Property and Equipment, Net - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Property Plant And Equipment [Abstract]
Depreciation expense	$ 37	$ 29	$ 74	$ 61
Net capital lease assets	94		94		104
Interest on capital projects capitalized	$ 3	$ 1	$ 5	$ 2