Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 3,133
Derivative assets	1,108	$ 320
Total assets	11,479	11,213
Derivative liabilities	(433)	(472)
Net assets (liabilities)	11,046	10,741
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	27	3
Total assets	8,204	8,667
Derivative liabilities		(13)
Net assets (liabilities)	8,204	8,654
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1,071	293
Total assets	3,218	2,472
Derivative liabilities	(224)	(314)
Net assets (liabilities)	2,994	2,158
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	10	24
Total assets	10	24
Derivative liabilities	(209)	(145)
Net assets (liabilities)	(199)	(121)
Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	47	50
Net assets (liabilities)	47	50
NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	128	160
Equity securities, FV-NI	6,853	7,350
Debt securities, available-for-sale	2,845	2,891
NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	128	160
Debt securities, available-for-sale	947	967
NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,898	1,924
NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	6,853	7,350
NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	6,806	7,300
NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	47	50
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	110	36
Equity securities, FV-NI	147	156
Debt securities, available-for-sale	288	300
Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	110	36
Equity securities, FV-NI	147	156
Debt securities, available-for-sale	39	45
Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	249	255
Duke Energy Carolinas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,419
Derivative assets	493	162
Total assets	5,934	5,921
Derivative liabilities	(37)	(35)
Net assets (liabilities)	5,897	5,886
Duke Energy Carolinas | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	4,324	4,607
Net assets (liabilities)	4,324	4,607
Duke Energy Carolinas | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	493	162
Total assets	1,563	1,264
Derivative liabilities	(37)	(35)
Net assets (liabilities)	1,526	1,229
Duke Energy Carolinas | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	47	50
Net assets (liabilities)	47	50
Duke Energy Carolinas | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	60	53
Equity securities, FV-NI	3,962	4,265
Debt securities, available-for-sale	1,419	1,441
Duke Energy Carolinas | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	60	53
Debt securities, available-for-sale	349	339
Duke Energy Carolinas | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,070	1,102
Duke Energy Carolinas | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,962	4,265
Duke Energy Carolinas | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,915	4,215
Duke Energy Carolinas | NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	47	50
Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,452
Derivative assets	425	124
Total assets	4,853	4,812
Derivative liabilities		(24)
Net assets (liabilities)	4,853	4,788
Progress Energy | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Total assets	3,576	3,840
Net assets (liabilities)	3,576	3,840
Progress Energy | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	423	124
Total assets	1,277	972
Derivative liabilities		(24)
Net assets (liabilities)	1,277	948
Progress Energy | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	68	107
Equity securities, FV-NI	2,891	3,085
Debt securities, available-for-sale	1,426	1,450
Progress Energy | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	68	107
Debt securities, available-for-sale	598	628
Progress Energy | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	828	822
Progress Energy | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,891	3,085
Progress Energy | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,891	3,085
Progress Energy | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	17	20
Debt securities, available-for-sale	26	26
Progress Energy | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	17	20
Progress Energy | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	26	26
Duke Energy Progress
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,031
Derivative assets	385	124
Total assets	4,270	4,229
Derivative liabilities		(10)
Net assets (liabilities)	4,270	4,219
Duke Energy Progress | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2
Total assets	3,135	3,369
Net assets (liabilities)	3,135	3,369
Duke Energy Progress | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	383	124
Total assets	1,135	860
Derivative liabilities		(10)
Net assets (liabilities)	1,135	850
Duke Energy Progress | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	58	94
Equity securities, FV-NI	2,782	2,970
Debt securities, available-for-sale	1,031	1,025
Duke Energy Progress | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	58	94
Debt securities, available-for-sale	279	289
Duke Energy Progress | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	752	736
Duke Energy Progress | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,782	2,970
Duke Energy Progress | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,782	2,970
Duke Energy Progress | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	14	16
Duke Energy Progress | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	14	16
Duke Energy Florida
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	421
Derivative assets	40
Total assets	582	582
Derivative liabilities		(14)
Net assets (liabilities)	582	568
Duke Energy Florida | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	440	470
Net assets (liabilities)	440	470
Duke Energy Florida | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	40
Total assets	142	112
Derivative liabilities		(14)
Net assets (liabilities)	142	98
Duke Energy Florida | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10	13
Equity securities, FV-NI	109	115
Debt securities, available-for-sale	395	425
Duke Energy Florida | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10	13
Debt securities, available-for-sale	319	339
Duke Energy Florida | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	76	86
Duke Energy Florida | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	109	115
Duke Energy Florida | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	109	115
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	26	26
Duke Energy Florida | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	2	3
Duke Energy Florida | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	26	26
Duke Energy Indiana
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	63
Derivative assets	45	23
Total assets	200	184
Derivative liabilities		(27)
Net assets (liabilities)	200	157
Duke Energy Indiana | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	18	1
Total assets	110	98
Derivative liabilities		(13)
Net assets (liabilities)	110	85
Duke Energy Indiana | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	17
Total assets	80	64
Derivative liabilities		(14)
Net assets (liabilities)	80	50
Duke Energy Indiana | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	10	22
Total assets	10	22
Net assets (liabilities)	10	22
Duke Energy Indiana | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1
Equity securities, FV-NI	91	97
Debt securities, available-for-sale	63	64
Duke Energy Indiana | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1
Equity securities, FV-NI	91	97
Duke Energy Indiana | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	63	64
Piedmont
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7	3
Derivative liabilities	(173)	(139)
Net assets (liabilities)	(166)	(136)
Piedmont | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	7	3
Net assets (liabilities)	7	3
Piedmont | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(173)	(139)
Net assets (liabilities)	$ (173)	$ (139)