Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 13,318	$ 10,467	$ 10,175
Less: current portion	881	919
Total noncurrent asset retirement obligation	12,437	9,548
Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,633
Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,333
Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	352
Duke Energy Carolinas
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,734	3,949	3,610
Less: current portion	206	290
Total noncurrent asset retirement obligation	5,528	3,659
Duke Energy Carolinas | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,551
Duke Energy Carolinas | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	3,118
Duke Energy Carolinas | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	65
Progress Energy
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,471	5,411	5,414
Less: current portion	485	514
Total noncurrent asset retirement obligation	5,986	4,897
Progress Energy | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	4,028
Progress Energy | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,368
Progress Energy | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	75
Duke Energy Progress
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,893	4,820	4,673
Less: current portion	485	509
Total noncurrent asset retirement obligation	5,408	4,311
Duke Energy Progress | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	3,499
Duke Energy Progress | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,352
Duke Energy Progress | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	42
Duke Energy Florida
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	578	591	742
Less: current portion		5
Total noncurrent asset retirement obligation	578	586
Duke Energy Florida | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	529
Duke Energy Florida | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	16
Duke Energy Florida | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	33
Duke Energy Ohio
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	80	93	84
Less: current portion	1	6
Total noncurrent asset retirement obligation	79	87
Duke Energy Ohio | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	41
Duke Energy Ohio | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	39
Duke Energy Indiana
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	832	722	781
Less: current portion	189	109
Total noncurrent asset retirement obligation	643	613
Duke Energy Indiana | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	805
Duke Energy Indiana | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	27
Piedmont
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	17	19	$ 15
Total noncurrent asset retirement obligation	17	$ 19
Piedmont | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 17