Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 32	$ 25
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	25
Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	23	24
Gross amounts offset	(3)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	20	23
Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	1
Gross amounts offset	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	5	1
Duke Energy Carolinas
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	7
Duke Energy Carolinas | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Gross amounts offset	(2)
Duke Energy Carolinas | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Progress Energy
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	7
Progress Energy | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	7
Gross amounts offset	(1)	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	6
Progress Energy | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Progress
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	8
Net amounts recognized on the Condensed Consolidated Balance Sheet	8
Duke Energy Progress | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Progress | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Florida
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		7
Net amounts recognized on the Condensed Consolidated Balance Sheet		7
Duke Energy Florida | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		7
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet		6
Duke Energy Ohio
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	4
Duke Energy Ohio | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	3
Duke Energy Ohio | Noncurrent 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	10	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	13
Duke Energy Indiana | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	10	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	10	13
Piedmont Natural Gas
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	4	1
Piedmont Natural Gas | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	4	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 4	$ 1