Derivatives And Other Financial Instruments (Schedule Of Net Fair Values Of Outstanding Derivative Contracts And Effect Of Hypothetical Change (Increase Or Decrease Of 10%) In Market Prices Or Rates) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Aluminum Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value asset/(liability)	$ (648)
Index change of + / - 10%	137
Embedded Credit Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value asset/(liability)	(28)
Index change of + / - 10%	9
Energy Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value asset/(liability)	2
Index change of + / - 10%	375
Foreign Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value asset/(liability)	1
Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value asset/(liability)	30
Index change of + / - 10%	$ 2