Variable Interest Entities (Fair Value Assumptions) (Details) - CRC - Non-consolidated VIEs	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Duke Energy Ohio
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.50%	0.60%
Discount rate	1.60%	3.30%
Receivable turnover rate	13.40%	13.40%
Duke Energy Indiana
Variable Interest Entity [Line Items]
Anticipated credit loss ratio	0.30%	0.30%
Discount rate	1.60%	3.30%
Receivable turnover rate	11.30%	11.50%