v2.4.1.9

Variable Interest Entities and Unconsolidated Investments in Power Plants Condensed Financial Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating revenues	$ 1,646us-gaap_Revenues	$ 1,965us-gaap_Revenues
Costs and Expenses	1,485us-gaap_CostsAndExpenses	1,830us-gaap_CostsAndExpenses
Net income (loss)	(7)us-gaap_ProfitLoss	(13)us-gaap_ProfitLoss
Whitby [Member]
Operating revenues	15us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember	15us-gaap_Revenues / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember
Costs and Expenses	9us-gaap_CostsAndExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember	7us-gaap_CostsAndExpenses / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember
Net income (loss)	$ 6us-gaap_ProfitLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember	$ 8us-gaap_ProfitLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = cpn_WhitbyMember

X

- Definition

Total costs of sales and operating expenses for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688



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-Publisher SEC

-Name Regulation S-X (SX)

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