Other Income and Expenses, Net (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2016
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		$ 20	$ 13	$ 21
AFUDC equity		221	237	200
Post in-service equity returns		15	40	67
Nonoperating income (expense), other		143	218	175
Other income and expenses, net		399	508	463
Duke Energy Carolinas [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		1	2	4
AFUDC equity		73	106	102
Post in-service equity returns		9	28	55
Nonoperating income (expense), other		70	63	53
Other income and expenses, net		153	199	214
Progress Energy [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		18	6	4
AFUDC equity		104	92	76
Post in-service equity returns		5	12	12
Nonoperating income (expense), other		38	99	94
Other income and expenses, net		165	209	186
Duke Energy Progress [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		1	2	3
AFUDC equity		57	47	50
Post in-service equity returns		5	12	12
Nonoperating income (expense), other		24	54	67
Other income and expenses, net		87	115	132
Duke Energy Florida [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		18	5	2
AFUDC equity		47	45	26
Nonoperating income (expense), other		21	46	35
Other income and expenses, net		86	96	63
Duke Energy Ohio [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		7	6	5
AFUDC equity		11	11	6
Post in-service equity returns		1
Nonoperating income (expense), other		4	6
Other income and expenses, net		23	23	11
Duke Energy Indiana [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		9	8	6
AFUDC equity		32	28	16
Nonoperating income (expense), other		4	11	4
Other income and expenses, net		45	47	$ 26
Piedmont Natural Gas [Member]
Component Of Other Income Expense Nonoperating [Line Items]
Interest income		1
Nonoperating income (expense), other		13	(11)
Other income and expenses, net	$ (2)	$ 14	$ (11)		$ (1)