Organization and Basis of Presentation (Schedule of Inventory) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Public Utilities, Inventory [Line Items]
Inventory	$ 3,289	$ 3,232
Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	2,220	2,297
Coal
Public Utilities, Inventory [Line Items]
Inventory	776	586
Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	293	349
Duke Energy Carolinas
Public Utilities, Inventory [Line Items]
Inventory	1,080	996
Duke Energy Carolinas | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	769	768
Duke Energy Carolinas | Coal
Public Utilities, Inventory [Line Items]
Inventory	271	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	1,466	1,423
Progress Energy | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	1,014	1,038
Progress Energy | Coal
Public Utilities, Inventory [Line Items]
Inventory	257	186
Progress Energy | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	195	199
Duke Energy Progress
Public Utilities, Inventory [Line Items]
Inventory	980	934
Duke Energy Progress | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	682	686
Duke Energy Progress | Coal
Public Utilities, Inventory [Line Items]
Inventory	189	138
Duke Energy Progress | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	109	110
Duke Energy Florida
Public Utilities, Inventory [Line Items]
Inventory	486	489
Duke Energy Florida | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	333	351
Duke Energy Florida | Coal
Public Utilities, Inventory [Line Items]
Inventory	68	48
Duke Energy Florida | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	85	90
Duke Energy Ohio
Public Utilities, Inventory [Line Items]
Inventory	129	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	13	15
Duke Energy Ohio | Natural gas, oil and other fuel
Public Utilities, Inventory [Line Items]
Inventory	33	41
Duke Energy Indiana
Public Utilities, Inventory [Line Items]
Inventory	489	517
Duke Energy Indiana | Materials and supplies
Public Utilities, Inventory [Line Items]
Inventory	254	318
Duke Energy Indiana | Coal
Public Utilities, Inventory [Line Items]
Inventory	234	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	29	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	$ 24	$ 67