Accumulated Other Comprehensive Income (Loss) ("AOCI") - Changes in Each Component of AOCI, Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,407	$ 1,032
Ending Balance	1,475	1,159
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(353)	(429)
Other comprehensive income (loss) before reclassifications	62	88
Amounts reclassified from AOCI	(1)	(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	4	6
Ending Balance	(296)	(348)
Pension and Other Postretirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(9)	(10)
Ending Balance	(9)	(10)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(362)	(439)
Other comprehensive income (loss) before reclassifications	62	88
Amounts reclassified from AOCI	(1)	(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	4	6
Ending Balance	$ (305)	$ (358)