v2.4.0.8

Variable Interest Entities and Unconsolidated Investments (VIE Texuals) (Details) | 3 Months Ended | 6 Months Ended |  | 3 Months Ended | 6 Months Ended |  | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2013 USD ($) MW | Jun. 30, 2012 USD ($) | Jun. 30, 2013 USD ($) MW | Jun. 30, 2012 USD ($) | Dec. 31, 2012 USD ($) MW | Jun. 30, 2013 Greenfield [Member] USD ($) | Jun. 30, 2012 Greenfield [Member] USD ($) | Jun. 30, 2013 Greenfield [Member] USD ($) | Jun. 30, 2012 Greenfield [Member] USD ($) | Jun. 30, 2013 Greenfield [Member] CAD MW | Jun. 30, 2013 Whitby [Member] USD ($) MW | Jun. 30, 2012 Whitby [Member] USD ($) | Jun. 30, 2013 Whitby [Member] USD ($) MW | Jun. 30, 2012 Whitby [Member] USD ($) | Jun. 30, 2013 Inland Empire Energy Center [Member] Y MW | Jun. 30, 2013 Inland Empire Energy Center [Member] Minimum [Member] Y | Jun. 30, 2013 Inland Empire Energy Center [Member] Maximum [Member] Y
Variable Interest Entity [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power generation capacity | 9,027 |  | 9,027 |  | 8,255 |  |  |  |  | 1,038 | 50 |  | 50 |  | 775 |  |
Variable Interest Entity, Financial or Other Support, Amount | $ 0 | $ 0 | $ 0 | $ 0 |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  |  |  |  | 50.00% | 50.00% |  | 50.00% |  |  |  |
Equity Method Investment, Summarized Financial Information, Debt | 412,000,000 |  | 412,000,000 |  | 448,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Prorata Share of Equity Method Investment, Summarized Financial Information, Debt | 206,000,000 |  | 206,000,000 |  | 224,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Summarized Financial Information, Term Loan Period |  |  |  |  |  |  |  |  |  | 18 years |  |  |  |  |  |  |
Equity Method Investment, Summarized Financial Information, Term Loan |  |  |  |  |  |  |  |  |  | 648,000,000 |  |  |  |  |  |  |
Distribution from equity method investee |  |  |  |  |  | $ 7,000,000 | $ 9,000,000 | $ 7,000,000 | $ 9,000,000 |  | $ 9,000,000 | $ 7,000,000 | $ 9,000,000 | $ 7,000,000 |  |  |
Call Option Exercise Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,017 | 2,024
Put Option Exercise Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,025 |  |

X
- Definition Call Option Exercise Period + References No definition available. + Details
Name: | cpn_CallOptionExercisePeriod
Namespace Prefix: | cpn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Distribution from equity method investee + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Equity Method Investment, Summarized Financial Information, Debt + References No definition available. + Details
Name: | cpn_EquityMethodInvestmentSummarizedFinancialInformationDebt
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Equity Method Investment, Summarized Financial Information, Term Loan + References No definition available. + Details
Name: | cpn_EquityMethodInvestmentSummarizedFinancialInformationTermLoan
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Equity Method Investment, Summarized Financial Information, Term Loan Period + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Power generation capacity + References No definition available. + Details
Name: | cpn_PowerGenerationCapacity
Namespace Prefix: | cpn_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Prorata Share of Equity Method Investment, Summarized Financial Information, Debt + References No definition available. + Details
Name: | cpn_ProrataShareOfEquityMethodInvestmentSummarizedFinancialInformationDebt
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Put Option Exercise Period + References No definition available. + Details
Name: | cpn_PutOptionExercisePeriod
Namespace Prefix: | cpn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 + Details
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Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of financial or other support the reporting entity has provided (explicitly or implicitly) to the Variable Interest Entity (VIE) that it was not previously contractually required to provide or that the reporting entity intends to provide, including, for example, situations in which the reporting entity assisted the VIE in obtaining another type of support. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=28200181&loc=SL6759159-111685 + Details
Name: | us-gaap_VariableInterestEntityFinancialOrOtherSupportAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration