v2.3.0.15

Derivative Instruments (Details 3) (USD $) In Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010
Realized and unrealized gains (losses) [Line Items] |  |  |  |
Realized gain (loss) | $ 21 | $ 27 | $ (33) | $ 67
Unrealized gain (loss) | 35 | 35 | 42 | (97)
Components of mark-to-market activities for realized/unrealized gains (losses) [Abstract] |  |  |  |
Power contracts included in operating revenues | 18 | 22 | 9 | 34
Natural gas contracts included in fuel and purchased energy expense | 39 | 150 | 61 | 271
Interest rate swaps included in interest expense | 2 | (26) | 4 | (54)
Gain (Loss) on interest rate derivatives, net | (3) | (84) | (149) | (87)
Total mark-to-market activity | 56 | 62 | (75) | 164
Interest Rate Swaps |  |  |  |
Realized and unrealized gains (losses) [Line Items] |  |  |  |
Realized gain (loss) | (44) | (14) | (150) | (26)
Unrealized gain (loss) | 43 | (96) | 5 | (115)
Commodity instruments |  |  |  |
Realized and unrealized gains (losses) [Line Items] |  |  |  |
Realized gain (loss) | 65 | 41 | 117 | 93
Unrealized gain (loss) | $ (8) | $ 131 | $ (47) | $ 212

X
- Definition Interest rate swaps included in interest expense + Details
Name: | cpn_InterestRateSwapsIncludedInInterestExpense
Namespace Prefix: | cpn
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Natural gas contracts included in fuel and purchased energy expense + Details
Name: | cpn_NaturalGasContractsIncludedInFuelAndPurchasedEnergyExpense
Namespace Prefix: | cpn
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Power contracts included in operating revenues + Details
Name: | cpn_PowerContractsIncludedInOperatingRevenues
Namespace Prefix: | cpn
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Realized gain (loss) on derivatives + Details
Name: | cpn_RealizedGainLossOnDerivatives
Namespace Prefix: | cpn
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959 + Details
Name: | us-gaap_GainLossOnDerivativeInstrumentsNetPretax
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 -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 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959 + Details
Name: | us-gaap_GainLossOnInterestRateDerivativeInstrumentsNotDesignatedAsHedgingInstruments
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + Details
Name: | us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix: | us-gaap
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 -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 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 + Details
Name: | us-gaap_UnrealizedGainLossOnDerivatives
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration