v2.4.1.9

Debt CCFC Term Loans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Incremental CCFC Term Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 425us-gaap_DebtInstrumentFaceAmount / us-gaap_LongtermDebtTypeAxis = cpn_IncrementalCCFCTermLoansMember
Long Term Debt net of Original Issuance Disount	98.75%cpn_LongTermDebtnetofOriginalIssuanceDisount / us-gaap_LongtermDebtTypeAxis = cpn_IncrementalCCFCTermLoansMember
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt	1,596us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember		1,191us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember
Debt Instrument, Interest Rate, Effective Percentage	3.40%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember	[1]	3.30%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember	[1]
Term loan interest rate spread option Federal Funds effective rate	0.50%cpn_TermloaninterestratespreadoptionFederalFundseffectiverate / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum	0.75%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember
Long Term Debt net of Original Issuance Disount	99.75%cpn_LongTermDebtnetofOriginalIssuanceDisount / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember
Percentage of the principal amount of the Term Loan to be paid quarterly	0.25%cpn_PercentageoftheprincipalamountoftheTermLoantobepaidquarterly / us-gaap_LongtermDebtTypeAxis = us-gaap_SecuredDebtMember
CCFC Term Loan B-1 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			900us-gaap_DebtInstrumentFaceAmount / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB1Member
Term Loan Period	7 years
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	2.25%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB1Member
Term loan interest rate spread option Prime Rate	1.25%cpn_TermloaninterestratespreadoptionPrimeRate / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB1Member
CCFC Term Loan B-2 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 300us-gaap_DebtInstrumentFaceAmount / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB2Member
Term Loan Period	8 years 6 months
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum	2.50%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB2Member
Term loan interest rate spread option Prime Rate	1.50%cpn_TermloaninterestratespreadoptionPrimeRate / us-gaap_LongtermDebtTypeAxis = cpn_CCFCTermLoanB2Member
[1] Our weighted average interest rate calculation includes the amortization of deferred financing costs and debt discount.

X

- Definition

Long Term Debt net of Original Issuance Disount

+ References

No definition available.

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X

- Definition

Percentage of the principal amount of the Term Loan to be paid quarterly

+ References

No definition available.

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X

- Definition

Term loan interest rate spread option Federal Funds effective rate

+ References

No definition available.

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- Definition

Term loan interest rate spread option Prime Rate

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- Definition

Term Loan Period

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No definition available.

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X

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Maximum contractual interest rate for funds borrowed, under the debt agreement.

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-Name Regulation S-X (SX)

-Number 210

-Section 02

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- Definition

Minimum contractual interest rate for funds borrowed, under the debt agreement.

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-Number 210

-Section 02

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X

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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