Derivative Instruments (Details 5) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense		$ 157	$ 158	$ 314	$ 312
Interest Rate Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	[1],[2]	(6)	14	(18)	8
Interest expense	[3]	0	0	1	1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Rate Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	[1],[2],[4]	$ (11)	$ (12)	$ (22)	$ (24)

[1] We did not record any material gain (loss) on hedge ineffectiveness related to our interest rate hedging instruments designated as cash flow hedges during the three and six months ended June 30, 2016 and 2015.

[2] We recorded an income tax expense of nil for each of the three and six months ended June 30, 2016 and 2015, in AOCI related to our cash flow hedging activities.

[3] In addition to changes in market value on derivatives not designated as hedges, changes in mark-to-market gain (loss) also includes hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.

[4] Cumulative cash flow hedge losses attributable to Calpine, net of tax, remaining in AOCI were $143 million and $127 million at June 30, 2016 and December 31, 2015, respectively. Cumulative cash flow hedge losses attributable to the noncontrolling interest, net of tax, remaining in AOCI were $13 million and $11 million at June 30, 2016 and December 31, 2015, respectively.