Derivatives And Other Financial Instruments (Schedule Of Gain Or Loss On Hedged Items And Derivative Contracts) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	$ 39	$ 60
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	(51)	(63)
Aluminum Contracts [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	36	49
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	(48)	(52)
Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Earnings on Derivatives	3	11
Amount of Gain or (Loss) Recognized in Earnings on Hedged Items	$ (3)	$ (11)