Financial Instruments and Fair Value Measurements - Summary of Activity in Interest Rate Swaps (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Notional amounts at January 1		$ 333,500,000
Notional amounts at December 31			$ 333,500,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Notional amounts at January 1	$ 398,000,000	71,000,000	1,315,000,000
New contracts	1,396,000,000	398,000,000
Matured or expired contracts	(360,000,000)	(71,000,000)	(1,244,000,000)
Notional amounts at December 31	$ 1,434,000,000	$ 398,000,000	$ 71,000,000