Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive Loss (Detail) $ in Millions	3 Months Ended
	Dec. 31, 2017 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 308
Ending balance	321
Foreign Currency Translation Gain (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(171)	[1]
Other comprehensive income	9	[1]
Ending balance	(162)	[1]
Minimum Pension Liability Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(10)
Ending balance	(10)
Deferred Losses On Derivative Financial Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive income	1
Ending balance	1
Accumulated Other Comprehensive Loss, net
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(181)
Other comprehensive income	10
Ending balance	$ (171)

[1] Includes historical foreign currency translation related to certain intra-entity transactions that are no longer considered of a long-term investment nature.