Debt (Textuals) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Gains (Losses) on Extinguishment of Debt	$ (30,000,000)	$ (94,000,000)	$ (91,000,000)
Maximum Remaining Lease Term	36
Lease Assets, Historical Cost	880,000,000	879,000,000
Lease Assets, Accumulated Depreciation	312,000,000	318,000,000
2019 First Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument Redemption Premium Percentage	10.00%
Redemption amount percentage	103.00%
Debt Instrument, Face Amount	835,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.50%
Gains (Losses) on Extinguishment of Debt	18,000,000
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
First Lien Notes 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.25%
First Lien Notes 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.00%
CCFC Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage			8.00%
Number of power plants			6
Debt, Weighted Average Interest Rate		8.90%	8.90%
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] | 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]
Letter of Credit Total	300,000,000
Cash collateralize letters of credit issued	225,000,000
Pledged Financial Instruments, Not Separately Reported, Securities for Letter of Credit Facilities	$ 28,000,000
One Month [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	1 month
Two Months [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	2 months
Three Months [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	3 months
Six Months [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	6 months
Nine Months [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	9 months
Twelve Months [Member] | Corporate Revolving Facility [Member]
Debt Instrument [Line Items]
Interest periods for LIBOR rate borrowings	12 months