v2.4.0.6
Variable Interest Entities and Unconsolidated Investments (Unconsolidated VIEs) (Details) (USD $)
In Millions, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]    
Equity Method Investments $ 79 $ 80
Greenfield [Member]
   
Schedule of Equity Method Investments [Line Items]    
Equity Method Investments 70 72
Equity Method Investment, Ownership Percentage 50.00%  
Whitby [Member]
   
Schedule of Equity Method Investments [Line Items]    
Equity Method Investments $ 9 $ 8
Equity Method Investment, Ownership Percentage 50.00%