v2.4.0.6
Summary of Significant Accounting Policies (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Dec. 31, 2011
Restricted Cash and Cash Equivalents Items [Line Items]      
Operating Leases, Future Minimum Payments Receivable, Current     $ 395
Interest Costs, Capitalized During Period 8 7  
Held-to-maturity Securities, Restricted 25   25
Current 119   139
Non-current 52   55
Total 171   194
Prior Period Reclassification Adjustment [Abstract]      
Cash and cash equivalents subject to project finance facilities and lease agreements 171   306
Inventory 256   294
Operating Leases, Future Minimum Payments Receivable, in Two Years     527
Operating Leases, Future Minimum Payments Receivable, in Three Years     452
Operating Leases, Future Minimum Payments Receivable, in Four Years     461
Operating Leases, Future Minimum Payments Receivable, in Five Years     375
Operating Leases, Future Minimum Payments Receivable, Thereafter     2,269
Operating Leases, Future Minimum Payments Receivable     4,479
Debt Service
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 14   11
Non-current 41   42
Total 55   53
Rent Reserve
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 3   0
Non-current 0   0
Total 3   0
Construction Major Maintenance
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 38   33
Non-current 7   10
Total 45   43
Security Project Insurance
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 51   79
Non-current 1   0
Total 52   79
Other
      
Restricted Cash and Cash Equivalents Items [Line Items]      
Current 13   16
Non-current 3   3
Total $ 16   $ 19
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%