Long-Term Debt - Summary of Movement in Deferred Financing Costs (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Disclosure [Abstract]
Balance as of January 1	$ 74	$ 98	$ 37
Capitalization of debt finance costs	29	13	84
Amortization	(24)	(37)	(23)
Written-off as loss on extinguishment	(39)
Balance as of December 31	$ 40	$ 74	$ 98