v2.4.0.8

Debt (Fair Value of Debt) (Details) (USD $) In Millions, unless otherwise specified | Jun. 30, 2014 | Dec. 31, 2013
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Notes Payable, Fair Value Disclosure | $ 5,441 |  | $ 5,317 |
Loans Payable, Fair Value Disclosure | 2,822 |  | 2,845 |
Notes Payable, Other Payables, Disclosure | 1,736 | [1] | 1,772 | [1]
Subsidiaries Term Loan | 1,586 |  | 1,179 |
Debt Excluding Capital Leases | 11,585 |  | 11,113 |
Reported Value Measurement [Member] |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |
Notes Payable, Fair Value Disclosure | 4,990 |  | 4,989 |
Loans Payable, Fair Value Disclosure | 2,814 |  | 2,828 |
Notes Payable, Other Payables, Disclosure | 1,728 | [1] | 1,766 | [1]
Subsidiaries Term Loan | 1,603 |  | 1,191 |
Debt Excluding Capital Leases | $ 11,135 |  | $ 10,774 |
[1] | Excludes a lease that is accounted for as a failed sale-leaseback transaction under U.S. GAAP.

X
- Definition Debt Excluding Capital Leases + References No definition available. + Details
Name: | cpn_DebtExcludingCapitalLeases
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Notes Payable, Other Payables, Disclosure + References No definition available. + Details
Name: | cpn_NotesPayableOtherPayablesDisclosure
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Subsidiaries Term Loan + References No definition available. + Details
Name: | cpn_SubsidiariesTermLoan
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates. + References No definition available. + Details
Name: | us-gaap_LoansPayableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of notes payable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 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 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesPayableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant