Debt (Details 2) (USD $) In Millions, unless otherwise specified | 9 Months Ended | 9 Months Ended | |||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2011
Corporate Revolving Facility | Dec. 31, 2010
Corporate Revolving Facility | Sep. 30, 2011
Calpine Development Holdings, Inc. | Dec. 31, 2010
Calpine Development Holdings, Inc. | Sep. 30, 2011
NDH Project Debt credit facility | Dec. 31, 2010
NDH Project Debt credit facility | Sep. 30, 2011
Various project financing facilities | Dec. 31, 2010
Various project financing facilities | Sep. 30, 2011
Minimum | Sep. 30, 2011
Maximum | Sep. 30, 2011
One Month | Sep. 30, 2011
Two Months | Sep. 30, 2011
Three Months | Sep. 30, 2011
Six Months | Sep. 30, 2011
Nine Months | Sep. 30, 2011
Twelve Months | |||||||||
| Amounts issued under letter of credit facilities [Line Items] | |||||||||||||||||||||||||
| Fair value of amounts outstanding | $ 402 | [1] | $ 443 | [1] | $ 163 | $ 165 | [2] | $ 34 | [2] | $ 130 | $ 69 | ||||||||||||||
| Corporate Revolving Facility Interest Details [Abstract] | |||||||||||||||||||||||||
| Applicable margin range percentage above base rate | 2.00% | 2.25% | |||||||||||||||||||||||
| Percentage added to Federal Funds Effective Rate to arrive at base rate | 0.50% | ||||||||||||||||||||||||
| Interest periods for LIBOR rate borrowings | 1 | 2 | 3 | 6 | 9 | 12 | |||||||||||||||||||
| Applicable margin range percentage added to the British Bankers' Association Interest Settlement Rates | 3.00% | 3.25% | |||||||||||||||||||||||
| Unused commitment fee range percentage | 0.50% | 0.75% | |||||||||||||||||||||||
| |||||||||||||||||||||||||