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Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) GWh Mcf | Dec. 31, 2019 USD ($) GWh Mcf
Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 1,809 | $ 2,270
Interest Rate Contracts | Designated contracts | Cash flow hedges |  |
Derivative [Line Items] |  |
Notional Amount | 632 | 993
Interest Rate Contracts | Undesignated contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 1,177 | $ 1,277
Commodity contracts | Electricity (GWh)(a) |  |
Derivative [Line Items] |  |
Notional amount, energy measure, in gigawatt-hours | GWh | 35,409 | 15,858
Commodity contracts | Electricity (GWh)(a) | Cash flow hedges |  |
Derivative [Line Items] |  |
Notional amount, energy measure, in gigawatt-hours | GWh | 22,048 |
Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 678 | 704
Consolidated VIEs | Interest Rate Contracts | Designated contracts | Cash flow hedges |  |
Derivative [Line Items] |  |
Notional Amount | $ 632 | $ 693
Duke Energy Carolinas | Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount | 400 | 450
Duke Energy Carolinas | Interest Rate Contracts | Undesignated contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 400 | $ 450
Duke Energy Carolinas | Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 145 | 130
Progress Energy | Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 750 | $ 800
Progress Energy | Interest Rate Contracts | Undesignated contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 750 | $ 800
Progress Energy | Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 158 | 160
Duke Energy Progress | Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 750 | $ 250
Duke Energy Progress | Interest Rate Contracts | Undesignated contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 750 | $ 250
Duke Energy Progress | Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 158 | 160
Duke Energy Florida | Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount |  | $ 550
Duke Energy Florida | Interest Rate Contracts | Undesignated contracts |  |
Derivative [Line Items] |  |
Notional Amount |  | 550
Duke Energy Ohio | Interest Rate Contracts |  |
Derivative [Line Items] |  |
Notional Amount | $ 27 | 27
Duke Energy Ohio | Interest Rate Contracts | Undesignated 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 | 2,559 | 1,887
Duke Energy Indiana | Commodity contracts | Electricity (GWh)(a) |  |
Derivative [Line Items] |  |
Notional amount, energy measure, in gigawatt-hours | GWh | 10,802 | 13,971
Duke Energy Indiana | Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 2 | 3
Piedmont | Commodity contracts | Natural gas (millions of Dth) |  |
Derivative [Line Items] |  |
Notional amount, volume in millions of decatherms | Mcf | 373 | 411

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