Commitments and Contingencies (Schedule of Environmental Loss Contingencies) (Details) - Environmental reserves - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	$ 88	$ 75
Duke Energy Carolinas
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	19	19
Progress Energy
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	23	19
Duke Energy Progress
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	11	6
Duke Energy Florida
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	11	12
Duke Energy Ohio
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	34	22
Duke Energy Indiana
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	4	6
Piedmont
Loss Contingencies [Line Items]
Reserves for Environmental Remediation	$ 9	$ 10