Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021
Derivatives, Fair Value [Line Items]
Companys hedged interest rate transactions				2 years
Deferred (losses) gains on derivative financial instruments	$ 5,000,000		$ 3,000,000	$ 26,000,000	$ 9,000,000
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Outstanding hedge contracts	820,000,000			820,000,000		$ 820,000,000
Deferred gain (loss) on derivative financial instruments				9,000,000
Deferred (losses) gains on derivative financial instruments		$ (17,000,000)
Unrealized pre-tax (losses) gains on derivative financial instruments				34,000,000	12,000,000
Foreign Exchange Contract | Other Income (Expense)
Derivatives, Fair Value [Line Items]
Realized foreign exchange forward contract gain (loss)				6,000,000	(4,000,000)
Unrealized foreign exchange forward contract gain (loss)				3,000,000	$ 0
Sale
Derivatives, Fair Value [Line Items]
Outstanding hedge contracts	148,000,000			148,000,000
Purchase
Derivatives, Fair Value [Line Items]
Outstanding hedge contracts	$ 112,000,000			$ 112,000,000