Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - Qualified Pension Plans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 40	$ 44
Interest cost on projected benefit obligation	58	55
Expected return on plan assets	(140)	(139)
Amortization of actuarial loss	24	33
Amortization of prior service credit	(5)	(7)
Amortization of settlement charges	2	2
Net periodic pension costs	(21)	(12)
Duke Energy Carolinas
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	12	14
Interest cost on projected benefit obligation	14	13
Expected return on plan assets	(38)	(35)
Amortization of actuarial loss	5	7
Amortization of prior service credit	(1)	(2)
Amortization of settlement charges	1	1
Net periodic pension costs	(7)	(2)
Progress Energy
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	12	13
Interest cost on projected benefit obligation	18	17
Expected return on plan assets	(46)	(47)
Amortization of actuarial loss	6	10
Amortization of prior service credit		(1)
Amortization of settlement charges	1	1
Net periodic pension costs	(9)	(7)
Duke Energy Progress
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	7	7
Interest cost on projected benefit obligation	8	7
Expected return on plan assets	(22)	(21)
Amortization of actuarial loss	3	5
Net periodic pension costs	(4)	(2)
Duke Energy Florida
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	4	5
Interest cost on projected benefit obligation	10	10
Expected return on plan assets	(24)	(26)
Amortization of actuarial loss	3	5
Net periodic pension costs	(7)	(6)
Duke Energy Ohio
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1
Interest cost on projected benefit obligation	3	3
Expected return on plan assets	(5)	(7)
Amortization of actuarial loss	1	2
Net periodic pension costs		(1)
Duke Energy Indiana
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	2
Interest cost on projected benefit obligation	5	5
Expected return on plan assets	(9)	(10)
Amortization of actuarial loss	2	3
Piedmont
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	1	1
Interest cost on projected benefit obligation	2	2
Expected return on plan assets	(6)	(5)
Amortization of actuarial loss	2	2
Amortization of prior service credit	(2)	(1)
Net periodic pension costs	$ (3)	$ (1)