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Investments in Debt and Equity Securities (Estimated Fair Value of Investments in Debt and Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale
Estimated Fair Value	$ 3,081
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	5,621	$ 5,019
Unrealized Holding Losses	191	171
Estimated Fair Value	11,252	10,603
NDTF
Cash and Cash Equivalents
Estimated Fair Value	140	133
Equity Securities, FV-NI
Gross Unrealized Holding Gains	5,553	4,942
Gross Unrealized Holding Losses	27	22
Estimated Fair Value	7,837	7,278
Debt Securities, Available-for-sale
Estimated Fair Value	2,810	2,732
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	5,574	4,985
Unrealized Holding Losses	178	159
Estimated Fair Value	10,787	10,143
Other Investments
Cash and Cash Equivalents
Estimated Fair Value	21	31
Equity Securities, FV-NI
Gross Unrealized Holding Gains	47	33
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	173	158
Debt Securities, Available-for-sale
Estimated Fair Value	271	271
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	47	34
Unrealized Holding Losses	13	12
Estimated Fair Value	465	460
Duke Energy Carolinas
Debt Securities, Available-for-sale
Estimated Fair Value	1,480
Duke Energy Carolinas | NDTF
Cash and Cash Equivalents
Estimated Fair Value	81	51
Equity Securities, FV-NI
Gross Unrealized Holding Gains	3,226	2,886
Gross Unrealized Holding Losses	19	14
Estimated Fair Value	4,514	4,196
Debt Securities, Available-for-sale
Estimated Fair Value	1,480	1,438
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	3,232	2,904
Unrealized Holding Losses	114	99
Estimated Fair Value	6,075	5,685
Duke Energy Carolinas | Other Investments
Debt Securities, Available-for-sale
Estimated Fair Value	0
Progress Energy
Debt Securities, Available-for-sale
Estimated Fair Value	1,354
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,342	2,081
Unrealized Holding Losses	64	61
Estimated Fair Value	4,751	4,499
Progress Energy | NDTF
Cash and Cash Equivalents
Estimated Fair Value	59	82
Equity Securities, FV-NI
Gross Unrealized Holding Gains	2,327	2,056
Gross Unrealized Holding Losses	8	8
Estimated Fair Value	3,323	3,082
Debt Securities, Available-for-sale
Estimated Fair Value	1,330	1,294
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,342	2,081
Unrealized Holding Losses	64	60
Estimated Fair Value	4,712	4,458
Progress Energy | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	15	18
Debt Securities, Available-for-sale
Estimated Fair Value	24	23
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	0	0
Unrealized Holding Losses	0	1
Estimated Fair Value	39	41
Duke Energy Progress
Debt Securities, Available-for-sale
Estimated Fair Value	1,097
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,230	1,979
Unrealized Holding Losses	51	46
Estimated Fair Value	4,357	4,089
Duke Energy Progress | NDTF
Cash and Cash Equivalents
Estimated Fair Value	48	55
Equity Securities, FV-NI
Gross Unrealized Holding Gains	2,216	1,956
Gross Unrealized Holding Losses	8	8
Estimated Fair Value	3,200	2,970
Debt Securities, Available-for-sale
Estimated Fair Value	1,097	1,050
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	2,230	1,979
Unrealized Holding Losses	51	46
Estimated Fair Value	4,345	4,075
Duke Energy Progress | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	12	14
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	0	0
Unrealized Holding Losses	0	0
Estimated Fair Value	12	14
Duke Energy Florida
Debt Securities, Available-for-sale
Estimated Fair Value	257
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	112	102
Unrealized Holding Losses	13	15
Estimated Fair Value	393	409
Duke Energy Florida | NDTF
Cash and Cash Equivalents
Estimated Fair Value	11	27
Equity Securities, FV-NI
Gross Unrealized Holding Gains	111	100
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	123	112
Debt Securities, Available-for-sale
Estimated Fair Value	233	244
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	112	102
Unrealized Holding Losses	13	14
Estimated Fair Value	367	383
Duke Energy Florida | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	2	3
Debt Securities, Available-for-sale
Estimated Fair Value	24	23
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	0	0
Unrealized Holding Losses	0	1
Estimated Fair Value	26	26
Duke Energy Indiana
Debt Securities, Available-for-sale
Estimated Fair Value	63
Duke Energy Indiana | Other Investments
Cash and Cash Equivalents
Estimated Fair Value	1	1
Equity Securities, FV-NI
Gross Unrealized Holding Gains	13	4
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	108	98
Debt Securities, Available-for-sale
Estimated Fair Value	63	64
Investments, Accumulated Gross Unrealized Gains (Losses) [Abstract]
Unrealized Holding Gains	13	5
Unrealized Holding Losses	1	1
Estimated Fair Value	172	163
Corporate debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	8	12
Gross Unrealized Holding Losses	46	43
Estimated Fair Value	659	632
Corporate debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	6	6
Estimated Fair Value	87	82
Corporate debt securities | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	2	4
Gross Unrealized Holding Losses	37	35
Estimated Fair Value	397	390
Corporate debt securities | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	6	8
Gross Unrealized Holding Losses	9	8
Estimated Fair Value	262	242
Corporate debt securities | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	5	7
Gross Unrealized Holding Losses	9	8
Estimated Fair Value	248	229
Corporate debt securities | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	1	1
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	14	13
Corporate debt securities | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	8	8
Municipal bonds | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	6
Gross Unrealized Holding Losses	16	16
Estimated Fair Value	332	347
Municipal bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	1	2
Estimated Fair Value	79	77
Municipal bonds | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	4	4
Estimated Fair Value	38	50
Municipal bonds | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	6
Gross Unrealized Holding Losses	12	12
Estimated Fair Value	294	297
Municipal bonds | Progress Energy | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	24	23
Municipal bonds | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	6
Gross Unrealized Holding Losses	12	12
Estimated Fair Value	294	297
Municipal bonds | Duke Energy Florida | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	1
Estimated Fair Value	24	23
Municipal bonds | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	1	1
Estimated Fair Value	45	46
U.S. government bonds | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	9	24
Gross Unrealized Holding Losses	76	65
Estimated Fair Value	1,610	1,575
U.S. government bonds | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	3	2
Estimated Fair Value	60	65
U.S. government bonds | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	4	13
Gross Unrealized Holding Losses	41	33
Estimated Fair Value	854	826
U.S. government bonds | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	5	11
Gross Unrealized Holding Losses	35	32
Estimated Fair Value	756	749
U.S. government bonds | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	5	10
Gross Unrealized Holding Losses	22	18
Estimated Fair Value	539	518
U.S. government bonds | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	13	14
Estimated Fair Value	217	231
U.S. government bonds | Duke Energy Indiana | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	10	10
Other debt securities | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	13	13
Estimated Fair Value	209	178
Other debt securities | Other Investments
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	3	2
Estimated Fair Value	45	47
Other debt securities | Duke Energy Carolinas | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	1
Gross Unrealized Holding Losses	13	13
Estimated Fair Value	191	172
Other debt securities | Progress Energy | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	18	6
Other debt securities | Duke Energy Progress | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	16	6
Other debt securities | Duke Energy Florida | NDTF
Debt Securities, Available-for-sale
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Estimated Fair Value	$ 2	$ 0

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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