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Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
dth
GWh
Dec. 31, 2013
GWh
dth
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours) 25,370duk_ElectricityEnergyGigawattHours 71,466duk_ElectricityEnergyGigawattHours
Natural gas (decatherms) 676,000,000duk_NaturalGasDecatherms 636,000,000duk_NaturalGasDecatherms
Interest Rate Contracts [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 1,027invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember		 832invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
Interest Rate Contracts [Member] | Nondesignated [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 277invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember		 34invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Interest Rate Contracts [Member] | Cash Flow Hedging [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 750invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember		 798invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
Interest Rate Contracts [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Cash Flow Hedging [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 541invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis
= us-gaap_VariableInterestEntityPrimaryBeneficiaryMember		 584invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_CashFlowHedgingMember
/ us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis
= us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Duke Energy Carolinas [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours)   1,205duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Natural gas (decatherms) 35,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		  
Progress Energy [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours)   925duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Natural gas (decatherms) 328,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 363,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Duke Energy Progress [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours)   925duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Natural gas (decatherms) 116,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		 141,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Duke Energy Florida [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Natural gas (decatherms) 212,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		 222,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Duke Energy Florida [Member] | Interest Rate Contracts [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 250invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Duke Energy Florida [Member] | Interest Rate Contracts [Member] | Nondesignated [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 250invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Duke Energy Ohio [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours) 19,141duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 69,362duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Natural gas (decatherms) 313,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 274,000,000duk_NaturalGasDecatherms
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 27invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 27invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Duke Energy Ohio [Member] | Interest Rate Contracts [Member] | Nondesignated [Member]    
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]    
Derivative, Notional Amount 27invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 27invest_DerivativeNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_InterestRateContractMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Duke Energy Indiana [Member]    
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]    
Electricity-energy (Gigawatt-hours)   203duk_ElectricityEnergyGigawattHours
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember