XML 122 R8.htm IDEA: XBRL DOCUMENT v2.4.1.9
Consolidated Statements of Cash Flows (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income $ 1,889us-gaap_ProfitLoss $ 2,676us-gaap_ProfitLoss $ 1,782us-gaap_ProfitLoss
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 3,507us-gaap_DepreciationDepletionAndAmortization 3,229us-gaap_DepreciationDepletionAndAmortization 2,652us-gaap_DepreciationDepletionAndAmortization
Equity component of AFUDC (135)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity (157)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity (300)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
Severance expense     92duk_SeveranceExpenseNetOfPayments
FERC mitigation costs (15)duk_MergerMitigation   117duk_MergerMitigation
Community support and charitable contributions   34duk_CommunitySupportAndCharitableContributionsAndOtherExpenses 92duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
(Gains) losses on sales of other assets (33)us-gaap_GainLossOnSaleOfOtherAssets (79)us-gaap_GainLossOnSaleOfOtherAssets (44)us-gaap_GainLossOnSaleOfOtherAssets
Impairment charges 915us-gaap_OtherAssetImpairmentCharges 400us-gaap_OtherAssetImpairmentCharges 586us-gaap_OtherAssetImpairmentCharges
Deferred income taxes 1,149us-gaap_DeferredIncomeTaxesAndTaxCredits 1,264us-gaap_DeferredIncomeTaxesAndTaxCredits 584us-gaap_DeferredIncomeTaxesAndTaxCredits
Equity in earnings of unconsolidated affiliates (130)us-gaap_IncomeLossFromEquityMethodInvestments (122)us-gaap_IncomeLossFromEquityMethodInvestments (148)us-gaap_IncomeLossFromEquityMethodInvestments
Voluntary opportunity cost deferral     (101)duk_VoluntaryOpportunityCostDeferral
Accrued pension and other post-retirement benefit costs 108us-gaap_PensionAndOtherPostretirementBenefitExpense 307us-gaap_PensionAndOtherPostretirementBenefitExpense 239us-gaap_PensionAndOtherPostretirementBenefitExpense
Contributions to qualified pension plans   (250)us-gaap_PensionContributions (304)us-gaap_PensionContributions
(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions 44us-gaap_UnrealizedGainLossOnDerivatives 1us-gaap_UnrealizedGainLossOnDerivatives 60us-gaap_UnrealizedGainLossOnDerivatives
Receivables 58us-gaap_IncreaseDecreaseInReceivables (281)us-gaap_IncreaseDecreaseInReceivables 39us-gaap_IncreaseDecreaseInReceivables
Inventory (269)us-gaap_IncreaseDecreaseInInventories (31)us-gaap_IncreaseDecreaseInInventories (258)us-gaap_IncreaseDecreaseInInventories
Other current assets (414)us-gaap_IncreaseDecreaseInOtherCurrentAssets (35)us-gaap_IncreaseDecreaseInOtherCurrentAssets 140us-gaap_IncreaseDecreaseInOtherCurrentAssets
Increase (decrease) in [Abstract]      
Accounts payable (30)us-gaap_IncreaseDecreaseInAccountsPayable 73us-gaap_IncreaseDecreaseInAccountsPayable 131us-gaap_IncreaseDecreaseInAccountsPayable
Taxes accrued (14)us-gaap_IncreaseDecreaseInAccruedTaxesPayable 77us-gaap_IncreaseDecreaseInAccruedTaxesPayable (142)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
Other current liabilities (201)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities 24us-gaap_IncreaseDecreaseInOtherCurrentLiabilities 295us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
Other assets 16us-gaap_IncreaseDecreaseInOtherOperatingAssets (384)us-gaap_IncreaseDecreaseInOtherOperatingAssets (129)us-gaap_IncreaseDecreaseInOtherOperatingAssets
Other liabilities 141us-gaap_IncreaseDecreaseInOtherOperatingLiabilities (364)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities (139)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
Net cash provided by (used in) operating activities 6,586us-gaap_NetCashProvidedByUsedInOperatingActivities 6,382us-gaap_NetCashProvidedByUsedInOperatingActivities 5,244us-gaap_NetCashProvidedByUsedInOperatingActivities
Net Income (Loss) Attributable to Parent 1,883us-gaap_NetIncomeLoss 2,665us-gaap_NetIncomeLoss 1,768us-gaap_NetIncomeLoss
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (5,384.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment (5,526.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment (5,501.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Investment expenditures (90)us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates (81)us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates (6)us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates
Acquisitions (54)us-gaap_PaymentsToAcquireBusinessesGross   (451)us-gaap_PaymentsToAcquireBusinessesGross
Cash acquired from the merger with Progress Energy     71us-gaap_CashAcquiredFromAcquisition
Purchases of available-for-sale securities (4,110)us-gaap_PaymentsToAcquireAvailableForSaleSecurities (6,142)us-gaap_PaymentsToAcquireAvailableForSaleSecurities (4,719)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
Proceeds from sales and maturities of available-for-sale securities 4,133us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities 6,315us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities 4,537us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
Net proceeds from the sales of equity investments and other assets, and sales of and collections on notes receivable 179us-gaap_ProceedsFromSaleOfProductiveAssets 277us-gaap_ProceedsFromSaleOfProductiveAssets 212us-gaap_ProceedsFromSaleOfProductiveAssets
Change in Restricted Cash 9us-gaap_IncreaseDecreaseInRestrictedCash 167us-gaap_IncreaseDecreaseInRestrictedCash (414)us-gaap_IncreaseDecreaseInRestrictedCash
Other (56)us-gaap_PaymentsForProceedsFromOtherInvestingActivities 12us-gaap_PaymentsForProceedsFromOtherInvestingActivities 74us-gaap_PaymentsForProceedsFromOtherInvestingActivities
Net cash (used in) provided by investing activities (5,373)us-gaap_NetCashProvidedByUsedInInvestingActivities (4,978)us-gaap_NetCashProvidedByUsedInInvestingActivities (6,197)us-gaap_NetCashProvidedByUsedInInvestingActivities
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt 2,914us-gaap_ProceedsFromIssuanceOfLongTermDebt 3,601us-gaap_ProceedsFromIssuanceOfLongTermDebt 4,170us-gaap_ProceedsFromIssuanceOfLongTermDebt
Proceeds from the issuance of common stock related to employee benefit plans 25us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans 9us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans 23us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans
Payments for the redemption of long-term debt (3,037)us-gaap_RepaymentsOfLongTermDebt (2,761)us-gaap_RepaymentsOfLongTermDebt (2,498)us-gaap_RepaymentsOfLongTermDebt
Payments for the redemption of preferred stock   (96)us-gaap_PaymentsForRepurchaseOfRedeemablePreferredStock  
Proceeds from issuance of short-term debt with original maturities greater than 90 days 1,066us-gaap_ProceedsFromShortTermDebtMaturingInMoreThanThreeMonths    
Payments for the redemption of short-term debt with original maturities greater than 90 days (564)us-gaap_RepaymentsOfShortTermDebtMaturingInMoreThanThreeMonths    
Notes payable and commercial paper 1,186us-gaap_ProceedsFromRepaymentsOfShortTermDebt 93us-gaap_ProceedsFromRepaymentsOfShortTermDebt 278us-gaap_ProceedsFromRepaymentsOfShortTermDebt
Distributions to noncontrolling interests (65)us-gaap_PaymentsOfDividendsMinorityInterest (15)us-gaap_PaymentsOfDividendsMinorityInterest (25)us-gaap_PaymentsOfDividendsMinorityInterest
Contributions from noncontrolling Interests   9us-gaap_ProceedsFromMinorityShareholders 76us-gaap_ProceedsFromMinorityShareholders
Dividends paid (2,234)us-gaap_PaymentsOfDividends (2,188)us-gaap_PaymentsOfDividends (1,752)us-gaap_PaymentsOfDividends
Other 31us-gaap_ProceedsFromPaymentsForOtherFinancingActivities 21us-gaap_ProceedsFromPaymentsForOtherFinancingActivities (5)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
Net cash provided by (used in) financing activities (678)us-gaap_NetCashProvidedByUsedInFinancingActivities (1,327)us-gaap_NetCashProvidedByUsedInFinancingActivities 267us-gaap_NetCashProvidedByUsedInFinancingActivities
Net increase (decrease) in cash and cash equivalents 535us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease 77us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease (686)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
Cash and cash equivalents at beginning of period 1,501us-gaap_CashAndCashEquivalentsAtCarryingValue 1,424us-gaap_CashAndCashEquivalentsAtCarryingValue 2,110us-gaap_CashAndCashEquivalentsAtCarryingValue
Cash and cash equivalents at end of period 2,036us-gaap_CashAndCashEquivalentsAtCarryingValue 1,501us-gaap_CashAndCashEquivalentsAtCarryingValue 1,424us-gaap_CashAndCashEquivalentsAtCarryingValue
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 1,659us-gaap_InterestPaidNet 1,665us-gaap_InterestPaidNet 1,032us-gaap_InterestPaidNet
Cash paid for (received from) income taxes 158us-gaap_IncomeTaxesPaidNet (202)us-gaap_IncomeTaxesPaidNet 72us-gaap_IncomeTaxesPaidNet
Merger with Progress Energy [Abstract]      
Fair value of assets acquired     48,944us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1
Liabilities assumed     30,873us-gaap_NoncashOrPartNoncashAcquisitionValueOfLiabilitiesAssumed1
Issuance of common stock     18,071us-gaap_StockIssued1
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 664us-gaap_CapitalExpendituresIncurredButNotYetPaid 594us-gaap_CapitalExpendituresIncurredButNotYetPaid 684us-gaap_CapitalExpendituresIncurredButNotYetPaid
Duke Energy Carolinas [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income 1,072us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
976us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
 
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 1,273us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
1,167us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
1,143us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Equity component of AFUDC (91)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(91)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(154)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
FERC mitigation costs 3duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
  46duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Community support and charitable contributions   14duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
56duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(Gains) losses on sales of other assets     (12)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Deferred income taxes 376us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
534us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
479us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Voluntary opportunity cost deferral     (101)duk_VoluntaryOpportunityCostDeferral
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Accrued pension and other post-retirement benefit costs 22us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
38us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
41us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions   (9)us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
 
Receivables 48us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(12)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
22us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Receivables from affiliated companies   (72)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Inventory (60)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(9)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(128)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other current assets (236)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
46us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Increase (decrease) in [Abstract]      
Accounts payable 10us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
58us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(51)us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Accounts payable to affiliated companies (7)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
33us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(28)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Taxes accrued (15)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
4us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(12)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other current liabilities (10)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(40)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
165us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other assets 17us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(102)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(117)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other liabilities (22)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(77)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(126)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Net cash provided by (used in) operating activities 2,380us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
2,411us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
2,133us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Net Income (Loss) Attributable to Parent 1,072us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
976us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
865us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (1,879.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1,695.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1,908.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Purchases of available-for-sale securities (2,064)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(2,405)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(2,481)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Proceeds from sales and maturities of available-for-sale securities 2,044us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
2,363us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
2,445us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Notes receivable from affiliated companies 72us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
160us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
541us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other (18)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(24)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(12)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Net cash (used in) provided by investing activities (1,845)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1,601)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1,415)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt   100us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
645us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Payments for the redemption of long-term debt (45)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(405)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(1,177)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Dividends or distributions to parent (500)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(499)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(450)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Other   (2)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(6)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Net cash provided by (used in) financing activities (545)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(806)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(988)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Net increase (decrease) in cash and cash equivalents (10)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
4us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(270)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Cash and cash equivalents at beginning of period 23us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
19us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
289us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Cash and cash equivalents at end of period 13us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
23us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
19us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 388us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
336us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
385us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Cash paid for (received from) income taxes 305us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(7)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
(38)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 194us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
199us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
194us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyCarolinasMember
Progress Energy [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income 874us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
675us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
407us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 1,313us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
1,041us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
897us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Equity component of AFUDC (26)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(50)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(106)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Severance expense     38duk_SeveranceExpenseNetOfPayments
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
FERC mitigation costs (18)duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
  71duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Community support and charitable contributions   20duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
36duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(Gains) losses on sales of other assets (6)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
2us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(16)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Impairment charges 2us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
380us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
146us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Deferred income taxes 1,014us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
616us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
263us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Amount to be refunded to customers     100duk_AmountToBeRefundedToCustomers
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Accrued pension and other post-retirement benefit costs 27us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
172us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
179us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Contributions to qualified pension plans   (250)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(346)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions 12us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
55us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
7us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Receivables (31)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(148)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
49us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Receivables from affiliated companies (56)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
11us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(15)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Inventory (101)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
17us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(71)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other current assets (934)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(156)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
2us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Increase (decrease) in [Abstract]      
Accounts payable 6us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(81)us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
175us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Accounts payable to affiliated companies 80us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
93us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
30us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Taxes accrued (20)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
22us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
25us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other current liabilities (144)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
61us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
81us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other assets (14)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(243)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(25)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other liabilities (12)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(115)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(87)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Net cash provided by (used in) operating activities 1,966us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
2,122us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
1,840us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Net Income (Loss) Attributable to Parent 869us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
672us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
400us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (1,940.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(2,490.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(2,366.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Purchases of available-for-sale securities (1,689)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(2,558)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(1,374)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Proceeds from sales and maturities of available-for-sale securities 1,652us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
2,513us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
1,325us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Notes receivable from affiliated companies (145)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(75)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
 
Change in Restricted Cash     24us-gaap_IncreaseDecreaseInRestrictedCash
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other (44)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
13us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
109us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Net cash (used in) provided by investing activities (2,166)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(2,597)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(2,282)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt 1,572us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
845us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
2,074us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Proceeds from the issuance of common stock related to employee benefit plans     6us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Payments for the redemption of long-term debt (931)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(1,196)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(962)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Payments for the redemption of preferred stock   (96)us-gaap_PaymentsForRepurchaseOfRedeemablePreferredStock
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
 
Proceeds from issuance of short-term debt with original maturities greater than 90 days     65us-gaap_ProceedsFromShortTermDebtMaturingInMoreThanThreeMonths
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Payments for the redemption of short-term debt with original maturities greater than 90 days     (65)us-gaap_RepaymentsOfShortTermDebtMaturingInMoreThanThreeMonths
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Notes payable and commercial paper     (671)us-gaap_ProceedsFromRepaymentsOfShortTermDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Notes payable to affiliated companies (378)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
758us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
455us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Distributions to noncontrolling interests (37)us-gaap_PaymentsOfDividendsMinorityInterest
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(3)us-gaap_PaymentsOfDividendsMinorityInterest
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(7)us-gaap_PaymentsOfDividendsMinorityInterest
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Dividends paid     (445)us-gaap_PaymentsOfDividends
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Other (42)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(6)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(7)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Net cash provided by (used in) financing activities 184us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
302us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
443us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Net increase (decrease) in cash and cash equivalents (16)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(173)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
1us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Cash and cash equivalents at beginning of period 58us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
231us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
230us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Cash and cash equivalents at end of period 42us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
58us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
231us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 664us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
678us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
784us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Cash paid for (received from) income taxes 141us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(167)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
(4)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 294us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
255us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
375us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Asset retirement obligation additions for spent nuclear fuel disposal related to the Progress Energy merger     837duk_AssetRetirementObligationAdditionsForSpentNuclearFuelDisposal
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Capital expenditures financed through capital leases     140us-gaap_CapitalLeaseObligationsIncurred
/ dei_LegalEntityAxis
= duk_ProgressEnergyMember
Duke Energy Progress [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income 467us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
500us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
272us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 761us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
685us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
676us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Equity component of AFUDC (25)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(42)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(69)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Severance expense     18duk_SeveranceExpenseNetOfPayments
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
FERC mitigation costs (18)duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
  71duk_MergerMitigation
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Community support and charitable contributions   20duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
36duk_CommunitySupportAndCharitableContributionsAndOtherExpenses
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(Gains) losses on sales of other assets (3)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Impairment charges   22us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
 
Deferred income taxes 455us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
368us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
164us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Accrued pension and other post-retirement benefit costs (7)us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
72us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
70us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Contributions to qualified pension plans   (63)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(141)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions 13us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(9)us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(25)us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Receivables 78us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(88)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
2us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Receivables from affiliated companies (8)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
3us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(4)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Inventory (65)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(26)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(58)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Other current assets (416)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(39)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(24)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Increase (decrease) in [Abstract]      
Accounts payable 27us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(18)us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
149us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Accounts payable to affiliated companies 17us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
27us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
47us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Taxes accrued 10us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
15us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(5)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Other current liabilities (68)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(86)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
23us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Other assets 48us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(74)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(28)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Other liabilities (21)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(78)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(6)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Net cash provided by (used in) operating activities 1,245us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
1,188us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
1,167us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (1,241.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1,567.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1,525.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Purchases of available-for-sale securities (499)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(901)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(582)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Proceeds from sales and maturities of available-for-sale securities 458us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
856us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
532us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Notes receivable from affiliated companies (237)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
   
Other (12)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
4us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
91us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Net cash (used in) provided by investing activities (1,531)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1,608)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(1,484)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt 1,347us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
845us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
988us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Payments for the redemption of long-term debt (379)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(451)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(502)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Payments for the redemption of preferred stock   (62)us-gaap_PaymentsForRepurchaseOfRedeemablePreferredStock
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
0us-gaap_PaymentsForRepurchaseOfRedeemablePreferredStock
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Notes payable and commercial paper     (188)us-gaap_ProceedsFromRepaymentsOfShortTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Notes payable to affiliated companies (462)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
98us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
333us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Dividends or distributions to parent (225)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
  (310)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Dividends paid on preferred stock     (3)us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Other (7)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(7)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(3)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Net cash provided by (used in) financing activities 274us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
423us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
315us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Net increase (decrease) in cash and cash equivalents (12)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
3us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(2)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Cash and cash equivalents at beginning of period 21us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
18us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
20us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Cash and cash equivalents at end of period 9us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
21us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
18us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 220us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
217us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
249us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Cash paid for (received from) income taxes 81us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
(94)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
19us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 194us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
166us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
232us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Asset retirement obligation additions for spent nuclear fuel disposal related to the Progress Energy merger     698duk_AssetRetirementObligationAdditionsForSpentNuclearFuelDisposal
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Capital expenditures financed through capital leases     140us-gaap_CapitalLeaseObligationsIncurred
/ dei_LegalEntityAxis
= duk_DukeEnergyProgressMember
Duke Energy Florida [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income 548us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
325us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
266us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 550us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
335us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
197us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Equity component of AFUDC   (8)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(37)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Severance expense     6duk_SeveranceExpenseNetOfPayments
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(Gains) losses on sales of other assets (1)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(1)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(2)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Impairment charges 2us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
358us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
146us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Deferred income taxes 400us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
368us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
142us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Amount to be refunded to customers     100duk_AmountToBeRefundedToCustomers
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Accrued pension and other post-retirement benefit costs 29us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
79us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
71us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Contributions to qualified pension plans   (133)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(128)us-gaap_PensionContributions
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions (9)us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
55us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
73us-gaap_UnrealizedGainLossOnDerivatives
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Receivables (33)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(44)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
37us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Receivables from affiliated companies (37)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
17us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(13)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Inventory (36)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
42us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(13)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other current assets (269)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(109)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
22us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Increase (decrease) in [Abstract]      
Accounts payable 18us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(22)us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
21us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Accounts payable to affiliated companies 32us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(6)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
30us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Taxes accrued (31)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
18us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
15us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other current liabilities (80)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
159us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
51us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other assets (59)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(154)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
8us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other liabilities (58)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(74)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(94)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Net cash provided by (used in) operating activities 966us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
1,205us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
898us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (699.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(915.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(809.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Purchases of available-for-sale securities (1,189)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(1,656)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(791)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Proceeds from sales and maturities of available-for-sale securities 1,195us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
1,658us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
791us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Notes receivable from affiliated companies   207us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(207)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other (31)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
  16us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Net cash (used in) provided by investing activities (724)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(706)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(1,000)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt 225us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
  642us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Payments for the redemption of long-term debt (252)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(435)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(10)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Payments for the redemption of preferred stock   (34)us-gaap_PaymentsForRepurchaseOfRedeemablePreferredStock
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
 
Proceeds from issuance of short-term debt with original maturities greater than 90 days     65us-gaap_ProceedsFromShortTermDebtMaturingInMoreThanThreeMonths
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Payments for the redemption of short-term debt with original maturities greater than 90 days     (65)us-gaap_RepaymentsOfShortTermDebtMaturingInMoreThanThreeMonths
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Notes payable and commercial paper     (233)us-gaap_ProceedsFromRepaymentsOfShortTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Notes payable to affiliated companies (97)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
181us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(8)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Dividends or distributions to parent (124)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(325)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(170)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Dividends paid on preferred stock     (2)us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Other (2)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(1)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(2)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Net cash provided by (used in) financing activities (250)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(614)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
217us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Net increase (decrease) in cash and cash equivalents (8)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(115)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
115us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Cash and cash equivalents at beginning of period 16us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
131us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
16us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Cash and cash equivalents at end of period 8us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
16us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
131us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 203us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
201us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
266us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Cash paid for (received from) income taxes 59us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
(84)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
24us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 100us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
88us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
139us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Asset retirement obligation additions for spent nuclear fuel disposal related to the Progress Energy merger     139duk_AssetRetirementObligationAdditionsForSpentNuclearFuelDisposal
/ dei_LegalEntityAxis
= duk_DukeEnergyFloridaMember
Duke Energy Ohio [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income (495)us-gaap_ProfitLoss
/ dei_LegalEntityAxis
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102us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
175us-gaap_ProfitLoss
/ dei_LegalEntityAxis
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Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 258us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
357us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
342us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
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Equity component of AFUDC (4)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
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(1)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
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(6)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
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(Gains) losses on sales of other assets (1)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(5)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(7)us-gaap_GainLossOnSaleOfOtherAssets
/ dei_LegalEntityAxis
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Impairment charges 941us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
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5us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
2us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
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Deferred income taxes (219)us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
98us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
61us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
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Accrued pension and other post-retirement benefit costs 8us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
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17us-gaap_PensionAndOtherPostretirementBenefitExpense
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11us-gaap_PensionAndOtherPostretirementBenefitExpense
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(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions 27us-gaap_UnrealizedGainLossOnDerivatives
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17us-gaap_UnrealizedGainLossOnDerivatives
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(5)us-gaap_UnrealizedGainLossOnDerivatives
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Receivables (56)us-gaap_IncreaseDecreaseInReceivables
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(15)us-gaap_IncreaseDecreaseInReceivables
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29us-gaap_IncreaseDecreaseInReceivables
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Receivables from affiliated companies 14us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
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(39)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
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61us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
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Inventory 8us-gaap_IncreaseDecreaseInInventories
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(3)us-gaap_IncreaseDecreaseInInventories
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15us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
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Other current assets (5)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
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(1)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
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(62)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
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Increase (decrease) in [Abstract]      
Accounts payable 27us-gaap_IncreaseDecreaseInAccountsPayable
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13us-gaap_IncreaseDecreaseInAccountsPayable
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5us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
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Accounts payable to affiliated companies (3)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
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15us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
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(22)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
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Taxes accrued (9)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
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1us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
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(24)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
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Other current liabilities 27us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
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14us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
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(21)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
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Other assets (4)us-gaap_IncreaseDecreaseInOtherOperatingAssets
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(6)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
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6us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
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Other liabilities (33)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
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(73)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(116)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Net cash provided by (used in) operating activities 481us-gaap_NetCashProvidedByUsedInOperatingActivities
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= duk_DukeEnergyOhioMember
496us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
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444us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
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Net Income (Loss) Attributable to Parent (495)us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
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102us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
175us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (322.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(434.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(514.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
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Net proceeds from the sales of equity investments and other assets, and sales of and collections on notes receivable   11us-gaap_ProceedsFromSaleOfProductiveAssets
/ dei_LegalEntityAxis
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82us-gaap_ProceedsFromSaleOfProductiveAssets
/ dei_LegalEntityAxis
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Notes receivable from affiliated companies (88)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
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(56)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
400us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
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Other (12)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
1us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
6us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Net cash (used in) provided by investing activities (422)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(478)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(26)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt   450us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
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Payments for the redemption of long-term debt (449)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(258)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(556)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Notes payable to affiliated companies 473us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
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(202)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
245us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Dividends or distributions to parent (100)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
  (175)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Other 1us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
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(3)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
 
Net cash provided by (used in) financing activities (75)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(13)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(486)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Net increase (decrease) in cash and cash equivalents (16)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
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5us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
(68)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Cash and cash equivalents at beginning of period 36us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
31us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
99us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Cash and cash equivalents at end of period 20us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
36us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
31us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 76us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
71us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
93us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Cash paid for (received from) income taxes (5)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
9us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
18us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 24us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
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27us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
31us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
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Transfer of Vermillion Generating Station     28us-gaap_TransferOfOtherRealEstate
/ dei_LegalEntityAxis
= duk_DukeEnergyOhioMember
Duke Energy Indiana [Member]      
CASH FLOWS FROM OPERATING ACTIVITIES [Abstract]      
Net income 359us-gaap_ProfitLoss
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358us-gaap_ProfitLoss
/ dei_LegalEntityAxis
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Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]      
Depreciation, amortization and accretion (including amortization of nuclear fuel) 416us-gaap_DepreciationDepletionAndAmortization
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346us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
393us-gaap_DepreciationDepletionAndAmortization
/ dei_LegalEntityAxis
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Equity component of AFUDC (14)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
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(15)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(84)us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
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Impairment charges     579us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
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Deferred income taxes 308us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
304us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
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(74)us-gaap_DeferredIncomeTaxesAndTaxCredits
/ dei_LegalEntityAxis
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Accrued pension and other post-retirement benefit costs 16us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
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25us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
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15us-gaap_PensionAndOtherPostretirementBenefitExpense
/ dei_LegalEntityAxis
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(Increase) decrease in [Abstract]      
Net realized and unrealized mark-to-market and hedging transactions   (30)us-gaap_UnrealizedGainLossOnDerivatives
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Receivables (35)us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
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3us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
6us-gaap_IncreaseDecreaseInReceivables
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Receivables from affiliated companies 36us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
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(47)us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
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52us-gaap_IncreaseDecreaseInAccountsReceivableRelatedParties
/ dei_LegalEntityAxis
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Inventory (103)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(53)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(50)us-gaap_IncreaseDecreaseInInventories
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Other current assets (8)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(40)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(25)us-gaap_IncreaseDecreaseInOtherCurrentAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Increase (decrease) in [Abstract]      
Accounts payable (41)us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
32us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
18us-gaap_IncreaseDecreaseInAccountsPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Accounts payable to affiliated companies 2us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(4)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(12)us-gaap_IncreaseDecreaseInAccountsPayableRelatedParties
/ dei_LegalEntityAxis
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Taxes accrued (32)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(30)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(27)us-gaap_IncreaseDecreaseInAccruedTaxesPayable
/ dei_LegalEntityAxis
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Other current liabilities 5us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
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(5)us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
6us-gaap_IncreaseDecreaseInOtherCurrentLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Other assets (21)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(16)us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
6us-gaap_IncreaseDecreaseInOtherOperatingAssets
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Other liabilities 17us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(84)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(37)us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Net cash provided by (used in) operating activities 905us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
744us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
716us-gaap_NetCashProvidedByUsedInOperatingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Net Income (Loss) Attributable to Parent 359us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
358us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
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(50)us-gaap_NetIncomeLoss
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
CASH FLOWS FROM INVESTING ACTIVITIES [Abstract]      
Capital expenditures (625.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(545.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(718.0)us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Purchases of available-for-sale securities (20)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
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(11)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
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(17)us-gaap_PaymentsToAcquireAvailableForSaleSecurities
/ dei_LegalEntityAxis
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Proceeds from sales and maturities of available-for-sale securities 16us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
7us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
18us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Notes receivable from affiliated companies 96us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(96)us-gaap_ProceedsFromCollectionOfAdvanceToAffiliate
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
 
Other 4us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(3)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(1)us-gaap_PaymentsForProceedsFromOtherInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Net cash (used in) provided by investing activities (529)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(648)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(718)us-gaap_NetCashProvidedByUsedInInvestingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
CASH FLOWS FROM FINANCING ACTIVITIES [Abstract]      
Proceeds from the issuance of long-term debt   498us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
250us-gaap_ProceedsFromIssuanceOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Payments for the redemption of long-term debt (5)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(405)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(7)us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Notes payable to affiliated companies 71us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(81)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(219)us-gaap_ProceedsFromRepaymentsOfRelatedPartyDebt
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Dividends or distributions to parent (450)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(125)us-gaap_PaymentsOfDistributionsToAffiliates
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
 
Other (1)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(4)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(2)us-gaap_ProceedsFromPaymentsForOtherFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Net cash provided by (used in) financing activities (385)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(117)us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
22us-gaap_NetCashProvidedByUsedInFinancingActivities
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Net increase (decrease) in cash and cash equivalents (9)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
(21)us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
20us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Cash and cash equivalents at beginning of period 15us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
36us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
16us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Cash and cash equivalents at end of period 6us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
15us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
36us-gaap_CashAndCashEquivalentsAtCarryingValue
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Supplemental Disclosures [Abstract]      
Cash paid for interest, net of amount capitalized 169us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
194us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
130us-gaap_InterestPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Cash paid for (received from) income taxes (61)us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
46us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
57us-gaap_IncomeTaxesPaidNet
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Significant Non-cash Transactions [Abstract]      
Accrued capital expenditures 87us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
73us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
67us-gaap_CapitalExpendituresIncurredButNotYetPaid
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember
Transfer of Vermillion Generating Station     $ 26us-gaap_TransferOfOtherRealEstate
/ dei_LegalEntityAxis
= duk_DukeEnergyIndianaMember