Derivative Instruments (Details 4) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Loss) Recognized in OCI (Effective Portion)	$ (9)	[1]	$ 48	[1]	$ (9)	[1]	$ 61	[1]
Gain (Loss) Reclassified from AOCI into Income (EffectivePortion)	(13)	[1],[2]	(10)	[1],[2]	(26)	[1],[2]	(19)	[1],[2]
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Loss) Recognized in OCI (Effective Portion)	(9)	[3]	48	[3]	(9)	[3]	61	[3]
Gain (Loss) Reclassified from AOCI into Income (EffectivePortion)	$ (13)	[2],[3],[4]	$ (10)	[2],[3]	$ (26)	[2],[3],[4]	$ (19)	[2],[3]

[1] We recorded an income tax benefit of nil for each of the three and six months ended June 30, 2014, and income tax benefit of $2 million and $3 million for the three and six months ended June 30, 2013, respectively, in AOCI related to our cash flow hedging activities.

[2] Cumulative cash flow hedge losses attributable to Calpine, net of tax, remaining in AOCI were $156 million and $148 million at June 30, 2014 and December 31, 2013, respectively. Cumulative cash flow hedge losses attributable to the noncontrolling interest, net of tax, remaining in AOCI were $12 million and $11 million at June 30, 2014 and December 31, 2013, respectively.

[3] We did not record any gain (loss) on hedge ineffectiveness related to our interest rate swaps designated as cash flow hedges during the three and six months ended June 30, 2014 and 2013.

[4] Includes a loss of $5 million and $10 million that was reclassified from AOCI to interest expense for the three and six months ended June 30, 2014, respectively, where the hedged transactions are no longer expected to occur.