Derivatives and Hedging (Schedule of Offsetting Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Gross amounts recognized	$ 25	$ 57
Net amounts presented on Balance Sheets	25	57
Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	24	38
Gross amounts offset	(1)	(3)
Net amounts presented on Balance Sheets	23	35
Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	19
Gross amounts offset		(3)
Net amounts presented on Balance Sheets	1	16
Duke Energy Carolinas
Offsetting Assets [Line Items]
Gross amounts recognized		3
Net amounts presented on Balance Sheets		3
Duke Energy Carolinas | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Carolinas | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		1
Gross amounts offset		(1)
Progress Energy
Offsetting Assets [Line Items]
Gross amounts recognized	7	4
Net amounts presented on Balance Sheets	7	4
Progress Energy | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	7	2
Gross amounts offset	(1)	(2)
Net amounts presented on Balance Sheets	6
Progress Energy | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress
Offsetting Assets [Line Items]
Gross amounts recognized		4
Net amounts presented on Balance Sheets		4
Duke Energy Progress | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(2)
Duke Energy Progress | Noncurrent assets
Offsetting Assets [Line Items]
Gross amounts recognized		2
Gross amounts offset		(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	4	6
Duke Energy Ohio | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	3	6
Net amounts presented on Balance Sheets	3	6
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	13	23
Net amounts presented on Balance Sheets	13	23
Duke Energy Indiana | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	13	23
Net amounts presented on Balance Sheets	13	23
Piedmont
Offsetting Assets [Line Items]
Gross amounts recognized	1	3
Net amounts presented on Balance Sheets	1	3
Piedmont | Current Assets
Offsetting Assets [Line Items]
Gross amounts recognized	1	3
Net amounts presented on Balance Sheets	$ 1	$ 3