v2.4.1.9

Debt Debt (First Lien Notes) (Details) (USD $)
In Millions, unless otherwise specified

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

First Lien Notes 2019 [Member]

Debt Instrument [Line Items]

Long-term Debt

$ 0us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2019Member

^[1]

$ 320us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2019Member

^[1]

Debt Instrument, Interest Rate, Effective Percentage

0.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2019Member

^[2]

8.20%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2019Member

^[2]

First Lien Notes 2020 [Member]

Debt Instrument [Line Items]

Long-term Debt

0us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2020Member

^[1]

875us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2020Member

^[1]

Debt Instrument, Interest Rate, Effective Percentage

0.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2020Member

^[2]

8.20%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2020Member

^[2]

First Lien Notes 2021 [Member]

Debt Instrument [Line Items]

Long-term Debt

0us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2021Member

^[1]

1,600us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2021Member

^[1]

Debt Instrument, Interest Rate, Effective Percentage

0.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2021Member

^[2]

7.70%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2021Member

^[2]

2022 First Lien Notes [Member]

Debt Instrument [Line Items]

Long-term Debt

745us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2022FirstLienNotesMember

744us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2022FirstLienNotesMember

Debt Instrument, Interest Rate, Effective Percentage

6.30%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2022FirstLienNotesMember

^[2]

6.20%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2022FirstLienNotesMember

^[2]

First Lien Notes 2023 [Member]

Debt Instrument [Line Items]

Long-term Debt

840us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2023Member

^[3]

960us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2023Member

^[3]

Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed

10.00%us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2023Member

Debt Instrument, Interest Rate, Effective Percentage

8.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2023Member

^[2]

8.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_FirstLienNotes2023Member

^[2]

2024 First Lien Notes [Member]

Debt Instrument [Line Items]

Long-term Debt

490us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2024FirstLienNotesMember

490us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2024FirstLienNotesMember

Debt Instrument, Interest Rate, Effective Percentage

6.00%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2024FirstLienNotesMember

^[2]

5.90%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_LongtermDebtTypeAxis
= cpn_A2024FirstLienNotesMember

^[2]

Corporate Debt Securities [Member]

Debt Instrument [Line Items]

Long-term Debt

$ 2,075us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember

$ 4,989us-gaap_LongTermDebt
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CorporateDebtSecuritiesMember

[1]	The 2019 First Lien Notes, 2020 First Lien Notes and 2021 First Lien Notes were repaid during the third quarter of 2014 with the proceeds from the issuance of our Senior Unsecured Notes, together with cash on hand, which are described in further detail below.
[2]	Our weighted average interest rate calculation includes the amortization of deferred financing costs and debt discount.
[3]	In December 2014, we used cash on hand to redeem 10% of the original aggregate principal amount of our 2023 First Lien Notes, plus accrued and unpaid interest. On February 3, 2015, we additionally repurchased approximately $150 million of our 2023 First Lien Notes with the proceeds from our 2024 Senior Unsecured Notes, which is described in further detail below.

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7



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 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

-Article 5



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_A2022FirstLienNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_A2024FirstLienNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_FirstLienNotes2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_FirstLienNotes2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_FirstLienNotes2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=cpn_FirstLienNotes2023Member
Namespace Prefix:
Data Type:	na
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Period Type:

X

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
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