Commitments and Contingencies (Schedule of Guarantor Obligations) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Loans Payable [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Balance On First Anniversary	$ 37	[1]
Guarantee Obligations Balance On Second Anniversary	36	[1]
Guarantee Obligations Balance On Third Anniversary	26	[1]
Guarantee Obligations Balance On Fourth Anniversary	31	[1]
Guarantee Obligations Balance On Fifth Anniversary	30	[1]
Guarantee Obligations Due After Five Years	148	[1]
Guarantor Obligations, Maximum Exposure, Undiscounted	308	[1]
Financial Standby Letter of Credit [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Balance On First Anniversary	572	[2],[3],[4]
Guarantee Obligations Balance On Second Anniversary	14	[2],[3],[4]
Guarantee Obligations Balance On Third Anniversary	20	[2],[3],[4]
Guarantee Obligations Balance On Fourth Anniversary	0	[2],[3],[4]
Guarantee Obligations Balance On Fifth Anniversary	0	[2],[3],[4]
Guarantee Obligations Due After Five Years	38	[2],[3],[4]
Guarantor Obligations, Maximum Exposure, Undiscounted	644	[2],[3],[4]
Surety Bonds [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Balance On First Anniversary	0	[2],[5],[6]
Guarantee Obligations Balance On Second Anniversary	0	[2],[5],[6]
Guarantee Obligations Balance On Third Anniversary	0	[2],[5],[6]
Guarantee Obligations Balance On Fourth Anniversary	0	[2],[5],[6]
Guarantee Obligations Balance On Fifth Anniversary	0	[2],[5],[6]
Guarantee Obligations Due After Five Years	4	[2],[5],[6]
Guarantor Obligations, Maximum Exposure, Undiscounted	4	[2],[5],[6]
Greenleaf [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Balance On First Anniversary	4	[2]
Guarantee Obligations Balance On Second Anniversary	0	[2]
Guarantee Obligations Balance On Third Anniversary	0	[2]
Guarantee Obligations Balance On Fourth Anniversary	0	[2]
Guarantee Obligations Balance On Fifth Anniversary	0	[2]
Guarantee Obligations Due After Five Years	0	[2]
Guarantor Obligations, Maximum Exposure, Undiscounted	4	[2]
Gurantee Obligations Total [Member]
Guarantor Obligations [Line Items]
Guarantee Obligations Balance On First Anniversary	613
Guarantee Obligations Balance On Second Anniversary	50
Guarantee Obligations Balance On Third Anniversary	46
Guarantee Obligations Balance On Fourth Anniversary	31
Guarantee Obligations Balance On Fifth Anniversary	30
Guarantee Obligations Due After Five Years	190
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 960

[1] Represents Calpine Corporation guarantees of certain power plant capital leases and related interest. All guaranteed capital leases are recorded on our Consolidated Balance Sheets.

[2] These are contingent off balance sheet obligations.

[3] Letters of credit are renewed annually and as such all amounts are reflected in the year of letter of credit expiration. The related commercial obligations extend for multiple years, therefore, renewal of the letter of credit will likely follow the term of the associated commercial obligation.

[4] The standby letters of credit disclosed above represent those disclosed in Note 6.

[5] The majority of surety bonds do not have expiration or cancellation dates.

[6] As of December 31, 2014, $2 million of cash collateral is outstanding related to these bonds.