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Intangible Assets (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Intangible Assets [Abstract]      
International slot and route authorities indefinite life assets $ 708 $ 708  
Airport operating and gate lease rights, amortized life (in years) 25    
Airport operating and gate lease rights, residual value 0    
Amortization expense 27 28 28
Averaging annual amortization expense next five years $ 22