Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Public Utilities, Inventory [Line Items]
Inventory	$ 3,324	$ 3,232
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	2,280	2,297
Coal
Public Utilities, Inventory [Line Items]
Inventory	742	586
Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	302	349
Duke Energy Carolinas
Public Utilities, Inventory [Line Items]
Inventory	1,067	996
Duke Energy Carolinas | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	759	768
Duke Energy Carolinas | Coal
Public Utilities, Inventory [Line Items]
Inventory	268	187
Duke Energy Carolinas | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	40	41
Progress Energy
Public Utilities, Inventory [Line Items]
Inventory	1,463	1,423
Progress Energy | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	1,018	1,038
Progress Energy | Coal
Public Utilities, Inventory [Line Items]
Inventory	246	186
Progress Energy | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	199	199
Duke Energy Progress
Public Utilities, Inventory [Line Items]
Inventory	956	934
Duke Energy Progress | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	678	686
Duke Energy Progress | Coal
Public Utilities, Inventory [Line Items]
Inventory	167	138
Duke Energy Progress | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	111	110
Duke Energy Florida
Public Utilities, Inventory [Line Items]
Inventory	508	489
Duke Energy Florida | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	340	351
Duke Energy Florida | Coal
Public Utilities, Inventory [Line Items]
Inventory	79	48
Duke Energy Florida | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	89	90
Duke Energy Ohio
Public Utilities, Inventory [Line Items]
Inventory	121	135
Duke Energy Ohio | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	83	79
Duke Energy Ohio | Coal
Public Utilities, Inventory [Line Items]
Inventory	10	15
Duke Energy Ohio | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	28	41
Duke Energy Indiana
Public Utilities, Inventory [Line Items]
Inventory	538	517
Duke Energy Indiana | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	319	318
Duke Energy Indiana | Coal
Public Utilities, Inventory [Line Items]
Inventory	218	198
Duke Energy Indiana | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	1	1
Piedmont Natural Gas
Public Utilities, Inventory [Line Items]
Inventory	39	72
Piedmont Natural Gas | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	5	5
Piedmont Natural Gas | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	$ 34	$ 67