Debt and Financing Costs - Components of Financing Costs, Net (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Debt Disclosure [Abstract]
Interest expense	$ 124	$ 146
Amortization of deferred loan costs	2	2
Capitalized interest	(95)	(90)
Interest income	(4)	(3)
Financing costs, net	$ 27	$ 55