Derivative Financial Instruments - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2018	May 08, 2018	Dec. 31, 2017
Derivative [Line Items]
Net gain (loss) on derivative financial instruments	$ (14,000,000)		$ (2,000,000)
Interest Rate Swap [Member]
Derivative [Line Items]
Net gain (loss) on derivative financial instruments	(10,000,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	(2,000,000)
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts		$ 1,940,000,000
Fair value of swap arrangement in net liability position	10,000,000
Term Facility [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts		$ 1,940,000,000
Foreign Exchange Rate [Member]
Derivative [Line Items]
Notional value of outstanding derivative contracts	$ 898,000,000
Derivative contracts, maturity date	Aug. 31, 2022
Fair value of derivative contracts	$ 5,000,000
Net gain (loss) on derivative financial instruments	(5,000,000)
Net deferred losses expected to be reclassified from AOCI over next 12 months	$ (3,000,000)