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Properties, Plants, And Equipment, Net (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2011
MT
Dec. 31, 2010
MT
Property, Plant and Equipment [Line Items]    
Net carrying value of assets   $ 152
Smelting Assets [Member]
    
Property, Plant and Equipment [Line Items]    
Net carrying value of assets 166 306
Idle capacity of assets, units 353,000 587,000
Net carrying value of other idled smelting assets written off 291,000  
Idled Refining [Member]
    
Property, Plant and Equipment [Line Items]    
Net carrying value of assets $ 65 $ 100
Idle capacity of assets, units 1,177,000 1,321,000