Derivatives and Other Financial Instruments - Schedule of Gain or Loss on Hedged Items and Derivative Contracts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ (132)	$ 1	$ (62)
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	133	(19)	102
Aluminum Contracts [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(142)	(9)	(126)
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	143	(9)	133
Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	10	10	64
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	$ (10)	$ (10)	$ (31)