Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Public Utilities, Inventory [Line Items]
Inventory	$ 3,015	$ 3,167
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	2,368	2,312
Coal
Public Utilities, Inventory [Line Items]
Inventory	397	561
Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	250	294
Duke Energy Carolinas
Public Utilities, Inventory [Line Items]
Inventory	1,013	1,010
Duke Energy Carolinas | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	820	785
Duke Energy Carolinas | Coal
Public Utilities, Inventory [Line Items]
Inventory	158	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	1,299	1,375
Progress Energy | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	1,014	999
Progress Energy | Coal
Public Utilities, Inventory [Line Items]
Inventory	123	193
Progress Energy | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	162	183
Duke Energy Progress
Public Utilities, Inventory [Line Items]
Inventory	858	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	78	131
Duke Energy Progress | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	100	107
Duke Energy Florida
Public Utilities, Inventory [Line Items]
Inventory	440	464
Duke Energy Florida | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	334	325
Duke Energy Florida | Coal
Public Utilities, Inventory [Line Items]
Inventory	44	63
Duke Energy Florida | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	62	76
Duke Energy Ohio
Public Utilities, Inventory [Line Items]
Inventory	111	110
Duke Energy Ohio | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	82	78
Duke Energy Ohio | Coal
Public Utilities, Inventory [Line Items]
Inventory	10	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	412	473
Duke Energy Indiana | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	305	307
Duke Energy Indiana | Coal
Public Utilities, Inventory [Line Items]
Inventory	106	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	43	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	$ 32	$ 56