v2.4.1.9
Debt (Capital Lease Obligations) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Minimum Lease Payments, Sale Leaseback Transactions, Fiscal Year Maturity [Abstract]  
Minimum Lease Payments, Sale Leaseback Transactions, within One Year $ 25us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsWithinOneYear [1]
Minimum Lease Payments, Sale Leaseback Transactions, within Two Years 25us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsWithinTwoYears [1]
Minimum Lease Payments, Sale Leaseback Transactions, within Three Years 17us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsWithinThreeYears [1]
Minimum Lease Payments, Sale Leaseback Transactions, within Four Years 21us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsWithinFourYears [1]
Minimum Lease Payments, Sale Leaseback Transactions, within Five Years 21us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsWithinFiveYears [1]
Minimum Lease Payments, Sale Leaseback Transactions, Thereafter 85us-gaap_MinimumLeasePaymentsSaleLeasebackTransactionsThereafter [1]
Minimum Lease Payments, Sale Leaseback Transactions 194us-gaap_MinimumLeasePaymentsSaleLeasebackTransactions [1]
Interest Portion of Minimum Lease Payments, Sale Leaseback Transactions 72us-gaap_InterestPortionOfMinimumLeasePaymentsSaleLeasebackTransactions [1]
Present Value of Future Minimum Lease Payments, Sale Leaseback Transactions 122us-gaap_PresentValueOfFutureMinimumLeasePaymentsSaleLeasebackTransactions [1]
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]  
Capital Leases, Future Minimum Payments Due, Current 47us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent
Capital Leases, Future Minimum Payments Due in Two Years 41us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears
Capital Leases, Future Minimum Payments Due in Three Years 39us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears
Capital Leases, Future Minimum Payments Due in Four Years 38us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears
Capital Leases, Future Minimum Payments Due in Five Years 20us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears
Capital Leases, Future Minimum Payments Due Thereafter 151us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter
Capital Leases, Future Minimum Payments Due 336us-gaap_CapitalLeasesFutureMinimumPaymentsDue
Capital Leases, Future Minimum Payments, Interest Included in Payments 134us-gaap_CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments 202us-gaap_CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments
Total Leases Future Minimum Payments [Abstract]  
Total Leases, Future Minimum Payments Due, Current 72cpn_TotalLeasesFutureMinimumPaymentsDueCurrent
Total Leases, Future Minimum Payments Due in Two Years 66cpn_TotalLeasesFutureMinimumPaymentsDueInTwoYears
Total Leases, Future Minimum Payments Due in Three Years 56cpn_TotalLeasesFutureMinimumPaymentsDueInThreeYears
Total Leases, Future Minimum Payments Due in Four Years 59cpn_TotalLeasesFutureMinimumPaymentsDueInFourYears
Total Leases, Future Minimum Payments Due in Five Years 41cpn_TotalLeasesFutureMinimumPaymentsDueInFiveYears
Total Leases, Future Minimum Payments Due Thereafter 236cpn_TotalLeasesFutureMinimumPaymentsDueThereafter
Total Leases, Future Minimum Payments Due 530cpn_TotalLeasesFutureMinimumPaymentsDue
Total Leases, Future Minimum Payments, Interest Included in Payments 206cpn_TotalLeasesFutureMinimumPaymentsInterestIncludedInPayments
Total Leases, Future Minimum Payments, Present Value of Net Minimum Payments $ 324cpn_TotalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments
[1] Amounts are accounted for as financing transactions under U.S. GAAP and are included in our project financing, notes payable and other amounts above.