v2.4.0.6

Acquisitions, Divestitures and Discontinued Operations (Acquisition of Broad River and South Point Leases) (Details) (USD $) In Millions, unless otherwise specified | Dec. 08, 2010
--- | ---
Business Acquisition [Line Items] |
Debt Extinguishment Costs Due To Acquisition | $ 30
Impairment Loss Due To Acquisition | 95
Business Acquisition, Preexisting Relationship, Gain (Loss) Recognized | $ 125

X
- Definition Debt Extinguishment Costs Due To Acquisition + References No definition available. + Details
Name: | cpn_DebtExtinguishmentCostsDueToAcquisition
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Impairment Loss Due To Acquisition + References No definition available. + Details
Name: | cpn_ImpairmentLossDueToAcquisition
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Income (expense) and gain (loss) recognized from the settlement of a preexisting relationship between the acquirer and the acquiree. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 04-1 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=7659399&loc=d3e1392-128463 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 57 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 68 -Subparagraph m(1-4) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_BusinessAcquisitionPreexistingRelationshipGainLossRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant