Employee Benefit Plans - Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Pension Benefits [Member] | U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accounts payable and accrued liabilities		$ (1)
Other liabilities	$ (2)	(2)
Pension Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Other assets	26	35
Accounts payable and accrued liabilities	(1)	(1)
Other liabilities	(23)	(38)
Postretirement Benefits [Member] | U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accounts payable and accrued liabilities	(2)	(3)
Other liabilities	(14)	(22)
Postretirement Benefits [Member] | Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accounts payable and accrued liabilities	(1)	(1)
Other liabilities	$ (12)	$ (18)