Interest Cost Components - Schedule of Interest Cost Components (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Disclosure [Abstract]
Amount charged to expense	$ 453	$ 490	$ 524
Amount capitalized	99	93	101
Interest costs, total	$ 552	$ 583	$ 625