Asset Retirement Obligations (Recorded on the Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 13,004	$ 13,318	$ 10,467
Less: Current portion	718	881
Total noncurrent asset retirement obligation	12,286	12,437
Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,845
Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,778
Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	381
Duke Energy Carolinas
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	5,350	5,734	3,949
Less: Current portion	264	206
Total noncurrent asset retirement obligation	5,086	5,528
Duke Energy Carolinas | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,695
Duke Energy Carolinas | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	2,597
Duke Energy Carolinas | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	58
Progress Energy
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	6,149	6,471	5,411
Less: Current portion	283	485
Total noncurrent asset retirement obligation	5,866	5,986
Progress Energy | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	4,101
Progress Energy | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	1,973
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	5,635	5,893	4,820
Less: Current portion	283	485
Total noncurrent asset retirement obligation	5,352	5,408
Duke Energy Progress | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	3,642
Duke Energy Progress | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	1,950
Duke Energy Progress | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	43
Duke Energy Florida
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	514	578	591
Total noncurrent asset retirement obligation	514	578
Duke Energy Florida | Decommissioning of nuclear power facilities
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	459
Duke Energy Florida | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	23
Duke Energy Florida | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	32
Duke Energy Ohio
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	111	80	93
Less: Current portion	3	1
Total noncurrent asset retirement obligation	108	79
Duke Energy Ohio | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	67
Duke Energy Ohio | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	44
Duke Energy Indiana
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	1,176	832	722
Less: Current portion	168	189
Total noncurrent asset retirement obligation	1,008	643
Duke Energy Indiana | Closure of ash impoundments
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	1,140
Duke Energy Indiana | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	36
Piedmont
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	20	17	$ 19
Total noncurrent asset retirement obligation	20	$ 17
Piedmont | Other
Asset Retirement Obligation [Line Items]
Total asset retirement obligation	$ 20