Stockholders' Equity and Equity-Based Incentive Plans - Components of Accumulated Other Comprehensive Income (Loss) Reclassified (Detail) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 1,789
Net current period other comprehensive income		(24)
Ending Balance		3,566
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(49)	$ (42)
Other comprehensive income (loss) before reclassification		(12)
Net current period other comprehensive income		(12)
Ending Balance		(61)	(42)
Gain (Loss) on Derivative [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(2)	(25)
Other comprehensive income (loss) before reclassification	[1]	(15)	10
Acquisition of NCI	[1]		2
Amounts reclassified from AOCI	[1],[2]	3	(1)
Net current period other comprehensive income	[1]	(12)	11
Ending Balance	[1]	(14)	(14)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(51)	(67)
Other comprehensive income (loss) before reclassification		(27)	10
Acquisition of NCI			2
Amounts reclassified from AOCI	[2]	3	(1)
Net current period other comprehensive income		(24)	11
Ending Balance		$ (75)	$ (56)

[1] Refer to Note 16, Derivative Financial Instruments for additional details

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