Other Income and Expenses, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	$ 31	$ 20	$ 13
AFUDC equity	139	221	237
Post in-service equity returns	29	15	40
Nonoperating income, other	231	143	218
Other income and expense, net	430	399	508
Duke Energy Carolinas
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	1	1	2
AFUDC equity	42	73	106
Post in-service equity returns	20	9	28
Nonoperating income, other	88	70	63
Other income and expense, net	151	153	199
Progress Energy
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	11	18	6
AFUDC equity	66	104	92
Post in-service equity returns	7	5	12
Nonoperating income, other	57	38	99
Other income and expense, net	141	165	209
Duke Energy Progress
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		1	2
AFUDC equity	60	57	47
Post in-service equity returns	7	5	12
Nonoperating income, other	33	24	54
Other income and expense, net	100	87	115
Duke Energy Florida
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	11	18	5
AFUDC equity	6	47	45
Nonoperating income, other	31	21	46
Other income and expense, net	48	86	96
Duke Energy Ohio
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	10	7	6
AFUDC equity	13	11	11
Post in-service equity returns	1	1
Nonoperating income, other		4	6
Other income and expense, net	24	23	23
Duke Energy Indiana
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	10	9	8
AFUDC equity	18	32	28
Post in-service equity returns	0
Nonoperating income, other	13	4	11
Other income and expense, net	41	45	47
Piedmont
Component Of Other Income Expense Nonoperating [Line Items]
Interest income	1	1
Nonoperating income, other	19	13	(11)
Other income and expense, net	$ 20	$ 14	$ (11)