v2.4.0.8

Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 MWh MMBTU | Dec. 31, 2012 MWh MMBTU
Derivative Instruments [Abstract] |  |
Power (MWh) | (29) | (16)
Natural gas (MMBtu) | 448 | 66
Interest rate swaps | $ 1,527 | $ 1,602

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- Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:stringItemType
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Period Type: | duration

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- Definition Nonmonetary Notional Amount of Price Risk Derivatives Natural Gas + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | num:energyItemType
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Period Type: | instant

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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Data Type: | xbrli:monetaryItemType
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Period Type: | instant

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- Definition Nominal energy measure used to calculate payments on a derivative instrument. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
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Period Type: | duration