Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents ($151 and $109 attributable to VIEs)	$ 962	$ 1,284
Accounts receivable, net of allowance of $2 and $6	483	437
Margin deposits and other prepaid expense	303	244
Restricted cash, current ($63 and $53 attributable to VIEs)	142	193
Derivative assets, current	514	339
Inventory and other current assets	352	335
Total current assets	2,756	2,832
Property, plant and equipment, net ($4,226 and $4,192 attributable to VIEs)	13,052	13,005
Restricted cash, net of current portion ($56 and $59 attributable to VIEs)	57	60
Investments in power plants	92	81
Long-term derivative assets	149	98
Other assets	463	473
Total assets	16,569	16,549
Current liabilities:
Accounts payable	437	382
Accrued interest payable	134	180
Debt, current portion ($81 and $39 attributable to VIEs)	144	115
Derivative liabilities, current	595	357
Other current liabilities	203	284
Total current liabilities	1,513	1,318
Debt, net of current portion ($2,682 and $2,660 attributable to VIEs)	10,633	10,635
Long-term derivative liabilities	289	293
Other long-term liabilities	257	247
Total liabilities	12,692	12,493
Commitments and contingencies (see Note 10)
Stockholders’ equity:
Preferred stock, $0.001 par value per share; authorized 100,000,000 shares, none issued and outstanding	0	0
Common stock, $0.001 par value per share; authorized 1,400,000,000 shares, 494,762,280 and 492,495,100 shares issued, respectively, and 455,000,065 and 457,048,970 shares outstanding, respectively	1	1
Treasury stock, at cost, 39,762,215 and 35,446,130 shares, respectively	(675)	(594)
Additional paid-in capital	12,351	12,335
Accumulated deficit	(7,625)	(7,500)
Accumulated other comprehensive loss	(236)	(248)
Total Calpine stockholders’ equity	3,816	3,994
Noncontrolling interest	61	62
Total stockholders’ equity	3,877	4,056
Total liabilities and stockholders’ equity	$ 16,569	$ 16,549