Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Public Utilities, Inventory [Line Items]
Inventory	$ 3,076	$ 3,167
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	2,365	2,312
Coal
Public Utilities, Inventory [Line Items]
Inventory	464	561
Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	247	294
Duke Energy Carolinas
Public Utilities, Inventory [Line Items]
Inventory	1,021	1,010
Duke Energy Carolinas | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	816	785
Duke Energy Carolinas | Coal
Public Utilities, Inventory [Line Items]
Inventory	170	186
Duke Energy Carolinas | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	35	39
Progress Energy
Public Utilities, Inventory [Line Items]
Inventory	1,336	1,375
Progress Energy | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	1,011	999
Progress Energy | Coal
Public Utilities, Inventory [Line Items]
Inventory	160	193
Progress Energy | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	165	183
Duke Energy Progress
Public Utilities, Inventory [Line Items]
Inventory	882	911
Duke Energy Progress | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	680	673
Duke Energy Progress | Coal
Public Utilities, Inventory [Line Items]
Inventory	101	131
Duke Energy Progress | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	101	107
Duke Energy Florida
Public Utilities, Inventory [Line Items]
Inventory	455	464
Duke Energy Florida | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	332	325
Duke Energy Florida | Coal
Public Utilities, Inventory [Line Items]
Inventory	59	63
Duke Energy Florida | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	64	76
Duke Energy Ohio
Public Utilities, Inventory [Line Items]
Inventory	108	110
Duke Energy Ohio | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	77	78
Duke Energy Ohio | Coal
Public Utilities, Inventory [Line Items]
Inventory	12	16
Duke Energy Ohio | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	19	16
Duke Energy Indiana
Public Utilities, Inventory [Line Items]
Inventory	436	473
Duke Energy Indiana | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	313	307
Duke Energy Indiana | Coal
Public Utilities, Inventory [Line Items]
Inventory	122	165
Duke Energy Indiana | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	1	1
Piedmont
Public Utilities, Inventory [Line Items]
Inventory	37	68
Piedmont | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	11	12
Piedmont | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	$ 26	$ 56