Income Tax - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Net discrete tax (benefits) expense related to tax settlements	$ 7	$ 3
Uncertain tax positions from expirations of statute of limitations	$ 1	$ 1
United States Internal Revenue Service (IRS) [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2020
United States Internal Revenue Service (IRS) [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2022
State Tax Authorities [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2016
State Tax Authorities [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2022
Foreign Jurisdictions [Member] | Earliest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2006
Foreign Jurisdictions [Member] | Latest Tax Year [Member]
Income Taxes [Line Items]
Tax years remain subject to examination	2022