Derivatives And Other Financial Instruments (Schedule Of Gain Or Loss On Hedged Items And Derivative Contracts) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ (62)	$ 128	$ 275
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	102	(103)	(288)
Aluminum Contracts [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	(126)	38	214
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	133	(41)	(227)
Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	64	90	61
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	$ (31)	$ (62)	$ (61)