Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	$ 34	$ 25
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	25
Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	9	24
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	9	23
Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	25	1
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	1
Net amounts presented in NDTF
Offsetting Derivative Assets [Abstract]
Net amounts recognized on the Condensed Consolidated Balance Sheet	20
Duke Energy Carolinas
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Net amounts recognized on the Condensed Consolidated Balance Sheet	2
Duke Energy Carolinas | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Gross amounts offset	(2)
Progress Energy
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	25	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	25	7
Progress Energy | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	7
Gross amounts offset		(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	6
Progress Energy | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	22
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Progress Energy | Net amounts presented in NDTF
Offsetting Derivative Assets [Abstract]
Net amounts recognized on the Condensed Consolidated Balance Sheet	20
Duke Energy Progress
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	5
Duke Energy Progress | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3
Net amounts recognized on the Condensed Consolidated Balance Sheet	3
Duke Energy Progress | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	1
Duke Energy Florida
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20	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 Florida | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	20
Duke Energy Florida | Net amounts presented in NDTF
Offsetting Derivative Assets [Abstract]
Net amounts recognized on the Condensed Consolidated Balance Sheet	20
Duke Energy Ohio
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	4
Duke Energy Ohio | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized		3
Net amounts recognized on the Condensed Consolidated Balance Sheet		3
Duke Energy Ohio | Noncurrent assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Indiana
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	13
Duke Energy Indiana | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	2	13
Net amounts recognized on the Condensed Consolidated Balance Sheet	2	13
Piedmont Natural Gas
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	3	1
Piedmont Natural Gas | Current assets
Offsetting Derivative Assets [Abstract]
Gross amounts recognized	3	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 3	$ 1