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Income Taxes - Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
U.S. federal and state, Current	$ 21	$ 14	$ 5
U.S. federal and state, Deferred	39	(31)	(156)
U.S. federal and state, Total	60	(17)	(151)
Foreign, Current	143	134	123
Foreign, Deferred	(7)	(6)	0
Foreign, Total	136	128	123
Provision (benefit) for income taxes	$ 196	$ 111	$ (28)

X

- Definition

The component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted federal and state tax law to the domestic taxable income (loss) from continuing operations.

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The component of total income tax expense for the period comprised of the net change during the period in the entity's domestic deferred tax assets and liabilities attributable to continuing operations as determined by applying the provisions of the federally enacted and state tax laws.

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The sum of the US federal and state current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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Amount of current foreign income tax expense (benefit) pertaining to income (loss) from continuing operations.

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Amount of current and deferred foreign income tax expense (benefit) attributable to income (loss) from continuing operations.

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