Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 390	$ 300
Net amounts recognized on the Condensed Consolidated Balance Sheet	390	277
Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	178	118
Gross amounts offset		(24)
Net amounts recognized on the Condensed Consolidated Balance Sheet	178	94
Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	212	182
Gross amounts offset	(3)
Net amounts recognized on the Condensed Consolidated Balance Sheet	209	182
Duke Energy Carolinas
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	74	49
Net amounts recognized on the Condensed Consolidated Balance Sheet	74	49
Duke Energy Carolinas | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	40	39
Net amounts recognized on the Condensed Consolidated Balance Sheet	40	39
Duke Energy Carolinas | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	34	10
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	32	10
Progress Energy
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	95	88
Net amounts recognized on the Condensed Consolidated Balance Sheet	95	65
Progress Energy | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	60	51
Gross amounts offset		(24)
Net amounts recognized on the Condensed Consolidated Balance Sheet	60	27
Progress Energy | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	35	37
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	34	37
Duke Energy Progress
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	51	49
Net amounts recognized on the Condensed Consolidated Balance Sheet	51	49
Duke Energy Progress | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	31	27
Net amounts recognized on the Condensed Consolidated Balance Sheet	31	27
Duke Energy Progress | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	20	22
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	19	22
Duke Energy Florida
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	29	24
Net amounts recognized on the Condensed Consolidated Balance Sheet	29	1
Duke Energy Florida | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	29	24
Gross amounts offset		(24)
Net amounts recognized on the Condensed Consolidated Balance Sheet	29
Duke Energy Ohio
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	6
Duke Energy Ohio | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Ohio | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	6	5
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	5
Duke Energy Indiana
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		1
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Duke Energy Indiana | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		1
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Piedmont Natural Gas
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	91	117
Net amounts recognized on the Condensed Consolidated Balance Sheet	91	117
Piedmont Natural Gas | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	8	7
Piedmont Natural Gas | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	83	110
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 83	$ 110