Stockholders' Equity - Schedule of Activity in Noncontrolling Interests (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Balance at September 30			$ 98	$ 104
Net income (loss) attributable to noncontrolling interests, net of tax	$ 8	$ 4	18	12
Foreign currency translation adjustment attributable to noncontrolling interests, net of tax	3	(3)		(5)
Dividends declared to noncontrolling interests			(14)	(16)
Contribution from noncontrolling interest			2
Balance at June 30	$ 104	$ 95	$ 104	$ 95