Charges on sale of trade receivables.

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Valuation allowances are provided against deferred tax assets where management believes that the Company has a 50% or less chance of utilizing the associated benefit in the future.

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Significant accounting policies.

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Standard payment term for revenue.

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- Definition

Amount, after allowance for credit loss, of accounts and financing receivable. Includes, but is not limited to, notes and loan receivable.

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Amount of increase (decrease) in allowance for credit loss on accounts receivable.

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Future cash outflow to pay for purchases of fixed assets that have occurred.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement.

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Amount of interest capitalized, including amount of allowance for funds used during construction.

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Amount of dividend income on nonoperating securities.

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The new date of the annual goodwill impairment test.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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The reason for any change to the date of the annual goodwill impairment test.

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Significant Accounting Policies - Additional Information (Detail) ¥ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2019 CNY (¥)	Sep. 30, 2018 CNY (¥)
Significant Accounting Policies [Line Items]
Equity affiliate investments	$ 39,000,000		$ 39,000,000	$ 52,000,000
Changed date of annual impairment test	August 31
Reason for change in date of annual goodwill impairment test			This date is preferred as it better aligns with the Company’s planning process, which produces a significant input to the testing, and it did not result in a material change to the Company’s consolidated financial statements.
Capitalized interest			$ 4,000,000	2,000,000	$ 1,000,000
Asset retirement obligation reserve	$ 26,000,000		26,000,000	28,000,000
Charges on sale of notes receivables			3,000,000	3,000,000	2,000,000
Changes in allowance			$ 0	0
Chance of utilizing the associated benefit for valuation allowances, maximum			50.00%
Accounts Payable and Accrued Liabilities [Member]
Significant Accounting Policies [Line Items]
Capital expenditures			$ 23,000,000	29,000,000	7,000,000
Equity Method Investments [Member]
Significant Accounting Policies [Line Items]
Dividends declared			$ 4,000,000	9,000,000	11,000,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Payment terms			0 days
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
Minimum [Member] \| Cabot [Member]
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%		20.00%			20.00%
Maximum [Member]
Significant Accounting Policies [Line Items]
Payment terms			90 days
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
Maximum [Member] \| Cabot [Member]
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%		50.00%			50.00%
Other Nonoperating Income (Expense) [Member]
Significant Accounting Policies [Line Items]
Foreign currency transaction gains (losses)				(4,000,000)	$ (4,000,000)
Other Nonoperating Income (Expense) [Member] \| Maximum [Member]
Significant Accounting Policies [Line Items]
Foreign currency transaction gains (losses)			$ 1,000,000
Venezuela [Member] \| Carbon Black Affiliate [Member]
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage		49.00%
Venezuela [Member] \| Carbon Black Affiliate [Member] \| Other Nonoperating Income (Expense) [Member]
Significant Accounting Policies [Line Items]
Impairment charge		$ 11,000,000
China [Member]
Significant Accounting Policies [Line Items]
Accounts and notes receivable, net	$ 4,000,000		$ 4,000,000	$ 5,000,000		¥ 30	¥ 32