XML 93 R141.htm IDEA: XBRL DOCUMENT v2.4.1.9
Employee Benefit Plans (Amounts Recognized in Accumulated Other Comprehensive Income and Regulatory Assets and Liabilities) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense)   $ 17us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax $ 9us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
Net amount recognized in accumulated other comprehensive (income) loss (4)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax [1] (38)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax [1] (19)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax [1]
Progress Energy [Member]      
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss (9)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (9)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 2us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Duke Energy Ohio [Member]      
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss   (1)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 (27)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Qualified Pension Plans [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 112us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 (788)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) (10)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 18us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Actuarial (gains) losses arising during the year 29us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 (33)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Prior year service cost (credit) arising during the year   (1)us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Amortization of prior year actuarial gains (losses) (9)duk_OtherComprehensiveIncomeDefinedBenefitPlansAmortizationOfPriorYearActuarialGainLossBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 (15)duk_OtherComprehensiveIncomeDefinedBenefitPlansAmortizationOfPriorYearActuarialGainLossBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Reclassification of actuarial gains (losses) to regulatory assets (1)duk_OtherComprehensiveIncomeDefinedBenefitPlansReclassificationOfActuarialLossesToRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 3duk_OtherComprehensiveIncomeDefinedBenefitPlansReclassificationOfActuarialLossesToRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Net amount recognized in accumulated other comprehensive (income) loss 9us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		 (28)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember		  
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 30us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		 (205)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		  
Qualified Pension Plans [Member] | Progress Energy [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) (73)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (253)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) (2)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		    
Actuarial (gains) losses arising during the year   (2)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Amortization of prior year actuarial gains (losses)   (3)duk_OtherComprehensiveIncomeDefinedBenefitPlansAmortizationOfPriorYearActuarialGainLossBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Net amount recognized in accumulated other comprehensive (income) loss (2)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (5)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Qualified Pension Plans [Member] | Duke Energy Progress [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) (17)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		 (109)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		  
Qualified Pension Plans [Member] | Duke Energy Florida [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 11us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		 (146)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 17us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 (96)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		  
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 4us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		 (99)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Net amount recognized in accumulated other comprehensive (income) loss 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		 0us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		  
Non Qualified Pension Plans [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 44us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		 (14)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		  
Regulatory liabilities, net increase (decrease) (7)us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		 5us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) 4us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		    
Actuarial (gains) losses arising during the year (9)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		 2us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		  
Prior year service cost (credit) arising during the year   (1)us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		  
Net amount recognized in accumulated other comprehensive (income) loss (5)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		 1us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember		  
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 1us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		 1us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		  
Non Qualified Pension Plans [Member] | Progress Energy [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 14us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (16)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) 5us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 1us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Actuarial (gains) losses arising during the year (11)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (5)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Net amount recognized in accumulated other comprehensive (income) loss (6)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (4)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 4us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		 (4)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		  
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 19us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		 (3)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Non Qualified Pension Plans [Member] | Duke Energy Ohio [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 1us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		    
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 2us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		 (2)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		  
Other Post-Retirement Benefit Plans [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 162us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 (683)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Regulatory liabilities, net increase (decrease) 249us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 30us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) 1us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 2us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Actuarial (gains) losses arising during the year 1us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 (4)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Prior year service cost (credit) arising during the year (6)us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 (3)us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Amortization of prior year actuarial gains (losses)   1duk_OtherComprehensiveIncomeDefinedBenefitPlansAmortizationOfPriorYearActuarialGainLossBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Amortization of prior year prior service credit 2us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		    
Net amount recognized in accumulated other comprehensive (income) loss (2)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		 (4)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember		  
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 34us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		 (51)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		  
Regulatory liabilities, net increase (decrease) 76us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember		    
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 129us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		 (634)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		  
Regulatory liabilities, net increase (decrease) 122us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		    
Amounts Recognized in Accumulated Other Comprehensive Loss (Income) [Abstract]      
Deferred income tax benefit (expense) 1us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		    
Actuarial (gains) losses arising during the year (2)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		    
Net amount recognized in accumulated other comprehensive (income) loss (1)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember		    
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) 97us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		 (388)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		  
Regulatory liabilities, net increase (decrease) 61us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember		    
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) (4)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		 (166)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		  
Regulatory liabilities, net increase (decrease) 61us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember		    
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory liabilities, net increase (decrease) (2)us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		 3us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember		  
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]      
Amounts Recognized in Regulatory Assets and Liabilities [Abstract]      
Regulatory assets, net increase (decrease) (7)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		 (6)us-gaap_IncreaseDecreaseInOtherRegulatoryAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		  
Regulatory liabilities, net increase (decrease) $ 14us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		 $ 9us-gaap_IncreaseDecreaseInRegulatoryLiabilities
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember		  
[1] Net of insignificant tax expense in 2014, $17 million tax expense in 2013 and $9 million tax expense in 2012. See Note 21 for additional information.