v2.4.0.6
Debt (Debt Textuals) (Details) (USD $)
3 Months Ended 9 Months Ended
Sep. 30, 2012
MW
Sep. 30, 2011
Sep. 30, 2012
MW
Sep. 30, 2011
Dec. 31, 2011
MW
Debt Instrument [Line Items]          
Gains (Losses) on Extinguishment of Debt $ 0 $ 4,000,000 $ (12,000,000) $ (94,000,000)  
Power generation capacity 10,500   10,500   11,391
Letters of Credit Outstanding, Amount 685,000,000   685,000,000   763,000,000
2019 First Lien Term Loan [Member]
         
Debt Instrument [Line Items]          
Redemption amount percentage     10.00%    
Debt Instrument Redemption Premium Percentage     103.00%    
Debt Instrument, Face Amount 835,000,000   835,000,000    
Gains (Losses) on Extinguishment of Debt     18,000,000    
Debt Instrument, Interest Rate, Stated Percentage 4.50%   4.50%    
First Lien Term Loans [Member]
         
Debt Instrument [Line Items]          
Term loan interest rate spread option Federal Funds effective rate     0.50%    
Term loan interest rate spread option Prime Rate     2.25%    
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum     3.25%    
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum     1.25%    
Percentage of principal amount of Term Loan to be paid quarterly     0.25%    
BRSP [Member]
         
Debt Instrument [Line Items]          
Debt Instrument, Face Amount 218,000,000   218,000,000    
Russell City Project [Member]
         
Debt Instrument [Line Items]          
Debt Instrument, Face Amount 845,000,000   845,000,000    
Power generation capacity 619   619    
Long-term Construction Loan, Noncurrent 700,000,000   700,000,000    
Project Letter of Credit Facility 77,000,000   77,000,000    
Term Loan Period 10 years   10 years    
Debt Service Letter of Credit Facility 68,000,000   68,000,000    
Amount Drawn Under Construction Loan 468,000,000   468,000,000    
Noncontrolling Interest, Ownership Percentage by Parent 75.00%   75.00%    
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 25.00%   25.00%    
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates     2.25%    
Letters of Credit Outstanding, Amount 61,000,000   61,000,000    
Los Esteros Project [Member]
         
Debt Instrument [Line Items]          
Debt Instrument, Face Amount 373,000,000   373,000,000    
Power generation capacity 188   188    
Power generation capacity after upgrade 309   309    
Long-term Construction Loan, Noncurrent 305,000,000   305,000,000    
Project Letter of Credit Facility 38,000,000   38,000,000    
Term Loan Period 10 years   10 years    
Debt Service Letter of Credit Facility 30,000,000   30,000,000    
Amount Drawn Under Construction Loan 171,000,000   171,000,000    
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates     2.25%    
Letters of Credit Outstanding, Amount 30,000,000   30,000,000    
Corporate Revolving Facility [Member]
         
Debt Instrument [Line Items]          
Percentage added to Federal Funds Effective Rate to arrive at base rate     0.50%    
Repayment time for drawings under letters of credit     2 days    
Excess amount of asset sales requiring mandatory prepayments     3,000,000,000    
Corporate Revolving Facility [Member] | One Month [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     1 month    
Corporate Revolving Facility [Member] | Two Months [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     2 months    
Corporate Revolving Facility [Member] | Three Months [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     3 months    
Corporate Revolving Facility [Member] | Six Months [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     6 months    
Corporate Revolving Facility [Member] | Nine Months [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     9 months    
Corporate Revolving Facility [Member] | Twelve Months [Member]
         
Debt Instrument [Line Items]          
Interest periods for LIBOR rate borrowings     12 months    
Corporate Revolving Facility [Member] | Minimum [Member]
         
Debt Instrument [Line Items]          
Applicable margin range percentage above base rate     2.00%    
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates     3.00%    
Unused commitment fee range percentage     0.50%    
Corporate Revolving Facility [Member] | Maximum [Member]
         
Debt Instrument [Line Items]          
Applicable margin range percentage above base rate     2.25%    
Applicable Margin Range Percentage Above British Bankers' Association Interest Settlement Rates     3.25%    
Unused commitment fee range percentage     0.75%    
CDHI [Member]
         
Debt Instrument [Line Items]          
Upsize Facility Total     $ 300,000,000    
First Lien Notes 2017 [Member]
         
Debt Instrument [Line Items]          
Debt Instrument, Interest Rate, Stated Percentage 7.25%   7.25%    
First Lien Notes 2019 [Member]
         
Debt Instrument [Line Items]          
Debt Instrument, Interest Rate, Stated Percentage 8.00%   8.00%