Investments in Debt and Equity Securities (Estimated Fair Value of Investments in Debt and Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale
Estimated Fair Value	$ 2,873
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	4,086	$ 3,682
Unrealized Holding Losses	277	395
Estimated Fair Value	9,672	9,051
Duke Energy Carolinas
Debt Securities, Available-for-sale
Estimated Fair Value	1,329
Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	1,291
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,679	1,512
Unrealized Holding Losses	118	167
Estimated Fair Value	4,081	3,890
Duke Energy Progress
Debt Securities, Available-for-sale
Estimated Fair Value	977
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,592	1,432
Unrealized Holding Losses	98	142
Estimated Fair Value	3,646	3,439
Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value	314
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	87	80
Unrealized Holding Losses	20	25
Estimated Fair Value	434	450
Duke Energy Indiana
Debt Securities, Available-for-sale
Estimated Fair Value	64
NDTF
Available-for-sale Securities
Cash and cash equivalents	161	215
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	4,048	3,658
Equity Securities, FV-NI, Accumulated Unrealized Loss	60	105
Equity securities, FV-NI	6,367	5,871
Debt Securities, Available-for-sale
Estimated Fair Value	2,595	2,550
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	4,061	3,661
Unrealized Holding Losses	252	359
Estimated Fair Value	9,123	8,636
NDTF | Duke Energy Carolinas
Available-for-sale Securities
Cash and cash equivalents	69	117
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	2,375	2,147
Equity Securities, FV-NI, Accumulated Unrealized Loss	29	51
Equity securities, FV-NI	3,677	3,367
Debt Securities, Available-for-sale
Estimated Fair Value	1,329	1,298
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,382	2,149
Unrealized Holding Losses	134	192
Estimated Fair Value	5,075	4,782
NDTF | Progress Energy
Available-for-sale Securities
Cash and cash equivalents	92	98
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,673	1,511
Equity Securities, FV-NI, Accumulated Unrealized Loss	31	54
Equity securities, FV-NI	2,690	2,504
Debt Securities, Available-for-sale
Estimated Fair Value	1,266	1,252
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,679	1,512
Unrealized Holding Losses	118	167
Estimated Fair Value	4,048	3,854
NDTF | Duke Energy Progress
Available-for-sale Securities
Cash and cash equivalents	72	56
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	1,586	1,431
Equity Securities, FV-NI, Accumulated Unrealized Loss	31	54
Equity securities, FV-NI	2,590	2,411
Debt Securities, Available-for-sale
Estimated Fair Value	977	963
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	1,592	1,432
Unrealized Holding Losses	98	142
Estimated Fair Value	3,639	3,430
NDTF | Duke Energy Florida
Available-for-sale Securities
Cash and cash equivalents	20	42
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	87	80
Equity securities, FV-NI	100	93
Debt Securities, Available-for-sale
Estimated Fair Value	289	289
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	87	80
Unrealized Holding Losses	20	25
Estimated Fair Value	409	424
Other Investments
Available-for-sale Securities
Cash and cash equivalents	134	22
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	25	21
Equity Securities, FV-NI, Accumulated Unrealized Loss	11	16
Equity securities, FV-NI	137	128
Debt Securities, Available-for-sale
Estimated Fair Value	278	265
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	25	21
Unrealized Holding Losses	25	36
Estimated Fair Value	549	415
Other Investments | Progress Energy
Available-for-sale Securities
Cash and cash equivalents	8	11
Debt Securities, Available-for-sale
Estimated Fair Value	25	25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	33	36
Other Investments | Duke Energy Progress
Available-for-sale Securities
Cash and cash equivalents	7	9
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	7	9
Other Investments | Duke Energy Florida
Available-for-sale Securities
Cash and cash equivalents		1
Debt Securities, Available-for-sale
Estimated Fair Value	25	25
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Estimated Fair Value	25	26
Other Investments | Duke Energy Indiana
Available-for-sale Securities
Cash and cash equivalents	1	1
Equity Securities, FV-NI
Equity Securities, FV-NI, Accumulated Unrealized Gain	3	2
Equity Securities, FV-NI, Accumulated Unrealized Loss	11	16
Equity securities, FV-NI	85	79
Debt Securities, Available-for-sale
Estimated Fair Value	64	60
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	3	2
Unrealized Holding Losses	13	20
Estimated Fair Value	150	140
Corporate debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	3	1
Gross Unrealized Holding Losses	65	85
Estimated Fair Value	616	641
Corporate debt securities | NDTF | Duke Energy Carolinas
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	2	1
Gross Unrealized Holding Losses	47	62
Estimated Fair Value	384	401
Corporate debt securities | NDTF | Progress Energy
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	18	23
Estimated Fair Value	232	240
Corporate debt securities | NDTF | Duke Energy Progress
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	17	22
Estimated Fair Value	222	230
Corporate debt securities | NDTF | Duke Energy Florida
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	10	10
Corporate debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	10	12
Estimated Fair Value	87	84
Corporate debt securities | Other Investments | Duke Energy Indiana
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 Gains	1
Gross Unrealized Holding Losses	27	39
Estimated Fair Value	337	330
Municipal bonds | NDTF | Duke Energy Carolinas
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	5	10
Estimated Fair Value	56	64
Municipal bonds | NDTF | Progress Energy
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	22	29
Estimated Fair Value	281	266
Municipal bonds | NDTF | Duke Energy Progress
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	22	29
Estimated Fair Value	281	266
Municipal bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	2	3
Estimated Fair Value	80	78
Municipal bonds | Other Investments | Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	25	25
Municipal bonds | Other Investments | Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value	25	25
Municipal bonds | Other Investments | Duke Energy Indiana
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	2	3
Estimated Fair Value	46	45
U.S. government bonds | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	9	2
Gross Unrealized Holding Losses	85	112
Estimated Fair Value	1,495	1,423
U.S. government bonds | NDTF | Duke Energy Carolinas
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	5	1
Gross Unrealized Holding Losses	38	51
Estimated Fair Value	746	685
U.S. government bonds | NDTF | Progress Energy
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	1
Gross Unrealized Holding Losses	47	61
Estimated Fair Value	749	738
U.S. government bonds | NDTF | Duke Energy Progress
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	1
Gross Unrealized Holding Losses	28	37
Estimated Fair Value	470	460
U.S. government bonds | NDTF | Duke Energy Florida
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	19	24
Estimated Fair Value	279	278
U.S. government bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses		2
Estimated Fair Value	69	62
U.S. government bonds | Other Investments | Duke Energy Indiana
Debt Securities, Available-for-sale
Estimated Fair Value	9	7
Other debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	15	18
Estimated Fair Value	147	156
Other debt securities | NDTF | Duke Energy Carolinas
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	15	18
Estimated Fair Value	143	148
Other debt securities | NDTF | Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	4	8
Other debt securities | NDTF | Duke Energy Progress
Debt Securities, Available-for-sale
Estimated Fair Value	4	7
Other debt securities | NDTF | Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value		1
Other debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Losses	2	3
Estimated Fair Value	$ 42	$ 41