v2.4.1.9

Debt (First Lien Notes) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt	$ 11,619us-gaap_LongTermDebt		$ 11,122us-gaap_LongTermDebt
2022 First Lien Notes [Member]
Debt Instrument [Line Items]
Long-term Debt	745us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = cpn_A2022FirstLienNotesMember		745us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = cpn_A2022FirstLienNotesMember
First Lien Notes 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt	693us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = cpn_FirstLienNotes2023Member	[1]	840us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = cpn_FirstLienNotes2023Member	[1]
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
Corporate Debt Securities [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 1,928us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember		$ 2,075us-gaap_LongTermDebt / us-gaap_LongtermDebtTypeAxis = us-gaap_CorporateDebtSecuritiesMember
[1] On February 3, 2015, we repurchased approximately $147 million of our 2023 First Lien Notes with the proceeds from our 2024 Senior Unsecured Notes, which is described in further detail above.

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- 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

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