Severance (Rollforward) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 41
Provision/adjustments	1
Cash reductions	(31)
Balance, end of period	11
Duke Energy Carolinas
Restructuring Reserve [Roll Forward]
Balance, beginning of period	11
Cash reductions	(9)
Balance, end of period	2
Progress Energy
Restructuring Reserve [Roll Forward]
Balance, beginning of period	13
Cash reductions	(10)
Balance, end of period	3
Duke Energy Progress
Restructuring Reserve [Roll Forward]
Balance, beginning of period	6
Provision/adjustments	(2)
Cash reductions	(3)
Balance, end of period	1
Duke Energy Florida
Restructuring Reserve [Roll Forward]
Balance, beginning of period	7
Provision/adjustments	2
Cash reductions	(7)
Balance, end of period	2
Duke Energy Ohio
Restructuring Reserve [Roll Forward]
Balance, beginning of period	1
Provision/adjustments	(1)
Duke Energy Indiana
Restructuring Reserve [Roll Forward]
Balance, beginning of period	2
Cash reductions	(1)
Balance, end of period	$ 1