Commitments and Contingencies (Narrative) (Details) $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($) case claim plant	Dec. 31, 2020 USD ($)
Texas Storm Uri Tort Litigation
Loss Contingencies [Line Items]
Number of state court actions filed \| case	24
Number of pending federal court cases \| case	1
Coal Ash Insurance Coverage Litigation
Loss Contingencies [Line Items]
Number of NC and SC Plants with Ash Basins \| plant	15
Duke Energy Carolinas \| Asbestos-related Injuries and Damages Claims
Loss Contingencies [Line Items]
Asbestos-related injuries and damages reserves	$ 555	$ 572
Reinsurance retention policy, excess retention, amount reinsured	714
Probable insurance recoveries	$ 704	704
Duke Energy Carolinas \| Asbestos-related Injuries and Damages Claims \| Non-malignant cases
Loss Contingencies [Line Items]
Loss contingency, pending claims, number \| claim	84
Asbestos-related injuries and damages reserves	$ 18
Duke Energy Carolinas \| Asbestos-related Injuries and Damages Claims \| Malignant cases
Loss Contingencies [Line Items]
Loss contingency, pending claims, number \| claim	55
Asbestos-related injuries and damages reserves	$ 20
Duke Energy and Duke Energy Carolinas \| ASU 2016-13
Loss Contingencies [Line Items]
Reserve for credit losses for insurance receivables	$ 15	$ 15

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