Accumulated Other Comprehensive Income (Loss) - Changes in Each Component of AOCI, Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance			$ 1,372		$ 1,372
Other comprehensive income (loss)	$ 54	$ 57	(124)	$ (14)	(13)	$ 4
Less: Other comprehensive income (loss) attributable to noncontrolling interests	3	1	(4)
Ending Balance	1,477				1,477
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(293)	(348)	(227)		(227)
Other comprehensive income (loss)	54	56	(125)
Less: Other comprehensive income (loss) attributable to noncontrolling interests	3	1	(4)
Ending Balance	(242)	(293)	(348)		(242)
Unrealized Gains on Investments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	2	2	2		2
Ending Balance	2	2	2		2
Pension and Other Postretirement Benefit Liability Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(98)	(99)	(100)		(100)
Other comprehensive income (loss)		1	1
Ending Balance	(98)	(98)	(99)		(98)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(389)	(445)	(325)		(325)
Ending Balance	$ (338)	$ (389)	$ (445)		$ (338)