v3.8.0.1

Derivative Instruments (Detail 3) (Details) - USD ($) $ in Millions | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative assets, current | [1],[2] | $ 206 |  | $ 221 |
Derivative Asset, Noncurrent | [1],[2] | 284 |  | 300 |
Long-term derivative liabilities | [1],[2] | (103) |  | (149) |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 192 |  | 162 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 82 |  | 72 |
Derivative Liability, Current | [1],[2] | (113) |  | (138) |
Derivative Liability | [2] | (216) |  | (287) |
Derivative, Collateral, Right to Reclaim Cash |  | 115 |  | 262 |
Derivative, Fair Value, Net | [2] | 274 |  | 234 |
Derivative Asset | [2] | 490 |  | 521 |
Derivative Financial Instruments, Assets [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 1,319 |  | 2,268 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (829) |  | (1,747) |
Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative assets, current | [2] | 0 |  | 0 |
Derivative Asset, Noncurrent | [2] | 0 |  | 0 |
Long-term derivative liabilities | [2] | 0 |  | 0 |
Derivative Liability, Current | [2] | 0 |  | 0 |
Derivative Liability |  | (656) |  | (1,570) |
Derivative Asset |  | 605 |  | 1,542 |
Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative assets, current | [2] | 205 |  | 220 |
Derivative Asset, Noncurrent | [2] | 274 |  | 272 |
Long-term derivative liabilities | [2] | (85) |  | (119) |
Derivative Liability, Current | [2] | (88) |  | (110) |
Derivative Liability | [3] | (419) |  | (478) |
Derivative Asset | [3] | 694 |  | 697 |
Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative assets, current | [2] | 1 |  | 1 |
Derivative Asset, Noncurrent | [2] | 10 |  | 28 |
Long-term derivative liabilities | [2] | (18) |  | (30) |
Derivative Liability, Current | [2] | (25) |  | (28) |
Derivative Liability |  | (52) |  | (58) |
Derivative Asset |  | 20 |  | 29 |
Fair Value, Inputs, Level 3 [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Margin/Cash (Received) Posted Subject to Master Netting Arrangement |  | 14 |  | 17 |
Fair Value, Inputs, Level 3 [Member] | Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability |  | 0 |  | 0 |
Derivative Asset |  | 0 |  | 0 |
Fair Value, Inputs, Level 3 [Member] | Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability | [3] | (64) |  | (67) |
Derivative Asset | [3] | 332 |  | 466 |
Fair Value, Inputs, Level 3 [Member] | Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability |  | 0 |  | 0 |
Derivative Asset |  | 0 |  | 0 |
Derivative Assets, Current [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 812 | [4] | 1,725 | [1]
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (606) | [4] | (1,504) | [1]
Derivative Assets, Current [Member] | Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 472 |  | 1,344 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (472) |  | (1,344) |
Derivative Assets, Current [Member] | Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 338 |  | 380 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (133) |  | (160) |
Derivative Assets, Current [Member] | Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 2 |  | 1 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (1) |  | 0 |
Derivative Assets, Non-current [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 507 | [4] | 543 | [1]
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (223) | [4] | (243) | [1]
Derivative Assets, Non-current [Member] | Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 133 |  | 198 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (133) |  | (198) |
Derivative Assets, Non-current [Member] | Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 356 |  | 317 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (82) |  | (45) |
Derivative Assets, Non-current [Member] | Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement |  | 18 |  | 28 |
Derivative Asset, Collateral, Obligation to Return Cash, Offset |  | (8) |  | 0 |
Derivative Liabilities, Current [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 758 | [4] | 1,630 | [1]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 645 | [4] | 1,492 | [1]
Derivative Liabilities, Current [Member] | Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 496 |  | 1,327 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 496 |  | 1,327 |
Derivative Liabilities, Current [Member] | Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 236 |  | 275 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 148 |  | 165 |
Derivative Liabilities, Current [Member] | Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 26 |  | 28 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 1 |  | 0 |
Derivative Liabilities, Non-current [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 369 | [4] | 476 | [1]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 266 | [4] | 327 | [1]
Derivative Liabilities, Non-current [Member] | Future [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 160 |  | 243 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 160 |  | 243 |
Derivative Liabilities, Non-current [Member] | Forward Contracts [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 183 |  | 203 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 98 |  | 84 |
Derivative Liabilities, Non-current [Member] | Interest Rate Hedging Instruments |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 26 |  | 30 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | 8 |  | 0 |
Derivative Financial Instruments, Liabilities [Member] |  |  |  |  |
Derivative Instruments Subject to Master Netting Arrangement [Line Items] |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement |  | 1,127 |  | 2,106 |
Derivative Liability, Collateral, Right to Reclaim Cash, Offset |  | $ 911 |  | $ 1,819 |
[1] | At December 31, 2016, current and long-term derivative assets are shown net of collateral of $(29) million and $(3) million, respectively, and current and long-term derivative liabilities are shown net of collateral of $19 million and $85 million, respectively.
[2] | At September 30, 2017 and December 31, 2016, we had $115 million and $262 million of collateral under master netting arrangements that were not offset against our derivative instruments on the Consolidated Condensed Balance Sheets.
[3] | Includes OTC swaps and options and retail contracts.
[4] | At September 30, 2017, current and long-term derivative assets are shown net of collateral of $(4) million and $(8) million, respectively, and current and long-term derivative liabilities are shown net of collateral of $43 million and $51 million, respectively.

X
- Definition Derivative, Collateral, Right to Reclaim Cash, Net + References No definition available. + Details
Name: | cpn_DerivativeCollateralRightToReclaimCashNet
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition [Line Items] for Derivative Instruments Subject to Master Netting Arrangement [Table] + References No definition available. + Details
Name: | cpn_DerivativeInstrumentsSubjectToMasterNettingArrangementLineItems
Namespace Prefix: | cpn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssetCollateralObligationToReturnCashOffset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 + Details
Name: | us-gaap_DerivativeAssetsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
Name: | us-gaap_DerivativeAssetsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226016-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41678-113959 + Details
Name: | us-gaap_DerivativeCollateralRightToReclaimCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226008-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
Name: | us-gaap_DerivativeLiabilitiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611 + Details
Name: | us-gaap_DerivativeLiabilitiesNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 + Details
Name: | us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_DerivativeFinancialInstrumentsAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_FutureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForwardContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=cpn_DerivativeAssetsCurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=cpn_DerivativeAssetsNoncurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=cpn_DerivativeLiabilitiesCurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=cpn_DerivativeLiabilitiesNoncurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |