v2.4.0.6
Debt (Corporate Revolving Facility and other Letters of Credit Facilities) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Line of Credit Facility [Line Items]    
Line of Credit Facility, Fair Value of Amount Outstanding $ 626 $ 763
Corporate Revolving Facility [Member]
   
Line of Credit Facility [Line Items]    
Line of Credit Facility, Fair Value of Amount Outstanding 243 440
CDH [Member]
   
Line of Credit Facility [Line Items]    
Line of Credit Facility, Fair Value of Amount Outstanding 253 193
Various Project Financing Facilities [Member]
   
Line of Credit Facility [Line Items]    
Line of Credit Facility, Fair Value of Amount Outstanding $ 130 $ 130