line Items]
Debt instrument due, year	6.57%	6.57%
Debt instrument interest rate, maximum	7.28%	7.28%
Debt instrument due, year	2028	2028
Fixed Rate Debt [Member] \| Eurobond, Due 2013, 5.25% [Member]
Debt Instrument [Line Items]
Debt instrument due, year		5.25%			5.25%
Debt instrument due, year	2013	2013
Fixed Rate Debt [Member] \| Guarantee Of Employee Stock Option Plan Note Due On Two Thousand And Fourteen [Member]
Debt Instrument [Line Items]
Debt instrument due, year	8.29%	8.29%
Debt instrument due, year	2014	2014
Fixed Rate Debt [Member] \| Chinese Renminbi Notes, Due Through 2018, 4.68% - 6.65% [Member]
Debt Instrument [Line Items]
Debt instrument due, year	4.68%	4.68%
Debt instrument interest rate, maximum	6.65%	6.65%
Debt instrument due, year	2018	2018

Debt and Other Obligations - Additional Information (Detail) - USD ($)	1 Months Ended			12 Months Ended
	Jan. 31, 2013	Jul. 31, 2012	Nov. 30, 1988	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2009	Dec. 31, 2003
Debt Instrument [Line Items]
Current maximum size of revolving credit facility	$ 750,000,000
Long-term debt				$ 1,034,000,000	$ 1,357,000,000
Public notes issued		$ 350,000,000
Issuance of notes, discount recorded		$ 1,000,000		2,000,000	2,000,000
Proceeds from issuance of debt notes				347,000,000
Funds borrowed to purchase of Cabot shares				117,000,000	911,000,000
Dividends paid to ESOP				2,000,000	2,000,000	$ 2,000,000
Interest payments from ESOP					1,000,000	1,000,000
Capital lease obligations				18,000,000	16,000,000
Repayments of long-term capital lease obligations				$ 42,000,000
Repayment period of capital lease obligation, years				18 years
Payment towards imputed interest				$ 12,000,000
Original cost of capital lease assets				24,000,000	26,000,000
Accumulated depreciation of assets under capital leases				9,000,000	11,000,000
Unsecured short term notes payable to bank				$ 264,000,000	$ 62,000,000
Weighted-average interest rate				0.70%	5.20%
Commercial paper notes outstanding				$ 264,000,000	$ 62,000,000
Maximum [Member]
Debt Instrument [Line Items]
Interest payments from ESOP				1,000,000
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate		3.70%
Long-term debt				$ 971,000,000	1,143,000,000
Debt instrument due, year				2022
Unsecured medium term notes outstanding issued				$ 53,000,000	53,000,000
Maturity of the total outstanding medium term notes, years				8 years
Weighted average interest of medium term notes				7.65%
Commercial Paper [Member]
Debt Instrument [Line Items]
Weighted-average interest rate				0.32%
Maturity period of commercial paper	364 days			28 days
Commercial paper notes outstanding				$ 241,000,000
Chinese Renminbi Notes [Member]
Debt Instrument [Line Items]
Long-term debt				63,000,000	$ 16,000,000
Revolving Credit Facility Expiry August 2016 [Member]
Debt Instrument [Line Items]
Current maximum size of revolving credit facility				$ 750,000,000
Revolving credit facility, agreement period				Aug. 31, 2016
Interest rates are based upon LIBOR plus a spread, spread				1.125%
Debt instrument, interest rate				1.304%
Line of credit facility outstanding				$ 0
Letters of credit and commercial paper outstanding				$ 508,000,000
5% Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt maturity date				Oct. 01, 2016
Public notes issued							$ 300,000,000
Issuance of notes, discount recorded							$ 2,000,000
Proceeds from issuance of debt notes				$ 296,000,000
5% Notes Due 2017 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate				5.00%	5.00%		5.00%
Long-term debt				$ 300,000,000	$ 300,000,000
Debt instrument due, year				2017	2017
2.55% Notes Due 2018 [Member]
Debt Instrument [Line Items]
Debt maturity date				Jan. 15, 2018
Public notes issued		$ 250,000,000
Issuance of notes, discount recorded		$ 1,000,000
Proceeds from issuance of debt notes				$ 248,000,000
2.55% Notes Due 2018 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate		2.55%		2.55%	2.55%
Long-term debt				$ 250,000,000	$ 250,000,000
Debt instrument due, year				2018	2018
3.7% Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt maturity date				Jul. 15, 2022
3.7% Notes Due 2022 [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate				3.70%	3.70%
Long-term debt				$ 350,000,000	$ 350,000,000
Debt instrument due, year				2022	2022
Eurobond, Due 2013, 5.25% [Member]
Debt Instrument [Line Items]
Issuance of notes, discount recorded								$ 1,000,000
Proceeds from issuance of debt notes								$ 175,000,000
Eurobond, Due 2013, 5.25% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate					5.25%			5.25%
Long-term debt					$ 177,000,000
Debt instrument due, year				2013	2013
ESOP Note, Due 2013, 8.29% [Member]
Debt Instrument [Line Items]
Long-term debt				$ 2,000,000	$ 8,000,000
Debt maturity date				Dec. 31, 2013
Funds borrowed to purchase of Cabot shares			$ 75,000,000
Employer contribution to ESOP to service the debt				$ 4,000,000	$ 5,000,000	$ 4,000,000
ESOP Note, Due 2013, 8.29% [Member] \| Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate				8.29%
Debt instrument due, year				2013
Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Debt instrument due, year				2014
Standby letters of credit, outstanding amount				$ 10,000,000

Debt and Other Obligations - Schedule of Future Years Payment (Detail) $ in Millions	Sep. 30, 2013 USD ($)
Future Years Payment [Line Items]
2014	$ 17
2015	34
2016	14
2017	303
2018	265
Thereafter	427
Less: executory costs and interest	(24)
Total	1,036
Principal Payments on Long Term Debt [Member]
Future Years Payment [Line Items]
2014	12
2015	30
2016	11
2017	300
2018	262
Thereafter	403
Total	1,018
Capital Lease Obligations, Due Through 2031 [Member]
Future Years Payment [Line Items]
2014	5
2015	4
2016	3
2017	3
2018	3
Thereafter	24
Less: executory costs and interest	(24)
Total	$ 18

Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, liabilities, Level 2 to Level 1 transfers, amount	$ 0	$ 0
Fair value, assets, Level 2 to Level 1 transfers, amount	0	0
Fair value, liabilities, Level 1 to Level 2 transfers, amount	0	0
Fair value, assets, Level 1 to Level 2 transfers, amount	0	0
Fair value, assets, transfers into Level 3, amount	0	0
Fair value, assets, transfers out of Level 3, amount	0	0
Fair value, liabilities, transfers into Level 3, amount	0	0
Fair value, liabilities, transfers out of Level 3, amount	0	0
Notes receivable from sale of business	214	252
Contractual due payment	$ 215
Due date of contractual payment	Mar. 31, 2014
GAM notes fair value	$ 205	252
Fair value of long-term debt	1,010	1,420
Fixed Rate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of long-term debt	$ 970	$ 1,140

Financial Instruments and Fair Value Measurements - Schedule of Fair Value of Derivatives, Net of Legal Right to Offset Derivative Settlements (Detail) - Significant Observable Inputs (Level 2) [Member] - USD ($)
$ in Millions

Sep. 30, 2013

Sep. 30, 2012

Guaranteed investment contract

^[1]

$ 14

Derivatives relating to interest rates

^[2]

Total assets at fair value

$ 14

Derivatives relating to foreign currency

^[2]

Hedged long-term debt

^[3]

Total liabilities at fair value

$ 64

[1]	Included in "Other assets" in the Consolidated Balance Sheets.
[2]	Included in "Prepaid expenses and other current assets", "Other assets", "Accounts payable and accrued liabilities" or "Other liabilities" in the Consolidated Balance Sheets.
[3]	Included in "Current portion of long-term debt" in the fiscal 2012 Consolidated Balance Sheets.

Derivatives - Additional Information (Detail) - USD ($)	12 Months Ended
Derivatives - Additional Information (Detail) - USD ($)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Derivative [Line Items]
Significant concentration of credit risk associated with our derivative instruments	$ 0
Gain (loss) on foreign currency derivatives recorded in earnings	4,000,000	$ (10,000,000)	$ (2,000,000)
Bond held by one of Cabot's European subsidiaries	175,000,000	175,000,000	175,000,000
Fair Value Hedging [Member] \| Interest Rate Swap-Fixed to Variable [Member]
Derivative [Line Items]
Derivatives held to manage interest rate risk	0
Currency Swaps [Member]
Derivative [Line Items]
Gain (loss) on foreign currency derivative instruments not designated as hedging instruments	(2,000,000)	12,000,000	1,000,000
Forward Foreign Currency Contracts [Member]
Derivative [Line Items]
Gain (loss) on foreign currency derivative instruments not designated as hedging instruments	$ 5,000,000	$ 10,000,000	$ 3,000,000

Derivatives - Schedule of Derivatives Fair Value Interest Rate (Detail) - USD ($)

Sep. 30, 2013

Sep. 30, 2012

Eurobond 20% [Member]

Fair Value Hedging [Member] | Interest Rate Swap-Fixed to Variable [Member]

$ 175,000,000

Notional amount of interest rate fair value hedge derivatives

$ 0

Fair Value Hedging [Member] | Interest Rate Swap-Fixed to Variable [Member] | Eurobond 20% [Member]

Percentage of debt hedged by interest rate derivatives

^[1]

20.00%

Notional amount of interest rate fair value hedge derivatives

^[1]

$ 175,000,000

^[1]

$ 35,000,000

[1]	In September 2013, the Company settled the Eurobond and related foreign currency and interest rate swaps.

Derivatives - Foreign Currency Risk Management (Detail)
€ in Millions, $ in Millions

Sep. 30, 2013

USD ($)

Sep. 30, 2012

USD ($)

Sep. 30, 2012

EUR (€)

Eurobond 80% [Member]

Percentage of debt hedged by cross currency swaps

$ 175

80.00%

Eurobond 20% [Member]

Percentage of debt hedged by cross currency swaps

$ 175

20.00%

Not Designated as Hedging Instrument [Member] | Eurobond 80% [Member]

Notional amount of foreign currency derivative instruments not designated as hedging instruments

$ 140

€ 124

Not Designated as Hedging Instrument [Member] | Eurobond 20% [Member]

Notional amount of foreign currency derivative instruments not designated as hedging instruments

€ 31

Not Designated as Hedging Instrument [Member] | Forward Foreign Currency Contracts [Member]

Notional amount of foreign currency derivative instruments not designated as hedging instruments

^[1]

$ 31

106

Cash Flow Hedging [Member] | Forward Foreign Currency Contracts [Member]

Notional amount of foreign currency derivative instruments not designated as hedging instruments

^[1]

$ 3

[1]	Cabot's forward foreign exchange contracts are denominated primarily in the Australian dollar, British pound sterling, Canadian dollar, Chinese renminbi, Czech koruna, Euro, Indian rupee and Japanese yen.

Derivatives - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($)
$ in Millions

Sep. 30, 2013

Sep. 30, 2012

Total Asset Derivatives

$ 3

Designated as Hedging Instrument [Member] | Accounts Payable and Accrued Liabilities [Member] | Interest Rate [Member]

Not Designated as Hedging Instrument [Member]

Total Asset Derivatives

^[1]

Not Designated as Hedging Instrument [Member] | Prepaid Expenses and Other Current Assets [Member] | Other [Member]

Total Asset Derivatives

^[2]

Not Designated as Hedging Instrument [Member] | Accounts Payable and Accrued Liabilities, and Other Liabilities [Member] | Foreign Currency [Member]

^[2]

^[1]

$ 28

[1]	Contracts of $2 million presented on a gross basis in this table at September 30, 2012 have the legal right to offset against other types of contracts with a common counterparty and, therefore, are presented on a net basis in "Accounts payable and accrued liabilities" in the Consolidated Balance Sheet.
[2]	Contracts in fiscal 2012 an asset and liability position presented on a gross basis in this table have the legal right of offset and, therefore, are presented on a net basis in "Prepaid expenses and other current assets" in the Consolidated Balance Sheets.

Derivatives - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Parenthetical) (Detail) $ in Millions	Sep. 30, 2012 USD ($)
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Interest rate contracts with right of offset	$ 2

Venezuela - Additional Information (Detail) $ in Millions, in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2013 VEF ( )	Sep. 30, 2012 USD ($)	Sep. 30, 2012 VEF ( )	Sep. 30, 2011 USD ($)	Sep. 30, 2013 VEF ( )	Feb. 28, 2013 / shares
Nature Of Operations [Line Items]
Operating affiliate investment		$ 25
Due from affiliates, dividends cash		3					20
Currency devaluation, remeasurement loss	$ 2
Tax benefit due to reduction of deferred tax liablities		(9)		$ (6)		$ (25)
Cash dividends received		$ 3	15	$ 6	27
Minimum [Member]
Nature Of Operations [Line Items]
Equity method investment, ownership percentage		20.00%					20.00%
Maximum [Member]
Nature Of Operations [Line Items]
Equity method investment, ownership percentage		50.00%					50.00%
Devaluation of the Bolivar [Member] \| Minimum [Member]
Nature Of Operations [Line Items]
Devaluation of bolivar to USD \| / shares								4.3
Devaluation of the Bolivar [Member] \| Maximum [Member]
Nature Of Operations [Line Items]
Devaluation of bolivar to USD \| / shares								6.3
Operating Affiliate, Venezuela [Member]
Nature Of Operations [Line Items]
Equity method investment, ownership percentage		49.00%					49.00%
Tax benefit due to reduction of deferred tax liablities		$ 1
Operating Affiliate [Member]
Nature Of Operations [Line Items]
Currency devaluation, remeasurement loss		1
Tax impact on devaluation		1
Equity in earnings of affiliated companies		$ 1

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans, expenses not related to ESOP		$ 9	$ 7	$ 7
Percentage of company funded under ESOP		100.00%
Shares allocated under ESOP		108,696.645
Compensation expense related to the ESOP		$ 4	5	4
Amortization of estimated prior service credits		3
Curtailments gain (loss)		(3)	(1)	$ 1
Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss amortized from accumulated other comprehensive income to net periodic benefit cost	$ 3
U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		$ 170	187
Weighted-average assumed health care cost trend rate		8.00%
Ultimate weighted-average health care cost trend rate		7.50%
Ultimate weighted-average health care cost trend rate, anticipated achievement year		2018
U.S. Defined Benefit Plans [Member] \| Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		65.00%
U.S. Defined Benefit Plans [Member] \| Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		35.00%
Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation		$ 412	398
Weighted-average assumed health care cost trend rate		7.40%
Ultimate weighted-average health care cost trend rate		7.00%
Ultimate weighted-average health care cost trend rate, anticipated achievement year		2016
Foreign Plans [Member] \| Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		39.00%
Foreign Plans [Member] \| Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		55.00%
Foreign Plans [Member] \| Cash and Other Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		4.00%
Foreign Plans [Member] \| Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of weighted-average target asset allocation		2.00%
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution		$ 3
Curtailments gain (loss)		7	1
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution		13
Curtailments gain (loss)		$ 2	$ 4

Employee Benefit Plans - Change in Benefit Obligations and Change in Plan Assets (Detail) - USD ($)
$ in Millions

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

$ (7)

Fair value of plan assets at beginning of year

$ (1)

505

Fair value of plan assets at end of year

530

505

U.S. Pension Benefits [Member]

195

147

Service cost

(19)

^[1]

^[2]

(11)

(7)

(1)

Fair value of plan assets at beginning of year

170

195

147

149

103

Actual return on plan assets

^[2]

(10)

(11)

Expenses paid from assets

(1)

Fair value of plan assets at end of year

155

149

103

(15)

(46)

Foreign Pension Benefits [Member]

(15)

(46)

422

236

Service cost

Plan participants' contribution

Foreign currency exchange rate changes

^[2]

(17)

(11)

(2)

(4)

140

Divestiture of CSM

(5)

Other

(1)

Fair value of plan assets at beginning of year

439

422

236

356

197

Actual return on plan assets

Plan participants' contribution

Foreign currency exchange rate changes

^[2]

(17)

(11)

Settlements

(1)

(5)

Divestiture of Supermetals Business

133

(3)

Expenses paid from assets

(1)

Fair value of plan assets at end of year

375

356

197

(64)

(66)

U. S. Postretirement Benefits [Member]

(64)

(66)

Service cost

(6)

^[2]

(5)

(1)

^[2]

(5)

(55)

(64)

Foreign Postretirement Benefits [Member]

(55)

(64)

Foreign currency exchange rate changes

(1)

^[2]

(1)

$ 15

^[2]

(1)

(17)

(18)

$ (17)

$ (18)

[1]

During fiscal 2013, the Company approved the freezing of a U.S. pension plan that resulted in the remeasurement of the plans assets and liabilities. The remeasurement decreased the net pension obligation of these plans, which is included within Other Liabilities caption on the Consolidated Balance Sheets, by $19 million and increased Accumulated other comprehensive income by $13 million, net of tax. The impact to the Company's Net periodic benefit cost was less than $1 million.

[2]

Included in this amount is $7 million that the Company paid directly to the participants in its defined benefit plans in both fiscal 2013 and 2012.

Employee Benefit Plans - Change in Benefit Obligations and Change in Plan Assets (Parenthetical) (Detail) - USD ($)
$ in Millions

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Increase decrease in pension obligation plans

$ 7

(11)

(38)

$ (12)

Accumulated other comprehensive income loss on pension plan, net of tax

(15)

$ 21

U.S. Pension Benefits [Member]

Increase decrease in pension obligation plans

^[1]

$ 11

(19)

Accumulated other comprehensive income loss on pension plan, net of tax

Maximum [Member]

Company's Net periodic benefit cost

$ 1

[1]	Included in this amount is $7 million that the Company paid directly to the participants in its defined benefit plans in both fiscal 2013 and 2012.

Employee Benefit Plans - Assumptions Used to Determine Pension Benefit Obligations (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.50%	3.50%	4.50%
Initial health care cost trend rate	3.00%	3.50%	3.80%
Discount rate	3.50%	4.50%	4.50%
Expected long-term rate of return on plan assets	7.80%	7.80%	7.80%
Initial health care cost trend rate	3.50%	3.80%	3.80%
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.80%	3.60%	4.80%
Initial health care cost trend rate	3.10%	3.10%	3.10%
Discount rate	3.60%	4.80%	4.30%
Expected long-term rate of return on plan assets	5.30%	5.30%	6.10%
Initial health care cost trend rate	3.10%	3.20%	3.30%
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	3.30%	4.50%
Initial health care cost trend rate	7.50%	8.00%	8.50%
Discount rate	3.30%	4.50%	4.50%
Initial health care cost trend rate	8.00%	8.50%	7.50%
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.40%	3.90%	4.90%
Initial health care cost trend rate	7.50%	7.40%	8.00%
Discount rate	3.90%	4.90%	4.80%
Initial health care cost trend rate	7.40%	7.90%	8.00%

Employee Benefit Plans - Net Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	$ (149)	$ (190)
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	(15)	(46)
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	4	4
Current liabilities	(1)	(1)
Noncurrent liabilities	(67)	(69)
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(5)	(6)
Noncurrent liabilities	(50)	(58)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current liabilities		(1)
Noncurrent liabilities	$ (17)	$ (17)

Employee Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	$ (4)	$ 29
Net prior service cost (credit)		1
Balance in accumulated other comprehensive income, pretax	(4)	30
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	78	77
Balance in accumulated other comprehensive income, pretax	78	77
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	(3)	3
Net prior service cost (credit)	(7)	(10)
Balance in accumulated other comprehensive income, pretax	(10)	(7)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	3	3
Balance in accumulated other comprehensive income, pretax	$ 3	$ 3

Employee Benefit Plans - Estimated Future Benefit Payments (Detail) $ in Millions	Sep. 30, 2013 USD ($)
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2014	$ 12
2015	11
2016	14
2017	13
2018	12
2019-2023	60
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2014	16
2015	17
2016	20
2017	19
2018	20
2019-2023	117
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2014	5
2015	5
2016	5
2017	5
2018	5
2019-2023	20
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2014	1
2015	1
2016	1
2017	1
2018	1
2019-2023	$ 5

Employee Benefit Plans - Net Periodic Defined Benefit Pension and Other Postretirement Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Settlements or curtailments cost (income)	$ (3)	$ (1)	$ 1
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5	5
Interest cost	6	7	6
Expected return on plan assets	(10)	(9)	(8)
Net losses	1	1
Settlements or curtailments cost (income)	7	1
Net periodic benefit cost	4	5	3
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	7	6
Interest cost	15	11	11
Expected return on plan assets	(18)	(13)	(13)
Net losses	4	3	3
Settlements or curtailments cost (income)	2	4
Other	2	(1)	2
Net periodic benefit cost	12	9	9
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	1
Interest cost	2	2	2
Amortization of prior service cost	(3)	(3)	(3)
Settlements or curtailments cost (income)		1
Net periodic benefit cost	(1)	(1)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	1
Net periodic benefit cost	$ 1	$ 1	$ 1

Employee Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, Pre-Tax (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (gains) losses	$ (32)	$ (3)	$ 2
Prior service cost		(1)
Amortization of prior unrecognized loss	(2)	(1)
Total other comprehensive (income) loss	(34)	(5)	2
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (gains) losses	8	27	1
Amortization of prior unrecognized loss	(4)	(3)	(3)
Other	(4)	1
Total other comprehensive (income) loss		25	(2)
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (gains) losses	(6)	1	(1)
Prior service cost	3	1	(2)
Amortization of prior service (cost) credit		3	4
Total other comprehensive (income) loss	$ (3)	5	1
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net (gains) losses		1	(1)
Total other comprehensive (income) loss		$ 1	$ (1)

Employee Benefit Plans - Sensitivity Analysis (Detail) - Foreign Postretirement Benefits [Member] $ in Millions	12 Months Ended
	Sep. 30, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items]
1 -Percent-Point Increase, Effect on postretirement benefit obligation	$ 3
1 -Percent-Point Decrease, Effect on postretirement benefit obligation	$ (2)

Employee Benefit Plans - Defined Benefit Pension Plans Weighted-Average Asset Allocations (Detail)	Sep. 30, 2013	Sep. 30, 2012
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities	63.00%	62.00%
Debt securities	37.00%	38.00%
Total	100.00%	100.00%
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities	41.00%	39.00%
Debt securities	54.00%	56.00%
Cash and other securities	5.00%	5.00%
Total	100.00%	100.00%

Employee Benefit Plans - Fair Value of Pension Plan Assets by Asset Category (Detail) - USD ($)
$ in Millions

Sep. 30, 2013

Sep. 30, 2012

Total Direct Investments [Member]

$ 530

$ 505

Total Investment Funds [Member]

Alternative Investments [Member]

442

404

Cash [Member]

U.S. Equity Securities [Member] | Total Direct Investments [Member]

Non-U.S. Equity Securities [Member] | Total Direct Investments [Member]

Non-U.S. Government Bonds [Member] | Total Direct Investments [Member]

Non-U.S. Corporate Bonds [Member] | Total Direct Investments [Member]

Equity Funds [Member] | Total Investment Funds [Member]

Fixed Income Funds [Member] | Total Investment Funds [Member]

^[1]

233

205

Real Estate Funds [Member] | Total Investment Funds [Member]

^[2]

204

192

Common and Collective Investment Trust Funds [Member] | Total Investment Funds [Member]

^[3]

Money Market Funds [Member] | Total Investment Funds [Member]

^[4]

Other Investments [Member] | Total Investment Funds [Member]

Insurance Contracts [Member] | Alternative Investments [Member]

Other [Member] | Alternative Investments [Member]

^[5]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Total Direct Investments [Member]

303

257

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Total Investment Funds [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]

228

168

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Equity Securities [Member] | Total Direct Investments [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Non-U.S. Equity Securities [Member] | Total Direct Investments [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Non-U.S. Government Bonds [Member] | Total Direct Investments [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Non-U.S. Corporate Bonds [Member] | Total Direct Investments [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Funds [Member] | Total Investment Funds [Member]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Funds [Member] | Total Investment Funds [Member]

^[1]

132

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money Market Funds [Member] | Total Investment Funds [Member]

^[2]

Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Investments [Member] | Total Investment Funds [Member]

Significant Observable Inputs (Level 2) [Member]

Significant Observable Inputs (Level 2) [Member] | Total Investment Funds [Member]

227

248

Significant Observable Inputs (Level 2) [Member] | Alternative Investments [Member]

214

236

Significant Observable Inputs (Level 2) [Member] | Cash [Member]

Significant Observable Inputs (Level 2) [Member] | Equity Funds [Member] | Total Investment Funds [Member]

Significant Observable Inputs (Level 2) [Member] | Fixed Income Funds [Member] | Total Investment Funds [Member]

^[1]

101

108

Significant Observable Inputs (Level 2) [Member] | Real Estate Funds [Member] | Total Investment Funds [Member]

^[2]

111

126

Significant Observable Inputs (Level 2) [Member] | Common and Collective Investment Trust Funds [Member] | Total Investment Funds [Member]

^[3]

Significant Observable Inputs (Level 2) [Member] | Insurance Contracts [Member] | Alternative Investments [Member]

^[4]

Significant Observable Inputs (Level 2) [Member] | Other [Member] | Alternative Investments [Member]

^[5]

$ 12

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

$ 1

[1]	The equity funds asset class includes funds that invest in U.S. equities as well as equity securities issued by companies incorporated, listed or domiciled in countries in developed and/or emerging markets. These companies may be in the small-, mid- or large-cap categories.
[2]	The fixed income funds asset class includes investments in high quality funds. High quality fixed income funds primarily invest in low risk U.S. and non-U.S. government securities, investment-grade corporate bonds, mortgages and asset-backed securities. A significant portion of the fixed income funds asset includes investment in long-term bond funds.
[3]	The real estate funds asset class includes funds that primarily invest in entities which are principally engaged in the ownership, acquisition, development, financing, sale and/or management of income-producing real estate properties, both commercial and residential. These funds typically seek long-term growth of capital and current income that is above average relative to public equity funds.
[4]	The investment objective of the portfolio of this common and collective investment trust is to achieve long-term, total return in excess of the MSCI World Index Benchmark by investing in equity securities of companies worldwide, emphasizing those with above-average potential for capital appreciation.
[5]	Insurance contracts held by the Company's non-U.S. plans are issued by well-known, highly rated insurance companies.

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2009	Mar. 08, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, authorized shares					8,900,000
Percentage of vesting in first anniversary	30.00%
Percentage of vesting in second anniversary	30.00%
Percentage of vesting in third anniversary	40.00%
Stock based compensation outstanding units	42,304
Cash settled awards	$ 1	$ 1
Net stock-based compensation expense	$ 8	10	$ 10
Closing common stock price	$ 42.71
Estimated weighted average grant date fair values of options granted	$ 12.46
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of exercise price equal to market price on the date of grant	100.00%
Vesting period (in years)	3 years
Expiration period, years	10 years			5 years
Intrinsic value of options exercised	$ 5	9	3
Cash received from exercises	$ 5	$ 9	$ 4
Estimated weighted average grant date fair values of options granted	$ 12.46	$ 11.64	$ 12.09
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Percentage of market price	30.00%
Intrinsic value of restricted stock units vested			$ 27
Awards granted	0	0	0
Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of restricted stock units vested	$ 1	$ 1
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Estimated weighted average grant date fair value	$ 35.28	$ 33.15	$ 34.76
Intrinsic value of restricted stock units vested	$ 16	$ 1
Restricted Stock Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of restricted stock units vested			$ 1
Unvested Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested	$ 10
Weighted-average period, years	1 year 2 months 12 days
Unvested Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested	$ 3
Weighted-average period, years	10 months 24 days
Unvested Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period, years	4 months 24 days
Unvested Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested	$ 1
Supplemental Retirement Savings Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Supplemental retirement savings plan, aggregate value of the accounts, shares	133,000	110,000
Supplemental retirement savings plan aggregate value of the accounts paid in cash	$ 1	$ 1

Stock-Based Compensation - Stock-Based Compensation Expenses (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before tax	$ 12	$ 15	$ 15
Income tax benefit	(4)	(5)	(5)
Net stock-based compensation expense	8	10	10
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before tax	4	5	5
Selling and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before tax	7	9	9
Research and Technical Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before tax	$ 1	$ 1	$ 1

Stock-Based Compensation - Equity Incentive Plan Activity (Detail)

12 Months Ended

Sep. 30, 2013

$ / shares

Stock Options, Total Options, Outstanding at September 30, 2012 | shares

1,579,000

Stock Options, Total Options, Granted | shares

301,000

Stock Options, Total Options, Performance-based adjustment | shares

^[1]

Stock Options, Total Options, Exercised / Vested | shares

(245,000)

^[2]

Stock Options, Total Options, Cancelled / Forfeited | shares

(12,000)

Stock Options, Total Options, Outstanding at September 30, 2013 | shares

1,623,000

Stock Options, Total Options, Exercisable at September 30, 2013 | shares

1,029,000

Exercisable and expected to vest | shares

1,611,000

^[3]

Stock Options, Weighted Average Exercise Price, Outstanding at September 30, 2012

$ 24.17

Stock Options, Weighted Average Exercise Price, Granted

35.25

Stock Options, Weighted Average Exercise Price, Performance-based adjustment

^[1]

Stock Options, Weighted Average Exercise Price, Exercised / Vested

19.10

^[2]

Stock Options, Weighted Average Exercise Price, Cancelled / Forfeited

32.04

Stock Options, Weighted Average Exercise Price, Outstanding at September 30, 2013

26.93

Exercisable at September 30, 2013

22.63

Exercisable and expected to vest

26.87

^[3]

Stock Options, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2012

7.37

Stock Options, Weighted Average Grant Date Fair Value, Granted

12.46

Stock Options, Weighted Average Grant Date Fair Value, Performance-based adjustment

^[1]

Stock Options, Weighted Average Grant Date Fair Value, Exercised / Vested

4.77

^[2]

Stock Options, Weighted Average Grant Date Fair Value, Cancelled / Forfeited

7.30

Stock Options, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2013

$ 8.71

Restricted Stock / Units, Outstanding at September 30, 2013 | shares

42,304

Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted Stock / Units, Outstanding at September 30, 2012 | shares

2,000

Restricted Stock / Units, Exercised / Vested | shares

(1,000)

^[2]

Restricted Stock / Units, Outstanding at September 30, 2013 | shares

1,000

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2012

$ 9.56

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Exercised / Vested

9.56

^[2]

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2013

$ 9.56

Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted Stock / Units, Outstanding at September 30, 2012 | shares

1,231,000

^[4]

Restricted Stock / Units, Granted | shares

417,000

^[4]

Restricted Stock / Units, Performance-based adjustment | shares

(142,000)

^[1],[4]

Restricted Stock / Units, Exercised / Vested | shares

(440,000)

^[2],[4]

Restricted Stock / Units, Cancelled / Forfeited | shares

(27,000)

^[4]

Restricted Stock / Units, Outstanding at September 30, 2013 | shares

1,039,000

^[4]

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2012

$ 30.28

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Granted

$ 35.28

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Performance-based adjustment | shares

34.43

^[1]

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Exercised / Vested

$ 23.84

^[2]

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Cancelled / Forfeited

32.43

Restricted Stock / Units, Weighted Average Grant Date Fair Value, Outstanding at September 30, 2013

$ 34.39

[1]	Represents the incremental number of shares cancelled upon vesting of outstanding performance-based restricted stock units, based on the Company achieving performance at a level less than target under the 2013 performance targets.
[2]	"Exercised / Vested" includes 160,740 Restricted Stock Units and 379 shares of restricted stock that vested during the year ended September 30, 2013 but were withheld at the request of the award recipient to cover withholding taxes associated with the vesting. The units were added back to the shares available for future issuance under our 2009 Long-Term Incentive Plan.
[3]	Stock options exercisable and expected to vest in the future, net of estimated forfeitures.
[4]	The number "Granted" represents the number of shares issuable upon vesting of time-based restricted stock units and performance-based restricted stock units, assuming the Company performs at the target performance level in each year of the three-year performance per

Stock-Based Compensation - Equity Incentive Plan Activity (Parenthetical) (Detail)	Sep. 30, 2013 shares
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested during the period	160,740
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares vested during the period	379

Stock-Based Compensation - Stock Options Outstanding and Vested Options (Detail) $ in Millions	12 Months Ended
	Sep. 30, 2013 USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Total Options Outstanding, Aggregate Intrinsic Value	$ 26
Total Options Outstanding, Weighted Average Remaining Contractual Term (in years)	7 years
Exercisable Options, Aggregate Intrinsic Value	$ 21
Exercisable Options, Weighted Average Remaining Contractual Term (in years)	6 years 2 months 12 days
Exercisable and Expected to Vest, Aggregate Intrinsic Value	$ 26
Exercisable and Expected to Vest, Weighted Average Remaining Contractual Term (in years)	7 years

Stock-Based Compensation - Weighted-Average Assumptions (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected stock price volatility	46.00%	45.00%	43.00%
Risk free interest rate	0.90%	1.30%	1.80%
Expected life of options (years)	6 years	6 years	6 years
Expected annual dividends per year	$ 0.80	$ 0.72	$ 0.72

Restructuring - Recorded Restructuring Activities (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, period expense	$ 37	$ 15	$ 18
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, period expense	28	13	16
Selling and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, period expense	7	$ 2	$ 2
Research and Technical Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, period expense	$ 2

Restructuring - Restructuring Activities and Related Reserves (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Restructuring Cost and Reserve [Line Items]
Reserve balance	$ 5	$ 11
Charges	37	15	$ 18
Costs charged against assets	(21)	(10)
Proceeds from sale		4
Cash paid	(11)	(14)
Foreign currency translation adjustment		(1)
Reserve balance	10	5	11
Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	2	9
Charges	13	3
Cash paid	(8)	(10)
Reserve balance	7	2	9
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	1
Charges	1	3
Cash paid		(2)
Reserve balance	2	1
Asset Impairment and Accelerated Depreciation [Member]
Restructuring Cost and Reserve [Line Items]
Charges	19	7
Costs charged against assets	(19)	(7)
Asset Sales [Member]
Restructuring Cost and Reserve [Line Items]
Charges		(1)
Costs charged against assets		(3)
Proceeds from sale		4
Other [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	2	2
Charges	4	3
Costs charged against assets	(2)
Cash paid	(3)	(2)
Foreign currency translation adjustment		(1)
Reserve balance	$ 1	$ 2	$ 2

Restructuring - Additional Information (Detail) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2012 Employees	Sep. 30, 2013 USD ($) Employees	Sep. 30, 2012 USD ($)	Sep. 30, 2011 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 37	$ 15	$ 18
Cash payments		11	14
Restructuring costs in accrued expenses		10	5	11
Previous Actions and Sites Pending Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		2	8	13
Restructuring accelerated depreciation and asset impairments		60	2	3
Severance charges		65
Site demolition, clearing and environmental remediation costs		11	3	3
Pre-tax charge to earnings		154
Cash payments		82
Restructuring costs in accrued expenses		4
Other charges		19
Additional charges during fiscal 2014 and thereafter		4
Gain on sale of assets		$ 1
Gain on sale of assets			1
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Equity share in CMSB		50.00%
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1	3
Cash payments			2
Restructuring costs in accrued expenses		2	1
Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		13	3
Cash payments		8	10
Restructuring costs in accrued expenses		$ 7	2	9
Severance and Employee Benefits [Member] \| Previous Actions and Sites Pending Sale [Member]
Restructuring Cost and Reserve [Line Items]
Severance charges			1	3
Other Post Closing Costs [Member] \| Previous Actions and Sites Pending Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			3	4
Closure of Port Dickson [Member]
Restructuring Cost and Reserve [Line Items]
Equity share in CMSB		51.00%
Affected employees \| Employees		90
Restructuring charges		$ 18
Restructuring accelerated depreciation and asset impairments		16
Severance charges		2
Site demolition, clearing and environmental remediation costs		$ 6
Portion of the charges that are allocable to the noncontrolling interest		49.00%
Pre-tax charge to earnings		$ 24
Expected cumulative net cash outlays related to plan		8
Expected cash outlays beyond fiscal year		6
Restructuring costs in accrued expenses		1
Closure of Port Dickson [Member] \| Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Expected cumulative net cash outlays related to plan		6
Closure of Port Dickson [Member] \| Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Expected cumulative net cash outlays related to plan		2
Closure of Port Dickson [Member] \| Severance Costs [Member]
Restructuring Cost and Reserve [Line Items]
Pre-tax charge to earnings		1
Cash payments		1
Closure of Hong Kong [Member]
Restructuring Cost and Reserve [Line Items]
Affected employees \| Employees	64
Restructuring charges		1	6
Cash payments		2
Closure of Hong Kong [Member] \| Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected cash outlays remainder fiscal year		1
Accrued severance charges		1
Restructuring Activities Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		15	$ 1	$ 5
Severance charges		10
Accelerated depreciation and asset write-offs		3
Other charges		2
Additional charges during fiscal 2014 and thereafter		7
Restructuring Activities Other [Member] \| Severance Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cash payments		11
Expected cash outlays remainder fiscal year		8
Accrued severance charges		$ 5

Earnings Per Share - Components of Basic and Diluted Earnings Per Common Share (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Basic EPS:

Less: Dividends and dividend equivalents to participating securities

$ 47

$ 59

$ 27

$ 20

$ 36

$ 66

$ 240

$ 46

$ 153

$ 388

$ 236

Less: Undistributed earnings allocated to participating securities

^[1]

Earnings allocated to common shareholders (numerator)

$ 152

$ 385

$ 233

Weighted average common shares and participating securities outstanding

64.4

64.0

65.4

Less: Participating securities

^[1]

0.6

0.8

Adjusted weighted average common shares (denominator)

63.8

63.4

64.6

Income from continuing operations attributable to Cabot Corporation

$ 0.72

$ 0.86

$ 0.43

$ 0.33

$ 0.55

$ 0.97

$ 0.80

$ 0.55

$ 2.34

$ 2.87

$ 2.80

0.02

0.04

(0.02)

0.02

0.07

2.94

0.17

0.04

3.20

0.82

Earnings allocated to common shareholders

0.74

0.90

0.43

0.31

0.57

1.04

3.74

0.72

$ 2.38

$ 6.07

$ 3.62

Diluted EPS:

$ 152

$ 385

$ 233

Plus: Earnings allocated to participating securities

Less: Adjusted earnings allocated to participating securities

^[2]

(1)

(3)

Earnings available to common shares (numerator)

$ 152

$ 385

$ 233

Adjusted weighted average common shares outstanding

63.8

63.4

64.6

Common shares issuable

^[3]

0.7

0.8

Adjusted weighted average common shares (denominator)

64.5

64.2

65.4

Income from continuing operations attributable to Cabot Corporation

0.71

0.86

0.42

0.33

0.54

0.96

0.78

0.55

$ 2.32

$ 2.83

$ 2.77

0.02

0.04

(0.02)

0.02

0.06

2.92

0.16

0.04

3.16

0.80

$ 0.73

$ 0.90

$ 0.42

$ 0.31

$ 0.56

$ 1.02

$ 3.70

$ 0.71

$ 2.36

$ 5.99

$ 3.57

[1]	Participating securities consist of shares of unvested restricted stock, vested restricted stock awards held by employees in which Cabot has a security interest, and unvested time-based restricted stock units.
[2]	Undistributed earnings are adjusted for the assumed distribution of dividends to the dilutive securities, which are described in (3) below, and then reallocated to participating securities.
[3]	Represents incremental shares of common stock from the (i) assumed exercise of stock options issued under Cabot's equity incentive plans; (ii) assumed issuance of shares to employees pursuant to the Company's Supplemental Retirement Savings Plan; and (iii) assumed issuance of shares for outstanding and achieved performance-based stock unit awards issued under Cabot's equity incentive plans using the treasury stock method. For fiscal 2013, 2012 and 2011, 301,328, 395,532 and 253,000 incremental shares of common stock were not included in the calculation of diluted earnings per share because the inclusion of these shares would have been antidilutive.

Earnings Per Share - Calculation of Undistributed Earnings (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Net income attributable to Cabot Corporation	$ 47	$ 59	$ 27	$ 20	$ 36	$ 66	$ 240	$ 46	$ 153	$ 388	$ 236
Less: Dividends declared on common stock									51	49	46
Less: Dividends and dividend equivalents to participating securities											1
Undistributed earnings									102	339	189
Undistributed earnings allocated to common shareholders									101	336	187
Undistributed earnings allocated to participating securities									$ 1	$ 3	$ 2

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Net Income
-URI http://asc.fasb.org/extlink&oid=6518256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.19)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.18)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.22)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=6519514

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e565-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 20
-Article 9

Income from continuing operations before income taxes and equity in earnings of affiliated companies

Earnings Per Share - Calculation of Undistributed Earnings (Parenthetical) (Detail) - shares	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Incremental shares of common stock	301,328	395,532	253,000

Income Taxes - Income (Loss) Before Income Taxes (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Income Tax Disclosure [Abstract]

Domestic

$ 35

$ 13

$ (25)

Foreign

170

232

228

$ 55

$ 73

$ 36

$ 41

$ 36

$ 78

$ 76

$ 55

$ 205

^[1]

$ 245

^[1]

$ 203

^[1]

[1]	Income (loss) from continuing operations before taxes for Unallocated and Other includes:

Income Taxes - Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Millions	3 Months Ended							12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
U.S. federal and state, Current								$ (3)	$ (1)	$ (7)
U.S. federal and state, Deferred								(8)	(8)	(51)
U.S. federal and state, Total								(11)	(9)	(58)
Foreign, Current								70	62	57
Foreign, Deferred								(1)	2	7
Foreign, Total								69	64	64
Total U.S and foreign	$ 7	$ 16	$ 16	$ 19	$ 16	$ 23	$ 16	$ 58	$ 55	$ 6

Income Taxes - Reconciliation using U.S. Statutory Rate (Detail) - USD ($) $ in Millions	3 Months Ended							12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Computed tax expense at the federal statutory rate								$ 72	$ 86	$ 70
Impact of taxation at different rates, repatriation and other								(27)	(29)	(29)
Impact of credit for extraordinary repatriation										(24)
Impact of investment incentive credits								(1)		(2)
Impact of foreign losses for which a current tax benefit is not available								9	5	6
Impact of non-deductible net currency losses								18
U.S. and state benefits from research and experimentation activities								(4)	(2)	(3)
Tax audit settlements								(6)	(2)	(12)
Reversal of state tax valuation allowance									(8)
Permanent and other differences								(4)	5
State taxes, net of federal effect								1
Total U.S and foreign	$ 7	$ 16	$ 16	$ 19	$ 16	$ 23	$ 16	$ 58	$ 55	$ 6

Income Taxes - Components of Deferred Income Taxes (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Deferred expenses	$ 29	$ 13
Other	28	36
Pension and other benefits	71	84
Net operating loss carry-forwards	187	194
Foreign tax credit carry-forwards	49	12
R&D credit carry-forwards	28	27
Other business credit carry-forwards	32	31
Subtotal	424	397
Valuation allowances	(166)	(169)
Total deferred tax assets	258	228
Intangible assets	(28)	(10)
Inventory		(2)
Property, plant and equipment	(149)	(141)
Unremitted earnings of non-U.S. subsidiaries		(11)
Total deferred tax liabilities	$ (177)	$ (164)

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended			36 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2013	Sep. 30, 2010
Income Taxes [Line Items]
Net tax charges related to tax settlements	$ 3	$ 1	$ 7
Foreign currency charge related to tax settlements	13
Offset of net tax benefit related to tax settlements	10
Net tax settlements and investment incentive tax credits		11	38
Tax benefits from repatriation of high taxed income		8	24
Tax settlements		3	14
Net operating loss carryforwards	807			$ 807
Other tax credit carryforwards	108			108
Undistributed earnings	1,180			1,180
Net deferred tax assets	81			81
Tax credits	70			243
Required future taxable operating income	$ 180
Expected term to realize deferred tax asset, years	20 years
Increased/(decreased) valuation allowance	$ (3)	31	12
Unrecognized tax benefits	50	55	65	50	$ 75
Unrecognized tax benefits, recorded	34			34
Unrecognized tax benefits, not recorded	16			16
Accruals for penalties	2	3		2
Accruals for interest	14	15		14
Favorable impact on tax provision	39
Total penalties and interest	3	$ 3	$ 3
U.S. Management [Member]
Income Taxes [Line Items]
Net deferred tax assets	$ 63			$ 63
U.S. federal [Member] \| Minimum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2007
U.S. federal [Member] \| Maximum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2012
State Jurisdiction [Member] \| Minimum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2004
State Jurisdiction [Member] \| Maximum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2012
Non-US [Member] \| Minimum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2001
Non-US [Member] \| Maximum [Member]
Income Taxes [Line Items]
Years remains subject to examination	2012

Income Taxes - Expiration Dates of Carryforwards (Detail) $ in Millions	Sep. 30, 2013 USD ($)
Significant Tax Attributes And Dates Of Expiration [Line Items]
NOLs	$ 807
Credits	108
2014 to 2020 [Member]
Significant Tax Attributes And Dates Of Expiration [Line Items]
NOLs	391
Credits	18
2021 and Thereafter [Member]
Significant Tax Attributes And Dates Of Expiration [Line Items]
NOLs	83
Credits	70
Indefinite Carry-Forwards [Member]
Significant Tax Attributes And Dates Of Expiration [Line Items]
NOLs	333
Credits	$ 20

Income Taxes - Expiration Dates of Carryforwards (Parenthetical) (Detail)	12 Months Ended
	Sep. 30, 2013
Significant Tax Attributes And Dates Of Expiration [Line Items]
Expiration periods	2021
Minimum [Member]
Significant Tax Attributes And Dates Of Expiration [Line Items]
Expiration periods	2014
Maximum [Member]
Significant Tax Attributes And Dates Of Expiration [Line Items]
Expiration periods	2020

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Balance at beginning of the year	$ 55	$ 65	$ 75
Additions based on tax provisions related to the current year	1	4	2
Additions for tax positions of prior years	2		1
Reductions for tax provisions of prior years	(5)	(10)	(2)
Reductions related to settlements			(4)
Reductions from lapse of statute of limitations	(3)	(4)	(7)
Balance at end of the year	$ 50	$ 55	$ 65

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Nov. 30, 2013 USD ($) Community	Sep. 30, 2013 USD ($) claimants	Sep. 30, 2012 USD ($) claimants	Sep. 30, 2011 USD ($)
Loss Contingencies [Line Items]
Lease expiration period, years		10 years
Rent expense under such operating lease agreement		$ 23,000,000	$ 15,000,000	$ 19,000,000
Aggregate self-insured liability		6,000,000
Retention for medical costs per person per annum		225,000
Interest expense		62,000,000	46,000,000	39,000,000
Non-Controlling Interests [Member]
Loss Contingencies [Line Items]
Raw materials purchases		150,000,000	116,000,000	134,000,000
Accounts payable and accrued liabilities		11,000,000	$ 13,000,000
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Annual fees paid by transferee to transferor company		$ 400,000
Number of claimants \| claimants		42,000	42,000
Respirator reserve on discounted basis		$ 11,000,000
Respirator reserve on undiscounted basis		15,000,000
Cash payments for respirator reserves		$ 2,000,000	$ 2,000,000	5,000,000
Discount rate		5.00%
Expected aggregate undiscounted amount of future payments, fiscal 2014		$ 2,000,000
Expected aggregate undiscounted amount of future payments, fiscal 2015		2,000,000
Expected aggregate undiscounted amount of future payments, fiscal 2016		1,000,000
Expected aggregate undiscounted amount of future payments, fiscal 2017		1,000,000
Expected aggregate undiscounted amount of future payments, fiscal 2018		1,000,000
Expected aggregate undiscounted amount of future payments, fiscal 2019 through 2065		8,000,000
Respirator Liabilities [Member] \| Maximum [Member]
Loss Contingencies [Line Items]
Interest expense		1,000,000
Environmental Matters [Member]
Loss Contingencies [Line Items]
Reserve for environmental matters		5,000,000	7,000,000
Reserve for environmental matters included in accrued expenses		2,000,000	3,000,000
Reserve for environmental matters included in other liabilities		3,000,000	4,000,000
Charges for environmental expense			3,000,000	1,000,000
Cash payments for environmental reserves		$ 2,000,000	2,000,000	2,000,000
Weighted average risk free rate for environmental liability		3.00%
Environmental Matters [Member] \| Operating and Maintenance Component [Member]
Loss Contingencies [Line Items]
Reserve for environmental matters		$ 3,000,000
Expected future payments, 2014		2,000,000
Environmental Matters [Member] \| Subsequent Event [Member]
Loss Contingencies [Line Items]
Civil penalty paid by cabot to EPA and LDEQ	$ 975,000
Amount of fund paid by Cabot in environmental mitigation projects	450,000
Expected capital cost to install controls	$ 85,000,000
Number of communities funded under environmental mitigation projects \| Community	3
Period for which estimated capital cost incurred	6 years 6 months
Environmental Matters [Member] \| Maximum [Member]
Loss Contingencies [Line Items]
Charges for environmental expense		1,000,000
Interest expense		1,000,000	$ 1,000,000	$ 1,000,000
Environmental Matters [Member] \| Maximum [Member] \| Operating and Maintenance Component [Member]
Loss Contingencies [Line Items]
Expected future payments, 2015		1,000,000
Expected future payments, 2016		1,000,000
Expected future payments, 2017		1,000,000
Expected future payments, 2018		1,000,000
Expected future payments, thereafter		$ 1,000,000

Commitments and Contingencies - Schedule of Future Minimum Rental Commitments under Non-Cancelable Leases (Detail) $ in Millions	Sep. 30, 2013 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2014	$ 22
2015	18
2016	14
2017	9
2018	8
2019 and thereafter	29
Total future minimum rental commitments	$ 100

Commitments and Contingencies - Schedule of Raw Material Purchased under Long Term Purchase Agreements (Detail) - USD ($)
$ in Millions

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

Reinforcement Materials [Member]

$ 441

$ 370

$ 358

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

371

312

340

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

Purification Solutions [Member]

$ 18

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

Advanced Technologies [Member]

^[1]

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

Raw Material Purchased Under Long Term Purchase Agreements [Line Items]

Other [Member]

$ 2

$ 1

[1]	The year ended September 30, 2012 includes two months of purchases for Norit.

Commitments and Contingencies - Schedule of Components of Purchase Commitments (Detail) $ in Millions	Sep. 30, 2013 USD ($)
Long-term Purchase Commitment [Line Items]
Payments Due by Fiscal Year 2014	$ 398
Payments Due by Fiscal Year 2015	347
Payments Due by Fiscal Year 2016	270
Payments Due by Fiscal Year 2017	219
Payments Due by Fiscal Year 2018	213
Payments Due Thereafter	3,037
Payments Due, Total	4,484
Reinforcement Materials [Member]
Long-term Purchase Commitment [Line Items]
Payments Due by Fiscal Year 2014	326
Payments Due by Fiscal Year 2015	293
Payments Due by Fiscal Year 2016	226
Payments Due by Fiscal Year 2017	183
Payments Due by Fiscal Year 2018	178
Payments Due Thereafter	2,793
Payments Due, Total	3,999
Performance Materials [Member]
Long-term Purchase Commitment [Line Items]
Payments Due by Fiscal Year 2014	42
Payments Due by Fiscal Year 2015	37
Payments Due by Fiscal Year 2016	33
Payments Due by Fiscal Year 2017	25
Payments Due by Fiscal Year 2018	25
Payments Due Thereafter	226
Payments Due, Total	388
Purification Solutions [Member]
Long-term Purchase Commitment [Line Items]
Payments Due by Fiscal Year 2014	28
Payments Due by Fiscal Year 2015	15
Payments Due by Fiscal Year 2016	10
Payments Due by Fiscal Year 2017	10
Payments Due by Fiscal Year 2018	9
Payments Due Thereafter	17
Payments Due, Total	89
Advanced Technologies [Member]
Long-term Purchase Commitment [Line Items]
Payments Due by Fiscal Year 2014	2
Payments Due by Fiscal Year 2015	2
Payments Due by Fiscal Year 2016	1
Payments Due by Fiscal Year 2017	1
Payments Due by Fiscal Year 2018	1
Payments Due Thereafter	1
Payments Due, Total	$ 8

Concentration of Credit Risk - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Concentration Risk [Line Items]
Notes receivable from sale of business	$ 214	$ 252
No Customer of Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration of risk percentage	10.00%	10.00%	10.00%

Concentration of Credit Risk - Schedule of Account Receivable (Detail) - USD ($) $ in Millions	Sep. 30, 2013	Sep. 30, 2012
Tire Manufacturers [Member]
Concentration Risk [Line Items]
Accounts receivable	$ 298	$ 346

Financial Information by Segment & Geographic Area - Additional Information (Detail)
$ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

USD ($)

Jun. 30, 2013

USD ($)

Mar. 31, 2013

USD ($)

Dec. 31, 2012

USD ($)

Sep. 30, 2012

USD ($)

Jun. 30, 2012

USD ($)

Mar. 31, 2012

USD ($)

Dec. 31, 2011

USD ($)

Sep. 30, 2013

USD ($)

Segment

Business_Unit

Sep. 30, 2012

USD ($)

Sep. 30, 2011

USD ($)

Number of reportable segment | Segment

Number of operating segments | Segment

Income form continuing operations

$ 158

$ 201

$ 205

Total assets

^[1]

$ 4,233

$ 4,399

4,233

4,399

3,141

Capital expenditure

Equity earnings of affiliated companies

190

154

142

$ 3

$ 4

$ 3

$ 1

Specialty Fluids [Member]

Income form continuing operations

Total assets

$ 110

$ 111

110

111

101

Capital expenditure

Equity earnings of affiliated companies

$ 0

Number of business activity | Business_Unit

[1]	Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters' assets, and current and non-current assets held for sale.

Financial Information by Segments & Geographic Area - Schedule of Performance Segment (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Net sales	$ 898	$ 903	$ 842	$ 820	$ 848	$ 846	$ 844	$ 762	$ 3,463	$ 3,300
Performance Materials [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									904	914	$ 880
Performance Materials [Member] \| Specialty Carbons and Compounds [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									622	664	626
Performance Materials [Member] \| Fumed Metal Oxides [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									$ 282	$ 250	$ 254

Financial Information by Segments & Geographic Area - Schedule of Advanced Technologies Business Segment (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Net sales	$ 898	$ 903	$ 842	$ 820	$ 848	$ 846	$ 844	$ 762	$ 3,463	$ 3,300
Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									222	210	$ 186
Inkjet Colorants [Member] \| Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									64	66	65
Aerogel [Member] \| Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									21	18	24
Security Materials [Member] \| Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									7	9	11
Elastomer Composites [Member] \| Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									29	23	17
Specialty Fluids [Member] \| Operating Segments [Member] \| Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Net sales									$ 101	$ 94	$ 69

Financial Information by Segments & Geographic Area - Financial Information by Reportable Segment (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

^[1]

$ 3,463

$ 3,300

$ 3,102

190

156

139

Income from continuing operations before income taxes and equity in earnings of affiliated companies

$ 2

$ 3

$ 4

$ 3

$ 1

$ 73

$ 36

$ 41

$ 78

$ 76

$ 55

205

^[2]

245

^[2]

203

^[2]

Total expenditures for additions to long-lived assets

^[3]

4,233

4,399

4,233

4,399

3,141

^[4]

264

622

241

Unallocated and Other [Member]

^{[1],[2],[5],[6]}

^[2],[5],[6]

(4)

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2],[5],[6]

(4)

^[2],[5],[6]

(179)

(164)

(151)

Total expenditures for additions to long-lived assets

^{[2],[3],[5],[6]}

447

513

447

513

780

^{[2],[4],[5],[6]}

Reinforcement Materials [Member] | Operating Segments [Member]

^[1]

1,902

2,019

1,952

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2]

188

227

183

Total expenditures for additions to long-lived assets

^[3]

1,512

1,527

1,512

1,527

1,509

^[4]

172

163

126

Performance Materials [Member] | Operating Segments [Member]

^[1]

904

914

880

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2]

132

128

140

Total expenditures for additions to long-lived assets

^[3]

688

717

688

717

661

^[4]

Advanced Technologies [Member] | Operating Segments [Member]

^[1]

222

210

186

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2]

Total expenditures for additions to long-lived assets

^[3]

198

209

198

209

191

^[4]

Purification Solutions [Member] | Operating Segments [Member]

^[1]

348

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2]

(4)

Total expenditures for additions to long-lived assets

^[3]

1,388

1,433

1,388

1,433

^[4]

350

Segment Total [Member] | Operating Segments [Member]

^[1]

3,376

3,204

3,018

194

150

131

Income from continuing operations before income taxes and equity in earnings of affiliated companies

^[2]

384

409

354

Total expenditures for additions to long-lived assets

^[3]

$ 3,786

$ 3,886

3,786

3,886

2,361

^[4]

$ 261

$ 616

$ 235

[1]	Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, the impact of the corporate adjustment for unearned revenue and Notes receivable.
[2]	Income (loss) from continuing operations before taxes for Unallocated and Other includes:
[3]	Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters' assets, and current and non-current assets held for sale.
[4]	Expenditures for additions to long-lived assets include total equity and other investments (including available-for-sale securities) and property, plant and equipment.
[5]	Included in this amount is $7 million that the Company paid directly to the participants in its defined benefit plans in both fiscal 2013 and 2012.
[6]	Unallocated and other includes certain items and eliminations necessary to reflect management's reporting of operating segment results. These items are reflective of the segment reporting presented to the Chief Operating Decision Maker.

Financial Information by Segments & Geographic Area - Royalties Paid by Equity Affiliates, External Shipping and Handling Fees, Impact of Corporate Adjustment for Unearned Revenue and Notes Receivable Reflected by Unallocated and Other (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Net sales	$ 898	$ 903	$ 842	$ 820	$ 848	$ 846	$ 844	$ 762	$ 3,463	$ 3,300
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales									87	96	$ 84
Unallocated and Other [Member] \| Other Products and Services [Member]
Segment Reporting Information [Line Items]
Net sales									5	11	(2)
Unallocated and Other [Member] \| Shipping and Handling Fees [Member]
Segment Reporting Information [Line Items]
Net sales									$ 82	$ 85	$ 86

Financial Information by Segment & Geographic Area - Schedule of Income (Loss) Before Taxes for Unallocated and Other (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Equity in earnings of affiliated companies, net of tax

Interest expense

$ (62)

$ (46)

$ (39)

$ 2

$ 3

$ 4

$ 3

$ 1

Income from continuing operations before income taxes and equity in earnings of affiliated companies

$ 55

$ 73

$ 36

$ 41

$ 36

$ 78

$ 76

$ 55

205

^[1]

245

^[1]

203

^[1]

Unallocated and Other [Member]

Total certain items, pre-tax

Interest expense

(62)

(46)

(39)

^[2]

(56)

(51)

(19)

Equity in earnings of affiliated companies, net of tax

^[3]

(11)

(8)

Unallocated corporate costs

^[4]

(49)

(56)

(53)

General unallocated expense

^[5]

(1)

(32)

Income from continuing operations before income taxes and equity in earnings of affiliated companies

$ (179)

$ (164)

$ (151)

[1]	Income (loss) from continuing operations before taxes for Unallocated and Other includes:
[2]	Certain items are items that management does not consider to be representative of operating segment results and they are, therefore, excluded from Segment EBIT. Certain items, pre-tax, for fiscal 2013 primarily include $37 million related to global restructuring activities, $21 million for acquisition related charges (consisting of $10 million for certain other one-time integration costs and $11 million of additional charges related to acquisition accounting adjustments for the acquired inventory) and $1 million for environmental reserves offset by $3 million of certain foreign currency gains recorded by foreign subsidiaries. Certain items, pre-tax, for fiscal 2012 primarily include $17 million related to global restructuring activities, $26 million for acquisition related charges (consisting of $14 million of legal and professional fees, $3 million for certain other one-time integration costs and $9 million of additional charges related to acquisition accounting adjustments for the acquired inventory), $4 million for environmental and legal reserves, and a $4 million addition in the reserve for respirator claims. Certain items, pre-tax, for fiscal 2011 primarily include charges for global restructuring activities discussed in Note O.
[3]	Equity in earnings of affiliated companies, net of tax, is included in Segment EBIT and is removed from Unallocated and other to reconcile to income (loss) from operations before taxes.
[4]	Unallocated corporate costs are not controlled by the segments and primarily benefit corporate interests.
[5]	General unallocated expense consists of gains (losses) arising from foreign currency transactions, net of other foreign currency risk management activities, the impact of accounting for certain inventory on a LIFO basis, the profit or loss related to the corporate adjustment for unearned revenue, and the impact of including the full operating results of an equity affiliate in Purification Solutions segment EBIT. Additionally, for fiscal 2011, this amount included a $3 million charge related to a change in the net worth tax regulations in Colombia, and $3 million related to a portion of the benefit from a legal judgment.

Financial Information by Segment & Geographic Area - Schedule of Income (Loss) Before Taxes for Unallocated and Other (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Restructuring charges	$ 37	$ 15	$ 18
Benefit from a legal judgment			3
Certain Items [Member]
Segment Reporting Information [Line Items]
Acquisition related charges	37	26
Restructuring charges	21	17
Environmental reserves and legal settlements		14
Foreign currency exchange rate, re measurement income (loss)	3
Reserve for environmental matters	1
One-time integration costs	10	3
Acquisition of accounting adjustments for acquired inventory	$ 11	9
Certain Items [Member] \| 2009 Global Restructuring Plan [Member]
Segment Reporting Information [Line Items]
Environmental reserves and legal settlements		4
Reserve for respirator claim		$ 4
Colombia [Member]
Segment Reporting Information [Line Items]
Charge related to change in net worth tax regulations			$ 3

Financial Information by Segment & Geographic Area - Revenues from External Customers and Long-Lived Asset Information by Geographic Area (Detail) - USD ($)
$ in Millions

12 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

^[1]

$ 3,463

$ 3,300

$ 3,102

1,605

1,552

1,036

US [Member]

825

695

589

493

486

233

China [Member]

558

543

554

385

305

274

Netherlands [Member]

224

131

115

Other Foreign Countries [Member]

211

208

1,856

1,931

1,844

Quarterly Financial Information Disclosure [Abstract]

$ 516

$ 553

$ 484

[1]	Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, the impact of the corporate adjustment for unearned revenue and Notes receivable.

Unaudited Quarterly Financial Information - Schedule of Quarterly Financial Information (Detail) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

Net sales and other operating revenues

$ 898

$ 903

$ 842

$ 820

$ 848

$ 846

$ 844

$ 762

$ 3,463

$ 3,300

Gross profit

168

177

144

147

157

175

173

143

636

648

$ 558

Selling and administrative expenses

299

285

249

Research and technical expenses

Income from operations

263

290

243

Net interest expense and other charges

(18)

(13)

(14)

(16)

(12)

(11)

(6)

(58)

(45)

Income from continuing operations before income taxes and equity in earnings of affiliated companies

205

^[1]

245

^[1]

203

^[1]

Provision for income taxes

(7)

(16)

(19)

(16)

(23)

(16)

(58)

(55)

(6)

Income from discontinued operations, net of tax

(1)

189

205

Net income

245

160

406

258

Net income attributable to noncontrolling interests, net of tax

(4)

Income from continuing operations

$ 47

$ 59

$ 27

$ 20

$ 36

$ 66

$ 240

$ 46

$ 153

$ 388

$ 236

Income per share-basic:

$ 0.72

$ 0.86

$ 0.43

$ 0.33

$ 0.55

$ 0.97

$ 0.80

$ 0.55

$ 2.34

$ 2.87

$ 2.80

0.02

0.04

(0.02)

0.02

0.07

2.94

0.17

0.04

3.20

0.82

Income from continuing operations

0.74

0.90

0.43

0.31

0.57

1.04

3.74

0.72

2.38

6.07

3.62

Income per share-diluted:

0.71

0.86

0.42

0.33

0.54

0.96

0.78

0.55

2.32

2.83

2.77

0.02

0.04

(0.02)

0.02

0.06

2.92

0.16

0.04

3.16

0.80