v2.4.0.8

Debt (Fair Value of Debt) (Details) (USD $) In Millions, unless otherwise specified | Jun. 30, 2013 | Dec. 31, 2012
--- | --- | ---
Portion at Fair Value, Fair Value Disclosure [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Notes Payable, Fair Value Disclosure | $ 5,621 |  | $ 5,863 |
Subsidiaries Notes Disclosure | 0 |  | 1,075 |
Notes Payable, Other Payables, Disclosure | 1,670 | [1] | 1,599 | [1]
Subsidiaries Term Loan | 1,180 |  | 0 |
Loans Payable, Fair Value Disclosure | 2,452 |  | 2,489 |
Debt Excluding Capital Leases | 10,923 |  | 11,026 |
Carrying (Reported) Amount, Fair Value Disclosure [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Notes Payable, Fair Value Disclosure | 5,304 |  | 5,303 |
Subsidiaries Notes Disclosure | 0 |  | 978 |
Notes Payable, Other Payables, Disclosure | 1,723 | [1] | 1,629 | [1]
Subsidiaries Term Loan | 1,197 |  | 0 |
Loans Payable, Fair Value Disclosure | 2,450 |  | 2,463 |
Debt Excluding Capital Leases | $ 10,674 |  | $ 10,373 |
[1] | Excludes a lease that is accounted for as a failed sale-leaseback transaction under U.S. GAAP.

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- Definition Debt Excluding Capital Leases + References No definition available. + Details
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Namespace Prefix: | cpn_
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- Definition Notes Payable, Other Payables, Disclosure + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
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- Definition Subsidiaries Notes Disclosure + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Subsidiaries Term Loan + References No definition available. + Details
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Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Details
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- Definition Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
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Period Type: | instant

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- Definition Fair value portion of notes payable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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Namespace Prefix: | us-gaap_
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