Financial Instruments - Impact of Changes in Fair Value of Derivatives (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivatives, Fair Value [Line Items]
Derivative Instruments, Amount of Gain (Loss) Recognized Income (Loss)	$ 7	$ 1	$ (7)	$ (11)
Derivatives designated as hedging instruments [Member] | Interest rate caps [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Amount of Gain (Loss) Recognized in Other Comprehensive Income (Loss)	(2)		(2)
Derivatives designated as hedging instruments [Member] | Interest rate caps [Member] | Interest expense, net [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Amount of Gain (Loss) Recognized Income (Loss)
Derivatives not designated as hedging instruments [Member] | Interest rate swaps [Member] | Interest expense, net [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Amount of Gain (Loss) Recognized Income (Loss)		(2)	(3)	(3)
Derivatives not designated as hedging instruments [Member] | Foreign currency contracts [Member] | Selling, general and administrative [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Amount of Gain (Loss) Recognized Income (Loss)	$ 7	$ 3	$ (4)	$ (8)