v2.4.0.6
Summary of Significant Accounting Policies (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Restricted Cash and Cash Equivalents Items [Line Items]      
Held-to-maturity Securities, Restricted $ 25 $ 25  
Current 139 195  
Non-current 55 53  
Total 194 248  
Prior Period Reclassification Adjustment [Abstract]      
Ownership percentage in equity method investment 50.00%    
Reclassification adjustment on interest rate swaps   24  
Cash and cash equivalents subject to project finance facilities and lease agreements 306 269  
Inventory 294 262  
Property, plant and equipment, salvage value (as a percent) 10.00%    
Property, plant and equipment, salvage value of rotables (as a percent) 0.15%    
Impairment of long-lived assets held for use   95  
Impairment loss 0 116 4
Asset retirement obligations 27 51  
Decrease in ARO related to Revision of Expected Settlement Dates 24    
Debt Service
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 11 44  
Non-current 42 25  
Total 53 69  
Rent Reserve
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 0 22  
Non-current 0 5  
Total 0 27  
Construction Major Maintenance
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 33 35  
Non-current 10 14  
Total 43 49  
Security Project Insurance
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 79 75  
Non-current 0 7  
Total 79 82  
Other
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 16 19  
Non-current 3 2  
Total 19 21  
Greenfield [Member]
      
Prior Period Reclassification Adjustment [Abstract]      
Ownership percentage in equity method investment 50.00%    
Whitby [Member]
      
Prior Period Reclassification Adjustment [Abstract]      
Ownership percentage in equity method investment 50.00%    
Two Development Projects [Member]
      
Prior Period Reclassification Adjustment [Abstract]      
Impairment loss   $ 21