Other Income and Expenses, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	$ 32	$ 31	$ 20
AFUDC equity	154	139	221
Post in-service equity returns	27	29	15
Nonoperating income, other	240	231	143
Other income and expense, net	453	430	399
Duke Energy Carolinas
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	4	1	1
AFUDC equity	62	42	73
Post in-service equity returns	17	20	9
Nonoperating income, other	94	88	70
Other income and expense, net	177	151	153
Progress Energy
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	8	11	18
AFUDC equity	42	66	104
Post in-service equity returns	8	7	5
Nonoperating income, other	71	57	38
Other income and expense, net	129	141	165
Duke Energy Progress
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	2	0	1
AFUDC equity	29	60	57
Post in-service equity returns	8	7	5
Nonoperating income, other	36	33	24
Other income and expense, net	75	100	87
Duke Energy Florida
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	6	11	18
AFUDC equity	12	6	47
Nonoperating income, other	35	31	21
Other income and expense, net	53	48	86
Duke Energy Ohio
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	4	10	7
AFUDC equity	7	13	11
Post in-service equity returns	1	1	1
Nonoperating income, other	4	0	4
Other income and expense, net	16	24	23
Duke Energy Indiana
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	6	10	9
AFUDC equity	23	18	32
Post in-service equity returns	1
Nonoperating income, other	7	13	4
Other income and expense, net	37	41	45
Piedmont
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	17	1	1
AFUDC equity	19
Nonoperating income, other	15	19	13
Other income and expense, net	$ 51	$ 20	$ 14