Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) GWh Mcf	Jun. 30, 2020 GWh Mcf	Dec. 31, 2020 USD ($) GWh
Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 3,361		$ 1,809
Commodity contracts | Cash flow hedges
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	10,720		22,048
Commodity contracts | Electricity (GWh)(a)
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	16,259	35,409
Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	675	678
Designated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 1,630		$ 632
Designated contracts | Interest Rate Contracts | VIE primary beneficiary
Derivative [Line Items]
Notional amount	631		632
Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	1,731		1,177
Undesignated contracts | Interest Rate Contracts | VIE primary beneficiary
Derivative [Line Items]
Notional amount	54
Duke Energy Carolinas | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 400		400
Duke Energy Carolinas | Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	151	145
Duke Energy Carolinas | Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 400		400
Progress Energy | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 1,250		750
Progress Energy | Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	158	158
Progress Energy | Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 1,250		750
Duke Energy Progress | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 750		750
Duke Energy Progress | Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	158	158
Duke Energy Progress | Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 750		750
Duke Energy Florida | Interest Rate Contracts
Derivative [Line Items]
Notional amount	500
Duke Energy Florida | Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	500
Duke Energy Ohio | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 27		27
Duke Energy Ohio | Commodity contracts | Electricity (GWh)(a)
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	1,325	2,559
Duke Energy Ohio | Undesignated contracts | Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 27		$ 27
Duke Energy Indiana | Commodity contracts | Electricity (GWh)(a)
Derivative [Line Items]
Notional amount, energy measure (in gigawatt-hours) | GWh	4,214	10,802
Duke Energy Indiana | Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	2	2
Piedmont | Commodity contracts | Natural gas (millions of dekatherms)
Derivative [Line Items]
Notional amount, volume (in millions of dekatherms) | Mcf	364	373