Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 3,081
Derivative assets	255	$ 189
Total assets	11,507	10,792
Derivative liabilities	(612)	(729)
Net assets (liabilities)	10,895	10,063
NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	140	133
Estimated Fair Value	7,837	7,278
Debt securities, available-for-sale	2,810	2,732
NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	7,837	7,278
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	21	31
Estimated Fair Value	173	158
Debt securities, available-for-sale	271	271
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	77	37
Total assets	9,136	8,484
Derivative liabilities	(51)	(60)
Net assets (liabilities)	9,085	8,424
Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	140	133
Debt securities, available-for-sale	873	829
Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	7,802	7,241
Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	21	31
Estimated Fair Value	173	158
Debt securities, available-for-sale	50	55
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	172	137
Total assets	2,330	2,256
Derivative liabilities	(561)	(669)
Net assets (liabilities)	1,769	1,587
Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	1,937	1,903
Level 2 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Debt securities, available-for-sale	221	216
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	6	15
Total assets	6	15
Derivative liabilities	0	0
Net assets (liabilities)	6	15
Level 3 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	0	0
Level 3 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Level 3 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Debt securities, available-for-sale	0	0
Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	35	37
Derivative liabilities	0	0
Net assets (liabilities)	35	37
Not Categorized | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	0	0
Not Categorized | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	35	37
Not Categorized | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Debt securities, available-for-sale	0	0
Duke Energy Carolinas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,480
Derivative assets	35	35
Total assets	6,110	5,720
Derivative liabilities	(234)	(260)
Net assets (liabilities)	5,876	5,460
Duke Energy Carolinas | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	81	51
Estimated Fair Value	4,514	4,196
Debt securities, available-for-sale	1,480	1,438
Duke Energy Carolinas | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	4,514	4,196
Duke Energy Carolinas | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	0
Duke Energy Carolinas | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	4,978	4,585
Derivative liabilities	0	0
Net assets (liabilities)	4,978	4,585
Duke Energy Carolinas | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	81	51
Debt securities, available-for-sale	418	375
Duke Energy Carolinas | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	4,479	4,159
Duke Energy Carolinas | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	0
Duke Energy Carolinas | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	35	35
Total assets	1,097	1,098
Derivative liabilities	(234)	(260)
Net assets (liabilities)	863	838
Duke Energy Carolinas | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	1,062	1,063
Duke Energy Carolinas | Level 2 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Duke Energy Carolinas | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	0
Duke Energy Carolinas | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	35	37
Derivative liabilities	0	0
Net assets (liabilities)	35	37
Duke Energy Carolinas | Not Categorized | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	0	0
Duke Energy Carolinas | Not Categorized | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	35	37
Duke Energy Carolinas | Not Categorized | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	0
Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,354
Derivative assets	57	34
Total assets	4,808	4,533
Derivative liabilities	(188)	(234)
Net assets (liabilities)	4,620	4,299
Progress Energy | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59	82
Estimated Fair Value	3,323	3,082
Debt securities, available-for-sale	1,330	1,294
Progress Energy | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,323	3,082
Progress Energy | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	15	18
Debt securities, available-for-sale	24	23
Progress Energy | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	3,852	3,636
Derivative liabilities	0	0
Net assets (liabilities)	3,852	3,636
Progress Energy | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59	82
Debt securities, available-for-sale	455	454
Progress Energy | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,323	3,082
Progress Energy | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	15	18
Debt securities, available-for-sale	0	0
Progress Energy | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	57	34
Total assets	956	897
Derivative liabilities	(188)	(234)
Net assets (liabilities)	768	663
Progress Energy | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	875	840
Progress Energy | Level 2 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Progress Energy | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	24	23
Duke Energy Progress
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,097
Derivative assets	47	32
Total assets	4,404	4,121
Derivative liabilities	(181)	(219)
Net assets (liabilities)	4,223	3,902
Duke Energy Progress | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	48	55
Estimated Fair Value	3,200	2,970
Debt securities, available-for-sale	1,097	1,050
Duke Energy Progress | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,200	2,970
Duke Energy Progress | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	12	14
Duke Energy Progress | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	3,540	3,305
Derivative liabilities	0	0
Net assets (liabilities)	3,540	3,305
Duke Energy Progress | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	48	55
Debt securities, available-for-sale	280	266
Duke Energy Progress | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,200	2,970
Duke Energy Progress | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	12	14
Duke Energy Progress | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	47	32
Total assets	864	816
Derivative liabilities	(181)	(219)
Net assets (liabilities)	683	597
Duke Energy Progress | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	817	784
Duke Energy Progress | Level 2 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Duke Energy Progress | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Duke Energy Florida
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	257
Derivative assets	10	2
Total assets	403	411
Derivative liabilities	(7)	(15)
Net assets (liabilities)	396	396
Duke Energy Florida | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	11	27
Estimated Fair Value	123	112
Debt securities, available-for-sale	233	244
Duke Energy Florida | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	123	112
Duke Energy Florida | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2	3
Debt securities, available-for-sale	24	23
Duke Energy Florida | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Total assets	311	330
Derivative liabilities	0	0
Net assets (liabilities)	311	330
Duke Energy Florida | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	11	27
Debt securities, available-for-sale	175	188
Duke Energy Florida | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	123	112
Duke Energy Florida | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2	3
Debt securities, available-for-sale	0	0
Duke Energy Florida | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	10	2
Total assets	92	81
Derivative liabilities	(7)	(15)
Net assets (liabilities)	85	66
Duke Energy Florida | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	58	56
Duke Energy Florida | Level 2 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	0	0
Duke Energy Florida | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Debt securities, available-for-sale	24	23
Duke Energy Indiana
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	63
Derivative assets	24	25
Total assets	196	188
Derivative liabilities	(19)	(18)
Net assets (liabilities)	177	170
Duke Energy Indiana | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1	1
Estimated Fair Value	108	98
Debt securities, available-for-sale	63	64
Duke Energy Indiana | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	5
Total assets	111	104
Derivative liabilities	(19)	(18)
Net assets (liabilities)	92	86
Duke Energy Indiana | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1	1
Estimated Fair Value	108	98
Debt securities, available-for-sale	0	0
Duke Energy Indiana | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	17	7
Total assets	80	71
Derivative liabilities	0	0
Net assets (liabilities)	80	71
Duke Energy Indiana | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Debt securities, available-for-sale	63	64
Duke Energy Indiana | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	5	13
Total assets	5	13
Derivative liabilities	0	0
Net assets (liabilities)	5	13
Duke Energy Indiana | Level 3 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Estimated Fair Value	0	0
Debt securities, available-for-sale	0	0
Piedmont
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1	1
Derivative liabilities	(126)	(147)
Net assets (liabilities)	(125)	(146)
Piedmont | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1	1
Derivative liabilities	0	0
Net assets (liabilities)	1	1
Piedmont | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	0	0
Derivative liabilities	(126)	(147)
Net assets (liabilities)	$ (126)	$ (147)