Derivatives And Other Financial Instruments (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2011 USD ($)	Jun. 30, 2011 USD ($)	Sep. 30, 2011 USD ($)	Sep. 30, 2011 CAD	Sep. 30, 2011 Level 3 [Member] USD ($)	Jun. 30, 2011 Level 3 [Member] USD ($)	Dec. 31, 2010 Level 3 [Member] USD ($)
Net unrealized loss on derivative contracts					$ 574,000,000	$ 796,000,000	$ 779,000,000
Number of years of natural gas supply contract	6
Fair value of natural gas supply contract	5,000,000		5,000,000
Number of commodities subject to ceiling	2
Amount of aluminum designated as fair value hedges, kmt			310
Face amount of debt the hedges effectively convert from fixed to floating through 2018	515,000,000		515,000,000
Notional amount interest rate swaps		550,000,000
Gain on termination of interest rate swaps		33,000,000
Investment in foreign currency contract, foreign currency amount	$ 56,000,000		$ 56,000,000	58,000,000