Derivatives and Hedging (Schedule of Offsetting Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	$ 361	$ 300
Net amounts recognized on the Condensed Consolidated Balance Sheet	361	277
Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	137	118
Gross amounts offset	(3)	(24)
Net amounts recognized on the Condensed Consolidated Balance Sheet	134	94
Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	224	182
Gross amounts offset	(4)
Net amounts recognized on the Condensed Consolidated Balance Sheet	220	182
Duke Energy Carolinas
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	57	49
Net amounts recognized on the Condensed Consolidated Balance Sheet	57	49
Duke Energy Carolinas | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	49	39
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	47	39
Duke Energy Carolinas | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	8	10
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	6	10
Progress Energy
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	121	88
Net amounts recognized on the Condensed Consolidated Balance Sheet	121	65
Progress Energy | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	65	51
Gross amounts offset	(1)	(24)
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	27
Progress Energy | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	56	37
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	54	37
Duke Energy Progress
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	105	49
Net amounts recognized on the Condensed Consolidated Balance Sheet	105	49
Duke Energy Progress | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	65	27
Gross amounts offset	(1)
Net amounts recognized on the Condensed Consolidated Balance Sheet	64	27
Duke Energy Progress | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	40	22
Gross amounts offset	(2)
Net amounts recognized on the Condensed Consolidated Balance Sheet	38	22
Duke Energy Florida
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		24
Net amounts recognized on the Condensed Consolidated Balance Sheet		1
Duke Energy Florida | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized		24
Gross amounts offset		(24)
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	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Duke Energy Indiana | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	1	1
Net amounts recognized on the Condensed Consolidated Balance Sheet	1	1
Piedmont Natural Gas
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	105	117
Net amounts recognized on the Condensed Consolidated Balance Sheet	105	117
Piedmont Natural Gas | Current liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	7	7
Net amounts recognized on the Condensed Consolidated Balance Sheet	7	7
Piedmont Natural Gas | Noncurrent liabilities
Offsetting Derivative Liabilities [Abstract]
Gross amounts recognized	98	110
Net amounts recognized on the Condensed Consolidated Balance Sheet	$ 98	$ 110