Employee Benefit Plans (Contributions to Defined Benefit Pension Plans) (Details) (Qualified Pension Plans [Member], USD $) In Millions, unless otherwise specified
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12 Months Ended |
Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Defined Benefit Plan Disclosure [Line Items] |
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Employer contributions |
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$ 250us-gaap_DefinedBenefitPlanContributionsByEmployer |
$ 304us-gaap_DefinedBenefitPlanContributionsByEmployer |
Anticipated contribution |
302us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear |
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Duke Energy Carolinas [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Anticipated contribution |
91us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyCarolinasMember |
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Progress Energy [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Employer contributions |
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250us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_ProgressEnergyMember |
346us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_ProgressEnergyMember |
Anticipated contribution |
83us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_ProgressEnergyMember |
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Duke Energy Progress [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Employer contributions |
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63us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyProgressMember |
141us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyProgressMember |
Anticipated contribution |
42us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyProgressMember |
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Duke Energy Florida [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Employer contributions |
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133us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyFloridaMember |
128us-gaap_DefinedBenefitPlanContributionsByEmployer / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyFloridaMember |
Anticipated contribution |
40us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyFloridaMember |
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Duke Energy Ohio [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Anticipated contribution |
8us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyOhioMember |
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Duke Energy Indiana [Member] |
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Defined Benefit Plan Disclosure [Line Items] |
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Anticipated contribution |
$ 19us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear / us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis = us-gaap_PensionPlansDefinedBenefitMember / dei_LegalEntityAxis = duk_DukeEnergyIndianaMember |
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