Stockholders' Equity and Equity-Based Incentive Plans - Components of Accumulated Other Comprehensive Income (Loss) Reclassified (Detail) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 1,789
Net current period other comprehensive income		(33)
Ending Balance		3,596
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(49)	$ (42)
Other comprehensive income (loss) before reclassification		(20)	(1)
Amounts reclassified from AOCI	[1]		(6)
Net current period other comprehensive income		(20)	(7)
Ending Balance		(69)	(49)
Gain (Loss) on Derivative [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[2]	(2)	(25)
Other comprehensive income (loss) before reclassification	[2]	(16)	15
Acquisition of NCI	[2]		2
Amounts reclassified from AOCI	[1],[2]	3	3
Net current period other comprehensive income	[2]	(13)	20
Ending Balance	[2]	(15)	(5)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(51)	(67)
Other comprehensive income (loss) before reclassification		(36)	14
Acquisition of NCI			2
Amounts reclassified from AOCI	[1]	3	(3)
Net current period other comprehensive income		(33)	13
Ending Balance		$ (84)	$ (54)

[1] Amounts are net of tax, which was not material for the three- and nine-month periods ended September 30, 2018 and 2017.

[2] Refer to Note 17, Derivative Financial Instruments for additional details