Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 2,824
Derivative assets	525	$ 795
Total assets	10,216	9,846
Derivative liabilities	(520)	(437)
Net assets (liabilities)	9,696	9,409
NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	160	215
Estimated Fair Value	6,530	5,871
Debt securities, available-for-sale	2,569	2,550
NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	6,530	5,871
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	36	22
Estimated Fair Value	141	128
Debt securities, available-for-sale	255	265
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	1
Total assets	7,625	7,030
Derivative liabilities	(4)	(16)
Net assets (liabilities)	7,621	7,014
Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	160	215
Debt securities, available-for-sale	755	780
Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	6,491	5,829
Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	36	22
Estimated Fair Value	141	128
Debt securities, available-for-sale	40	55
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	493	760
Total assets	2,522	2,740
Derivative liabilities	(516)	(421)
Net assets (liabilities)	2,006	2,319
Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,814	1,770
Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	215	210
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	30	34
Total assets	30	34
Net assets (liabilities)	30	34
Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	39	42
Net assets (liabilities)	39	42
Not Categorized | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	39	42
Duke Energy Carolinas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,329
Derivative assets	93	330
Total assets	5,248	5,112
Derivative liabilities	(204)	(127)
Net assets (liabilities)	5,044	4,985
Duke Energy Carolinas | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59	117
Estimated Fair Value	3,767	3,367
Debt securities, available-for-sale	1,329	1,298
Duke Energy Carolinas | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,767	3,367
Duke Energy Carolinas | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	4,107	3,765
Net assets (liabilities)	4,107	3,765
Duke Energy Carolinas | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59	117
Debt securities, available-for-sale	320	323
Duke Energy Carolinas | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	3,728	3,325
Duke Energy Carolinas | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	93	330
Total assets	1,102	1,305
Derivative liabilities	(204)	(127)
Net assets (liabilities)	898	1,178
Duke Energy Carolinas | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,009	975
Duke Energy Carolinas | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	39	42
Net assets (liabilities)	39	42
Duke Energy Carolinas | Not Categorized | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	39	42
Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,263
Derivative assets	196	248
Total assets	4,331	4,138
Derivative liabilities	(137)	(66)
Net assets (liabilities)	4,194	4,072
Progress Energy | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	101	98
Estimated Fair Value	2,763	2,504
Debt securities, available-for-sale	1,240	1,252
Progress Energy | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	2,763	2,504
Progress Energy | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	8	11
Debt securities, available-for-sale	23	25
Progress Energy | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3,307	3,070
Net assets (liabilities)	3,307	3,070
Progress Energy | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	101	98
Debt securities, available-for-sale	435	457
Progress Energy | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	2,763	2,504
Progress Energy | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	8	11
Progress Energy | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	196	248
Total assets	1,024	1,068
Derivative liabilities	(137)	(66)
Net assets (liabilities)	887	1,002
Progress Energy | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	805	795
Progress Energy | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	23	25
Duke Energy Progress
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	971
Derivative assets	79	230
Total assets	3,779	3,669
Derivative liabilities	(137)	(48)
Net assets (liabilities)	3,642	3,621
Duke Energy Progress | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	62	56
Estimated Fair Value	2,663	2,411
Debt securities, available-for-sale	971	963
Duke Energy Progress | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	2,663	2,411
Duke Energy Progress | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	4	9
Duke Energy Progress | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	2,955	2,701
Net assets (liabilities)	2,955	2,701
Duke Energy Progress | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	62	56
Debt securities, available-for-sale	226	225
Duke Energy Progress | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	2,663	2,411
Duke Energy Progress | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	4	9
Duke Energy Progress | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	79	230
Total assets	824	968
Derivative liabilities	(137)	(48)
Net assets (liabilities)	687	920
Duke Energy Progress | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	745	738
Duke Energy Florida
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	292
Derivative assets	117	17
Total assets	549	467
Derivative liabilities		(19)
Net assets (liabilities)	549	448
Duke Energy Florida | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	39	42
Estimated Fair Value	100	93
Debt securities, available-for-sale	269	289
Duke Energy Florida | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	100	93
Duke Energy Florida | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1	1
Debt securities, available-for-sale	23	25
Duke Energy Florida | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	349	368
Net assets (liabilities)	349	368
Duke Energy Florida | Level 1 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	39	42
Debt securities, available-for-sale	209	232
Duke Energy Florida | Level 1 | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	100	93
Duke Energy Florida | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1	1
Duke Energy Florida | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	117	17
Total assets	200	99
Derivative liabilities		(19)
Net assets (liabilities)	200	80
Duke Energy Florida | Level 2 | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	60	57
Duke Energy Florida | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	23	25
Duke Energy Indiana
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	59
Derivative assets	55	110
Total assets	205	250
Derivative liabilities	(4)	(16)
Net assets (liabilities)	201	234
Duke Energy Indiana | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3	1
Estimated Fair Value	88	79
Debt securities, available-for-sale	59	60
Duke Energy Indiana | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1
Total assets	92	80
Derivative liabilities	(4)	(16)
Net assets (liabilities)	88	64
Duke Energy Indiana | Level 1 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3	1
Estimated Fair Value	88	79
Duke Energy Indiana | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	27	81
Total assets	86	141
Net assets (liabilities)	86	141
Duke Energy Indiana | Level 2 | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	59	60
Duke Energy Indiana | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	27	29
Total assets	27	29
Net assets (liabilities)	27	29
Piedmont
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1
Derivative liabilities	(145)	(168)
Net assets (liabilities)	(144)	(168)
Piedmont | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1
Net assets (liabilities)	1
Piedmont | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(145)	(168)
Net assets (liabilities)	$ (145)	$ (168)