Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 206	$ 61
Net amounts recognized on the Condensed Consolidated Balance Sheet	206	61
Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	192	48
Gross amounts offset		(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	192	45
Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	14	13
Gross amounts offset	(4)	(5)
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	8
Duke Energy Carolinas
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	62	20
Net amounts recognized on the Condensed Consolidated Balance Sheet	62	20
Duke Energy Carolinas | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	55	14
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	55	12
Duke Energy Carolinas | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	6
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	5
Progress Energy
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	103	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	103	33
Progress Energy | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	96	27
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	96	25
Progress Energy | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	6
Gross amounts offset	(4)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	2
Duke Energy Progress
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	100	33
Net amounts recognized on the Condensed Consolidated Balance Sheet	100	33
Duke Energy Progress | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	93	27
Gross amounts offset		(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	93	25
Duke Energy Progress | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7	6
Gross amounts offset	(4)	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	2
Duke Energy Florida
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Florida | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Ohio
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		1
Duke Energy Ohio | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		1
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Duke Energy Indiana
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	6
Duke Energy Indiana | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	6
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	6
Piedmont
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Piedmont | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 1	$ 1