Derivative Financial Instruments - Schedule of Total Value by Underlying Risk Recognized in Other Comprehensive Income and Reclassified from AOCI to Statement of Operations (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		$ (58)	$ (1)
Revenues	[1]	2,211	608
Cost of operations		2,018	476
Interest expense, net		(92)	(12)
Designated as Hedging Instrument [Member] | Foreign Exchange Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		(7)	$ 1
Revenues		1
Cost of operations		1
Designated as Hedging Instrument [Member] | Interest Rate Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)		(15)
Interest expense, net		1
Derivatives not Designated as Hedges [Member] | Foreign Exchange Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Revenues		$ 1

[1] Intercompany amounts have been eliminated in consolidation.