Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	$ 75	$ 58
Duke Energy Carolinas
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	19	11
Progress Energy
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	19	16
Duke Energy Progress
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	6	4
Duke Energy Florida
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	12	9
Duke Energy Ohio
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	22	19
Duke Energy Indiana
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	6	4
Piedmont
Disclosure Environmental Matters Details [Line Items]
Reserves for Environmental Remediation	10	$ 8
Environmental reserves
Disclosure Environmental Matters Details [Line Items]
Additional losses in excess of recorded reserves that could be incurred	25
Environmental reserves | Duke Energy Carolinas
Disclosure Environmental Matters Details [Line Items]
Additional losses in excess of recorded reserves that could be incurred	12
Environmental reserves | Duke Energy Ohio
Disclosure Environmental Matters Details [Line Items]
Additional losses in excess of recorded reserves that could be incurred	4
Environmental reserves | Piedmont
Disclosure Environmental Matters Details [Line Items]
Additional losses in excess of recorded reserves that could be incurred	$ 2