Investments in Debt and Equity Securities (Estimated Fair Value of Investments in Debt and Equity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale
Estimated Fair Value	$ 2,824
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	4,244	$ 3,682
Unrealized Holding Losses	351	395
Estimated Fair Value	9,691	9,051
NDTF
Cash and Cash Equivalents
Estimated Fair Value	160	215
Equity Securities, FV-NI
Gross Unrealized Holding Gains	4,218	3,658
Gross Unrealized Holding Losses	44	105
Estimated Fair Value	6,530	5,871
Debt Securities, Available-for-sale
Estimated Fair Value	2,569	2,550
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	4,218	3,661
Unrealized Holding Losses	319	359
Estimated Fair Value	9,259	8,636
Other Investments
Cash and Cash Equivalents
Estimated Fair Value	36	22
Equity Securities, FV-NI
Gross Unrealized Holding Gains	26	21
Gross Unrealized Holding Losses	9	16
Estimated Fair Value	141	128
Debt Securities, Available-for-sale
Estimated Fair Value	255	265
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	26	21
Unrealized Holding Losses	32	36
Estimated Fair Value	432	415
Duke Energy Carolinas
Debt Securities, Available-for-sale
Estimated Fair Value	1,329
Duke Energy Carolinas | NDTF
Cash and Cash Equivalents
Estimated Fair Value	59	117
Equity Securities, FV-NI
Gross Unrealized Holding Gains	2,468	2,147
Gross Unrealized Holding Losses	25	51
Estimated Fair Value	3,767	3,367
Debt Securities, Available-for-sale
Estimated Fair Value	1,329	1,298
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,468	2,149
Unrealized Holding Losses	185	192
Estimated Fair Value	5,155	4,782
Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	1,263
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,750	1,512
Unrealized Holding Losses	134	167
Estimated Fair Value	4,135	3,890
Progress Energy | NDTF
Cash and Cash Equivalents
Estimated Fair Value	101	98
Equity Securities, FV-NI
Gross Unrealized Holding Gains	1,750	1,511
Gross Unrealized Holding Losses	19	54
Estimated Fair Value	2,763	2,504
Debt Securities, Available-for-sale
Estimated Fair Value	1,240	1,252
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,750	1,512
Unrealized Holding Losses	134	167
Estimated Fair Value	4,104	3,854
Progress Energy | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	8	11
Debt Securities, Available-for-sale
Estimated Fair Value	23	25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	31	36
Duke Energy Progress
Debt Securities, Available-for-sale
Estimated Fair Value	971
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,661	1,432
Unrealized Holding Losses	113	142
Estimated Fair Value	3,700	3,439
Duke Energy Progress | NDTF
Cash and Cash Equivalents
Estimated Fair Value	62	56
Equity Securities, FV-NI
Gross Unrealized Holding Gains	1,661	1,431
Gross Unrealized Holding Losses	19	54
Estimated Fair Value	2,663	2,411
Debt Securities, Available-for-sale
Estimated Fair Value	971	963
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,661	1,432
Unrealized Holding Losses	113	142
Estimated Fair Value	3,696	3,430
Duke Energy Progress | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	4	9
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	4	9
Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value	292
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	89	80
Unrealized Holding Losses	21	25
Estimated Fair Value	432	450
Duke Energy Florida | NDTF
Cash and Cash Equivalents
Estimated Fair Value	39	42
Equity Securities, FV-NI
Gross Unrealized Holding Gains	89	80
Estimated Fair Value	100	93
Debt Securities, Available-for-sale
Estimated Fair Value	269	289
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	89	80
Unrealized Holding Losses	21	25
Estimated Fair Value	408	424
Duke Energy Florida | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	1	1
Debt Securities, Available-for-sale
Estimated Fair Value	23	25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	24	26
Duke Energy Indiana
Debt Securities, Available-for-sale
Estimated Fair Value	59
Duke Energy Indiana | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	3	1
Equity Securities, FV-NI
Gross Unrealized Holding Gains	3	2
Gross Unrealized Holding Losses	9	16
Estimated Fair Value	88	79
Debt Securities, Available-for-sale
Estimated Fair Value	59	60
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	3	2
Unrealized Holding Losses	12	20
Estimated Fair Value	150	140
Corporate debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	80	85
Estimated Fair Value	612	641
Corporate debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	10	12
Estimated Fair Value	83	84
Corporate debt securities | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	60	62
Estimated Fair Value	376	401
Corporate debt securities | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	20	23
Estimated Fair Value	236	240
Corporate debt securities | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	19	22
Estimated Fair Value	224	230
Corporate debt securities | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	12	10
Corporate debt securities | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses		1
Estimated Fair Value	9	8
Municipal bonds | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	41	39
Estimated Fair Value	318	330
Municipal bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	3	3
Estimated Fair Value	74	78
Municipal bonds | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	9	10
Estimated Fair Value	45	64
Municipal bonds | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	32	29
Estimated Fair Value	273	266
Municipal bonds | Progress Energy | Other Investments
Debt Securities, Available-for-sale
Estimated Fair Value	23	25
Municipal bonds | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	32	29
Estimated Fair Value	273	266
Municipal bonds | Duke Energy Florida | Other Investments
Debt Securities, Available-for-sale
Estimated Fair Value	23	25
Municipal bonds | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	3	3
Estimated Fair Value	44	45
U.S. government bonds | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		2
Gross Unrealized Holding Losses	136	112
Estimated Fair Value	1,470	1,423
U.S. government bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	5	2
Estimated Fair Value	46	62
U.S. government bonds | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	73	51
Estimated Fair Value	745	685
U.S. government bonds | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	63	61
Estimated Fair Value	725	738
U.S. government bonds | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains		1
Gross Unrealized Holding Losses	43	37
Estimated Fair Value	469	460
U.S. government bonds | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	20	24
Estimated Fair Value	256	278
U.S. government bonds | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Estimated Fair Value	6	7
Other debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	18	18
Estimated Fair Value	169	156
Other debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	5	3
Estimated Fair Value	52	41
Other debt securities | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	18	18
Estimated Fair Value	163	148
Other debt securities | Progress Energy | NDTF
Debt Securities, Available-for-sale
Estimated Fair Value	6	8
Other debt securities | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Estimated Fair Value	5	7
Other debt securities | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Estimated Fair Value	$ 1	$ 1