Debt (Details Textuals 2) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Debt Instrument [Line Items]
Term Loan deferred financing costs	$ 14
Payments of Debt Issuance Costs	22
Power generation capacity (in Megawatts)	11,064		13,553
Letters of credit issued	492	[1]	588	[1]
Term Loan New
Debt Instrument [Line Items]
Debt Instrument, Face Amount	360
Term Loan deferred financing costs	5
Russell City Project
Debt Instrument [Line Items]
Debt Instrument, Face Amount	845
Term Loan deferred financing costs	26
Power generation capacity (in Megawatts)	619
Construction Loan Facility	700
Project Letter of Credit Facility	77
Debt Service Letter of Credit Facility	68
Term Loan Period	10
Term loan interest rate added to LIBOR	2.25%
Amount Drawn Under Construction Loan	69
Letters of credit issued	$ 61

[1] When we entered into our Corporate Revolving Facility on December 10, 2010, the letters of credit issued under our First Lien Credit Facility were either replaced by letters of credit issued by the Corporate Revolving Facility or back-stopped by an irrevocable standby letter of credit issued by a third party. Our letters of credit issued under our Corporate Revolving Facility used for our commodity procurement and risk management activities at December 31, 2010 include those that were back-stopped of approximately $63 million. The back-stopped letters of credit were returned and extinguished during the first quarter of 2011.