Goodwill and Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	$ 355	$ 305
Accumulated amortization	(60)	(56)
Total intangible assets, net	295	249
Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	8	18
Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	196	172
Natural gas, coal and power contracts
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	(23)	(21)
Renewable operating and development projects
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	107	89
Accumulated amortization	(34)	(34)
Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	20	2
Accumulated amortization	(3)	(1)
Duke Energy Carolinas
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	65	53
Total intangible assets, net	65	53
Duke Energy Carolinas | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	65	53
Progress Energy
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	135	123
Total intangible assets, net	135	123
Progress Energy | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	5	5
Progress Energy | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	130	118
Duke Energy Progress
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	132	120
Total intangible assets, net	132	120
Duke Energy Progress | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	2
Duke Energy Progress | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	130	118
Duke Energy Florida
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Total intangible assets, net	3	3
Duke Energy Florida | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Duke Energy Ohio
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	1	1
Total intangible assets, net	1	1
Duke Energy Ohio | Renewable energy certificates
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	1	1
Duke Energy Indiana
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	26	36
Accumulated amortization	(23)	(21)
Total intangible assets, net	3	15
Duke Energy Indiana | Emission allowances
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	12
Duke Energy Indiana | Natural gas, coal and power contracts
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	$ (23)	$ (21)