v2.4.0.8

Shareholder Transaction (Details) (USD $) | Sep. 30, 2014
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Shareholder Transaction [Abstract] |
Shareholder Ownership Percentage | 10.00%
Common Stock Purchased from Shareholder | 13,213,372
Purchase Price of Common Stock Purchased from Shareholder | $ 311,464,283

X
- Definition Common Stock Purchased from Shareholder + References No definition available. + Details
Name: | cpn_CommonStockPurchasedfromShareholder
Namespace Prefix: | cpn_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Purchase Price of Common Stock Purchased from Shareholder + References No definition available. + Details
Name: | cpn_PurchasePriceofCommonStockPurchasedfromShareholder
Namespace Prefix: | cpn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Shareholder Ownership Percentage + References No definition available. + Details
Name: | cpn_ShareholderOwnershipPercentage
Namespace Prefix: | cpn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | cpn_ShareholderTransactionAbstract
Namespace Prefix: | cpn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration