Consolidated Statements of Operations (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating revenues:
Commodity revenue	$ 7,595	$ 6,374	$ 5,417
Mark to Market Gain Loss on Derivatives included in Operating Revenues	419	(86)	48
Other revenue	16	13	13
Operating revenues	8,030	6,301	5,478
Operating expenses:
Commodity expense	4,815	3,808	2,894
Mark to Market Gain Loss on Derivatives Included in Fuel and Purchased Energy Expense	77	(72)	130
Fuel and purchased energy expense	4,892	3,736	3,024
Plant operating expense	969	895	922
Depreciation and amortization expense	603	593	562
Sales, general and other administrative expense	144	136	140
Other operating expenses	88	81	78
Total operating expenses	6,696	5,441	4,726
Impairment losses	123	16	0
(Gain) on sale of assets, net	(753)	0	(222)
(Income) from unconsolidated investments in power plants	(25)	(30)	(28)
Income from operations	1,989	874	1,002
Interest expense	645	696	736
Loss on interest rate derivatives	0	0	14
Interest (income)	(6)	(6)	(11)
Debt extinguishment costs	346	144	30
Other (income) expense, net	21	20	15
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	983	20	218
Income tax expense	22	2	19
Net income	961	18	199
Net income attributable to the noncontrolling interest	(15)	(4)	0
Net income attributable to Calpine	$ 946	$ 14	$ 199
Basic earnings per common share attributable to Calpine:
Weighted average shares of common stock outstanding (in shares)	404,837	440,666	467,752
Net income (loss) per common share attributable to Calpine — basic (in dollars per share)	$ 2.34	$ 0.03	$ 0.43
Diluted earnings per common share attributable to Calpine:
Weighted average shares of common stock outstanding (in shares)	409,360	444,773	471,343
Net income (loss) per common share attributable to Calpine — diluted (in dollars per share)	$ 2.31	$ 0.03	$ 0.42