Accumulated Other Comprehensive Income (Loss) - Changes in Each Component of AOCI, Net of Tax (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2016 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,372
Other comprehensive income (loss) before reclassifications	(124)
Net other comprehensive items	(449)
Less: Noncontrolling interest	(4)
Ending Balance	1,277
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(227)
Other comprehensive income (loss) before reclassifications	(125)
Net other comprehensive items	(352)
Less: Noncontrolling interest	(4)
Ending Balance	(348)
Unrealized Gains on Investments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	2
Net other comprehensive items	2
Ending Balance	2
Pension and Other Postretirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(100)
Other comprehensive income (loss) before reclassifications	1
Net other comprehensive items	(99)
Ending Balance	(99)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(325)
Ending Balance	$ (445)