Fair Value Measurements (Fair Value Measurement Amounts for Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	$ 3,191
Derivative assets	320	$ 61
Total assets	11,213	9,748
Derivative liabilities	(472)	(324)
Net assets (liabilities)	10,741	9,424
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	1
Total assets	8,667	7,551
Derivative liabilities	(13)
Net assets (liabilities)	8,654	7,551
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	293	53
Total assets	2,472	2,144
Derivative liabilities	(314)	(240)
Net assets (liabilities)	2,158	1,904
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	24	7
Total assets	24	7
Derivative liabilities	(145)	(84)
Net assets (liabilities)	(121)	(77)
Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	50	46
Net assets (liabilities)	50	46
NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	160	177
Equity securities, FV-NI	7,350	6,235
Debt securities, available-for-sale	2,891	2,717
NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	160	177
Debt securities, available-for-sale	967	874
NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,924	1,843
NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	7,350	6,235
NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	7,300	6,189
NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	50	46
Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	156	146
Debt securities, available-for-sale	300	285
Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	156	146
Debt securities, available-for-sale	45	37
Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	255	248
Other cash and cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	36	127
Other cash and cash equivalents | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	36	127
Duke Energy Carolinas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,441
Derivative assets	162	20
Total assets	5,921	4,985
Derivative liabilities	(35)	(20)
Net assets (liabilities)	5,886	4,965
Duke Energy Carolinas | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	4,607	3,861
Net assets (liabilities)	4,607	3,861
Duke Energy Carolinas | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	162	20
Total assets	1,264	1,078
Derivative liabilities	(35)	(20)
Net assets (liabilities)	1,229	1,058
Duke Energy Carolinas | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	50	46
Net assets (liabilities)	50	46
Duke Energy Carolinas | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	53	30
Equity securities, FV-NI	4,265	3,685
Debt securities, available-for-sale	1,441	1,250
Duke Energy Carolinas | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	53	30
Equity securities, FV-NI		3,639
Debt securities, available-for-sale	339	192
Duke Energy Carolinas | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,102	1,058
Duke Energy Carolinas | NDTF | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI		46
Duke Energy Carolinas | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	4,265
Duke Energy Carolinas | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	4,215
Duke Energy Carolinas | NDTF equity securities | Not Categorized
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	50
Progress Energy
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,476
Derivative assets	124	33
Total assets	4,812	4,329
Derivative liabilities	(24)	(29)
Net assets (liabilities)	4,788	4,300
Progress Energy | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3,840	3,485
Net assets (liabilities)	3,840	3,485
Progress Energy | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	124	33
Total assets	972	844
Derivative liabilities	(24)	(29)
Net assets (liabilities)	948	815
Progress Energy | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	107	147
Equity securities, FV-NI	3,085	2,550
Debt securities, available-for-sale	1,450	1,467
Progress Energy | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	107	147
Debt securities, available-for-sale	628	682
Progress Energy | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	822	785
Progress Energy | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,085	2,550
Progress Energy | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	3,085	2,550
Progress Energy | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	26	26
Progress Energy | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	26	26
Progress Energy | Other cash and cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	20	106
Progress Energy | Other cash and cash equivalents | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	20	106
Duke Energy Progress
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	1,025
Derivative assets	124	33
Total assets	4,229	3,562
Derivative liabilities	(10)	(14)
Net assets (liabilities)	4,219	3,548
Duke Energy Progress | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	3,369	2,773
Net assets (liabilities)	3,369	2,773
Duke Energy Progress | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	124	33
Total assets	860	789
Derivative liabilities	(10)	(14)
Net assets (liabilities)	850	775
Duke Energy Progress | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	94	76
Equity securities, FV-NI	2,970	2,459
Debt securities, available-for-sale	1,025	993
Duke Energy Progress | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	94	76
Debt securities, available-for-sale	289	237
Duke Energy Progress | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	736	756
Duke Energy Progress | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,970	2,459
Duke Energy Progress | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	2,970	2,459
Duke Energy Progress | Other cash and cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	16	1
Duke Energy Progress | Other cash and cash equivalents | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	16	1
Duke Energy Florida
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	451
Total assets	582	663
Derivative liabilities	(14)
Net assets (liabilities)	568	663
Duke Energy Florida | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	470	608
Net assets (liabilities)	470	608
Duke Energy Florida | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	112	55
Derivative liabilities	(14)
Net assets (liabilities)	98	55
Duke Energy Florida | NDTF
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	13	71
Equity securities, FV-NI	115	91
Debt securities, available-for-sale	425	474
Duke Energy Florida | NDTF | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	13	71
Debt securities, available-for-sale	339	445
Duke Energy Florida | NDTF | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	86	29
Duke Energy Florida | NDTF equity securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	115	91
Duke Energy Florida | NDTF equity securities | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	115	91
Duke Energy Florida | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	26	26
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 Florida | Other cash and cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3	1
Duke Energy Florida | Other cash and cash equivalents | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	3	1
Duke Energy Indiana
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	64
Derivative assets	23	6
Total assets	184	149
Derivative liabilities	(27)	(1)
Net assets (liabilities)	157	148
Duke Energy Indiana | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	1
Total assets	98	98
Derivative liabilities	(13)	(1)
Net assets (liabilities)	85	97
Duke Energy Indiana | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	64	45
Derivative liabilities	(14)
Net assets (liabilities)	50	45
Duke Energy Indiana | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	22	6
Total assets	22	6
Net assets (liabilities)	22	6
Duke Energy Indiana | Other Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	97	97
Debt securities, available-for-sale	64	45
Duke Energy Indiana | Other Investments | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity securities, FV-NI	97	97
Duke Energy Indiana | Other Investments | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available-for-sale	64	45
Duke Energy Indiana | Other cash and cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		1
Duke Energy Indiana | Other cash and cash equivalents | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents		1
Piedmont
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	1
Derivative liabilities	(139)	(122)
Net assets (liabilities)	(136)	(121)
Piedmont | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	3	1
Net assets (liabilities)	3	1
Piedmont | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(139)
Net assets (liabilities)	$ (139)
Piedmont | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities		(122)
Net assets (liabilities)		$ (122)