Derivative Financial Instruments - Schedule of Total Value by Underlying Risk Recognized in Other Comprehensive Income and Reclassified from AOCI to Cost of Operations and Interest Expense, Net in Statement of Operations (Detail) - Designated as Hedging Instrument [Member] - Cash Flow Hedging [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Foreign Currency Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (14)	$ 16	$ 4
Foreign Currency Hedges [Member] | Cost of operations [Member]
Derivative Instruments Gain Loss [Line Items]
Loss (gain) reclassified from AOCI	7	5	35
Foreign Currency Hedges [Member] | Other non-operating expense [Member]
Derivative Instruments Gain Loss [Line Items]
Ineffective portion and amount excluded from effectiveness testing: gain (loss) recognized in Other non-operating income (expense)	(2)	$ (1)	$ (1)
Interest Rate Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	(32)
Interest Rate Hedges [Member] | Interest Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Loss (gain) reclassified from AOCI	$ 1