Financial Instruments and Fair Value Measurements - Foreign Currency Contracts Activity (Detail) - Forwards [Member]	9 Months Ended
	Sep. 30, 2018 USD ($) Derivative	Sep. 30, 2017 USD ($) Derivative
BRL
Derivative [Line Items]
Notional amounts at January 1	$ 0
New contracts	157,000,000
Matured, expired or settled contracts	0
Notional amounts at September 30	$ 157,000,000
Weighted average forward rate at September 30	2.60
Active contracts at September 30 | Derivative	3
CAD
Derivative [Line Items]
Notional amounts at January 1	$ 99,000,000	$ 100,000,000
New contracts	100,000,000	99,000,000
Matured, expired or settled contracts	(99,000,000)	(100,000,000)
Notional amounts at September 30	$ 100,000,000	$ 99,000,000
Weighted average forward rate at September 30	1.28	1.34
Active contracts at September 30 | Derivative	2	2
EUR
Derivative [Line Items]
Notional amounts at January 1	$ 0
New contracts	1,053,000,000
Matured, expired or settled contracts	(1,053,000,000)
Notional amounts at September 30	$ 0
Weighted average forward rate at September 30	0
Active contracts at September 30 | Derivative	0
GBP
Derivative [Line Items]
Notional amounts at January 1		$ 46,000,000
New contracts		127,000,000
Matured, expired or settled contracts		(173,000,000)
Notional amounts at September 30		$ 0
Weighted average forward rate at September 30		0
Active contracts at September 30 | Derivative		0