Accumulated Other Comprehensive Income (Loss) - Changes in Each Component of AOCI, Net of Tax (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2020 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 814
Ending Balance	962
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(307)
Other comprehensive income (loss) before reclassifications	94
Amounts reclassified from AOCI	(1)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	7
Ending Balance	(221)
Pension and Other Postretirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(44)
Other comprehensive income (loss) before reclassifications	(1)
Amounts reclassified from AOCI	4
Ending Balance	(41)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(351)
Other comprehensive income (loss) before reclassifications	93
Amounts reclassified from AOCI	3
Less: Other comprehensive income (loss) attributable to noncontrolling interests	7
Ending Balance	$ (262)