Consolidated Statements of Operations (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010		Dec. 31, 2009
Operating revenues	$ 6,800	$ 6,545		$ 6,463
Operating expenses:
Fuel and purchased energy expense	4,349	3,974		3,897
Plant operating expense	904	868		868
Depreciation and amortization expense	550	570		456
Sales, general and other administrative expense	131	151		174
Other operating expense	87	100		101
Total operating expenses	6,021	5,663		5,496
Impairment losses	0	116		4
(Gain) on sale of assets, net	0	(119)		0
(Income) loss from unconsolidated investments in power plants	(21)	(16)		(50)
Income from operations	800	901		1,013
Interest expense	760	813		815
Loss on interest rate derivatives	145	223		0
Interest (income)	(9)	(11)		(16)
Debt extinguishment costs	94	91		76
Other (income) expense, net	21	15		13
Income (loss) before income taxes and discontinued operations	(211)	(230)		125
Income tax expense (benefit)	(22)	(68)	[1]	15
Income (loss) before discontinued operations	(189)	(162)		110
Discontinued operations, net of tax expense	0	193		35
Net income (loss)	(189)	31		145
Net (income) loss attributable to the noncontrolling interest	(1)	0		4
Net income (loss) attributable to Calpine	$ (190)	$ 31		$ 149
Basic earnings (loss) per common share attributable to Calpine:
Weighted average shares of common stock outstanding (in thousands)	485,381	486,044		485,659
Income (loss) before discontinued operations attributable to Calpine	$ (0.39)	$ (0.33)		$ 0.24
Discontinued operations, net of tax expense, attributable to Calpine	$ 0.00	$ 0.39		$ 0.07
Net income (loss) per common share attributable to Calpine — basic	$ (0.39)	$ 0.06		$ 0.31
Diluted earnings (loss) per common share attributable to Calpine:
Weighted average shares of common stock outstanding (in thousands)	485,381	487,294		486,319
Income (loss) before discontinued operations attributable to Calpine	$ (0.39)	$ (0.33)		$ 0.24
Discontinued operations, net of tax expense, attributable to Calpine	$ 0.00	$ 0.39		$ 0.07
Net income (loss) per common share attributable to Calpine — diluted	$ (0.39)	$ 0.06		$ 0.31

[1] Includes approximately $13 million in intraperiod tax expense related to a prior period with an offsetting benefit in OCI.