Organization and Basis of Presentation (Confirmed Obligations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Duke Energy (Parent)
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	$ 40	$ 46	$ 87	$ 19
Invoices confirmed during the period	47	86	161	181
Confirmed invoices paid during the period	(18)	(58)	(179)	(126)
Confirmed obligations at end of period	69	74	69	74
Duke Energy Carolinas
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	5	9	6
Invoices confirmed during the period	2	6	22	20
Confirmed invoices paid during the period	(4)	(12)	(25)	(17)
Confirmed obligations at end of period	3	3	3	3
Progress Energy
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	14	11	19	9
Invoices confirmed during the period	11	21	53	52
Confirmed invoices paid during the period	(8)	(15)	(55)	(44)
Confirmed obligations at end of period	17	17	17	17
Duke Energy Progress
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	12	3	8
Invoices confirmed during the period	2	7	25	17
Confirmed invoices paid during the period	(3)	(5)	(22)	(12)
Confirmed obligations at end of period	11	5	11	5
Duke Energy Florida
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	2	8	11	9
Invoices confirmed during the period	9	14	28	35
Confirmed invoices paid during the period	(5)	(10)	(33)	(32)
Confirmed obligations at end of period	6	12	6	12
Duke Energy Ohio
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	2	9	5	6
Invoices confirmed during the period	4	12	7	27
Confirmed invoices paid during the period		(9)	(6)	(21)
Confirmed obligations at end of period	6	12	6	12
Duke Energy Indiana
Contractual Obligations [Roll Forward]
Invoices confirmed during the period				1
Confirmed invoices paid during the period				(1)
Piedmont
Contractual Obligations [Roll Forward]
Confirmed obligations at beginning of period	19	17	57	4
Invoices confirmed during the period	30	47	79	81
Confirmed invoices paid during the period	(6)	(22)	(93)	(43)
Confirmed obligations at end of period	$ 43	$ 42	$ 43	$ 42