Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income (loss)	$ 199	$ (189)	$ 31
Cash flow hedging activities:
Gain (loss) on cash flow hedges before reclassification adjustment for cash flow hedges realized in net income (loss)	(61)	(69)	25
Reclassification adjustment for (gain) loss on cash flow hedges realized in net income (loss)	(20)	(25)	141
Unrealized actuarial losses arising during period	1	3	0
Foreign currency translation gain (loss)	3	(1)	2
Income tax (expense) benefit	9	45	(27)
Other comprehensive income (loss)	(70)	(53)	141
Comprehensive income (loss)	129	(242)	172
Comprehensive income attributable to the noncontrolling interest	0	(1)	0
Comprehensive income (loss) attributable to Calpine	$ 129	$ (243)	$ 172