Employee Benefit Plans (Projected Benefit Obligations Reconciliation of Funded Status to Net Amount Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plan
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			$ 77
Pension Plan | Duke Energy Carolinas
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			7
Pension Plan | Progress Energy
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			57
Pension Plan | Duke Energy Progress
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			4
Pension Plan | Duke Energy Florida
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			53
Pension Plan | Duke Energy Ohio
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			2
Pension Plan | Duke Energy Indiana
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			2
Pension Plan | Piedmont
Change in Fair Value of Plan Assets [Rollforward]
Employer contributions			1
Pension Plan | Qualified Plan
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	$ 8,634	$ 8,321
Service cost	168	157	158
Interest cost	220	269	317
Actuarial gain	(200)	433
Benefits paid	(615)	(541)
Benefits paid – settlements		(5)
Obligation at measurement date	8,207	8,634	8,321
Accumulated Benefit Obligation at measurement date	8,144	8,577
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	9,337	8,910
Actual return on plan assets	513	973
Benefits paid	(615)	(541)
Benefits paid – settlements		(5)
Plan assets at measurement date	9,235	9,337	8,910
Funded status of plan	1,028	703
Pension Plan | Qualified Plan | Duke Energy Carolinas
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,988	1,923
Service cost	54	49	49
Interest cost	51	62	75
Actuarial gain	(42)	83
Benefits paid	(148)	(137)
Transfers		8
Obligation at measurement date	1,903	1,988	1,923
Accumulated Benefit Obligation at measurement date	1,904	1,989
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	2,381	2,263
Actual return on plan assets	132	247
Benefits paid	(148)	(137)
Transfers		8
Plan assets at measurement date	2,365	2,381	2,263
Funded status of plan	462	393
Pension Plan | Qualified Plan | Progress Energy
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	2,715	2,608
Service cost	48	46	46
Interest cost	70	85	100
Actuarial gain	(108)	144
Benefits paid	(161)	(160)
Transfers	(4)	(8)
Obligation at measurement date	2,560	2,715	2,608
Accumulated Benefit Obligation at measurement date	2,529	2,684
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	3,049	2,898
Actual return on plan assets	169	319
Benefits paid	(161)	(160)
Transfers	(4)	(8)
Plan assets at measurement date	3,053	3,049	2,898
Funded status of plan	493	334
Pension Plan | Qualified Plan | Duke Energy Progress
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,193	1,170
Service cost	28	26	26
Interest cost	30	38	45
Actuarial gain	(18)	50
Benefits paid	(80)	(83)
Transfers		(8)
Obligation at measurement date	1,153	1,193	1,170
Accumulated Benefit Obligation at measurement date	1,154	1,194
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,422	1,364
Actual return on plan assets	79	149
Benefits paid	(80)	(83)
Transfers		(8)
Plan assets at measurement date	1,421	1,422	1,364
Funded status of plan	268	229
Pension Plan | Qualified Plan | Duke Energy Florida
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,507	1,424
Service cost	20	20	20
Interest cost	39	46	54
Actuarial gain	(89)	93
Benefits paid	(81)	(76)
Transfers	(4)
Obligation at measurement date	1,392	1,507	1,424
Accumulated Benefit Obligation at measurement date	1,361	1,476
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,605	1,515
Actual return on plan assets	90	166
Benefits paid	(81)	(76)
Transfers	(4)
Plan assets at measurement date	1,610	1,605	1,515
Funded status of plan	218	98
Pension Plan | Qualified Plan | Duke Energy Ohio
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	502	481
Service cost	5	4	4
Interest cost	13	15	18
Actuarial gain	(10)	21
Benefits paid	(50)	(34)
Transfers	(10)	15
Obligation at measurement date	450	502	481
Accumulated Benefit Obligation at measurement date	439	493
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	472	443
Actual return on plan assets	26	48
Benefits paid	(50)	(34)
Transfers	(10)	15
Plan assets at measurement date	438	472	443
Funded status of plan	(12)	(30)
Pension Plan | Qualified Plan | Duke Energy Indiana
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	715	693
Service cost	9	8	9
Interest cost	18	22	26
Actuarial gain	(10)	46
Benefits paid	(52)	(49)
Benefits paid – settlements		(5)
Obligation at measurement date	680	715	693
Accumulated Benefit Obligation at measurement date	672	709
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	684	667
Actual return on plan assets	37	71
Benefits paid	(52)	(49)
Benefits paid – settlements		(5)
Plan assets at measurement date	669	684	667
Funded status of plan	(11)	(31)
Pension Plan | Qualified Plan | Piedmont
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	293	292
Service cost	6	5	5
Interest cost	7	9	10
Actuarial gain	(5)	14
Benefits paid	(28)	(27)
Obligation at measurement date	273	293	292
Accumulated Benefit Obligation at measurement date	274	294
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	343	335
Actual return on plan assets	19	35
Benefits paid	(28)	(27)
Plan assets at measurement date	334	343	335
Funded status of plan	61	50
Other Post-Retirement Benefit Plans
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	709	723
Service cost	4	4	4
Interest cost	18	23	30
Plan participants' contributions	14	15
Actuarial gain	(47)	19
Benefits paid	(73)	(75)
Obligation at measurement date	625	709	723
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	237	220
Employer contributions	18
Actual return on plan assets	15	24
Benefits paid	(73)	(75)
Plan participants' contributions	14	15
Employer contributions		53
Plan assets at measurement date	211	237	220
Funded status of plan	(414)	(472)
Other Post-Retirement Benefit Plans | Duke Energy Carolinas
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	174	175
Service cost	1	1	1
Interest cost	4	5	7
Plan participants' contributions	3	3
Actuarial gain	(14)	8
Benefits paid	(19)	(18)
Obligation at measurement date	149	174	175
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	139	130
Employer contributions	3
Actual return on plan assets	9	14
Benefits paid	(19)	(18)
Plan participants' contributions	3	3
Employer contributions		10
Plan assets at measurement date	135	139	130
Funded status of plan	(14)	(35)
Other Post-Retirement Benefit Plans | Progress Energy
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	299	303
Service cost	1	1	1
Interest cost	7	10	12
Plan participants' contributions	5	5
Actuarial gain	(20)	8
Benefits paid	(29)	(28)
Obligation at measurement date	263	299	303
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(1)	(1)
Employer contributions	24
Benefits paid	(29)	(28)
Plan participants' contributions	5	5
Employer contributions		23
Plan assets at measurement date	(1)	(1)	(1)
Funded status of plan	(264)	(300)
Other Post-Retirement Benefit Plans | Duke Energy Progress
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	166	168
Interest cost	4	5	7
Plan participants' contributions	3	3
Actuarial gain	(10)	5
Benefits paid	(16)	(15)
Obligation at measurement date	147	166	168
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(2)	(1)
Employer contributions	13
Benefits paid	(16)	(15)
Plan participants' contributions	3	3
Employer contributions		11
Plan assets at measurement date	(2)	(2)	(1)
Funded status of plan	(149)	(168)
Other Post-Retirement Benefit Plans | Duke Energy Florida
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	130	135
Service cost			1
Interest cost	3	4	5
Plan participants' contributions	2	2
Actuarial gain	(10)	2
Benefits paid	(13)	(13)
Obligation at measurement date	112	130	135
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	(1)
Employer contributions	10
Benefits paid	(13)	(13)
Plan participants' contributions	2	2
Employer contributions		10
Plan assets at measurement date	(2)	(1)
Funded status of plan	(114)	(131)
Other Post-Retirement Benefit Plans | Duke Energy Ohio
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	27	29
Interest cost	1	1	1
Plan participants' contributions	1	1
Actuarial gain	(1)
Benefits paid	(3)	(4)
Obligation at measurement date	25	27	29
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	9	9
Employer contributions	1
Actual return on plan assets	1
Benefits paid	(3)	(4)
Plan participants' contributions	1	1
Employer contributions		3
Plan assets at measurement date	9	9	9
Funded status of plan	(16)	(18)
Other Post-Retirement Benefit Plans | Duke Energy Indiana
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	61	64
Service cost	1	1	1
Interest cost	1	2	3
Plan participants' contributions	2	2
Actuarial gain	(2)	1
Benefits paid	(9)	(9)
Obligation at measurement date	54	61	64
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	7	5
Employer contributions	6
Actual return on plan assets		1
Benefits paid	(9)	(9)
Plan participants' contributions	2	2
Employer contributions		8
Plan assets at measurement date	6	7	5
Funded status of plan	(48)	(54)
Other Post-Retirement Benefit Plans | Piedmont
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	30	30
Interest cost	1	1	1
Actuarial gain	(2)	1
Benefits paid	(2)	(2)
Obligation at measurement date	27	30	30
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	37	34
Employer contributions	1
Actual return on plan assets	3	4
Benefits paid	(2)	(2)
Employer contributions		1
Plan assets at measurement date	39	37	$ 34
Funded status of plan	$ 12	$ 7