Stockholders' Equity - Schedule of Activity in Noncontrolling Interests (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity [Abstract]
Balance at September 30			$ 104	$ 122
Net income attributable to noncontrolling interests	$ 4	$ 2	12	7
Noncontrolling interest foreign currency translation adjustment	(3)		(5)	(3)
Noncontrolling interest dividends declared			(16)	(22)
Balance at June 30	$ 95	$ 104	$ 95	$ 104