Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Gross amounts recognized	$ 61	$ 25
Net amounts presented on Balance Sheets	61	25
Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	48	24
Gross amounts offset	(3)	(1)
Net amounts presented on Balance Sheets	45	23
Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	13	1
Gross amounts offset	(5)
Net amounts presented on Balance Sheets	8	1
Duke Energy Carolinas
Offsetting Assets [Line Items]
Gross amounts recognized	20
Duke Energy Carolinas | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	14
Gross amounts offset	(2)
Net amounts presented on Balance Sheets	12
Duke Energy Carolinas | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	6
Gross amounts offset	(1)
Net amounts presented on Balance Sheets	5
Progress Energy
Offsetting Assets [Line Items]
Gross amounts recognized	33	7
Net amounts presented on Balance Sheets	33	7
Progress Energy | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	27	7
Gross amounts offset	(2)	(1)
Net amounts presented on Balance Sheets	25	6
Progress Energy | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	6
Gross amounts offset	(4)
Net amounts presented on Balance Sheets	2
Duke Energy Progress
Offsetting Assets [Line Items]
Gross amounts recognized	33
Net amounts presented on Balance Sheets	33
Duke Energy Progress | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	27
Gross amounts offset	(2)
Net amounts presented on Balance Sheets	25
Duke Energy Progress | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	6
Gross amounts offset	(4)
Net amounts presented on Balance Sheets	2
Duke Energy Florida
Offsetting Assets [Line Items]
Gross amounts recognized		7
Net amounts presented on Balance Sheets		7
Duke Energy Florida | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized		7
Gross amounts offset		(1)
Net amounts presented on Balance Sheets		6
Duke Energy Ohio
Offsetting Assets [Line Items]
Gross amounts recognized	1	4
Duke Energy Ohio | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	3
Net amounts presented on Balance Sheets	1	3
Duke Energy Ohio | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		1
Net amounts presented on Balance Sheets		1
Duke Energy Indiana
Offsetting Assets [Line Items]
Gross amounts recognized	6	13
Net amounts presented on Balance Sheets	6	13
Duke Energy Indiana | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	6	13
Net amounts presented on Balance Sheets	6	13
Piedmont
Offsetting Assets [Line Items]
Gross amounts recognized	1	1
Net amounts presented on Balance Sheets	1	1
Piedmont | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	1
Net amounts presented on Balance Sheets	$ 1	$ 1