Summary of Significant Accounting Policies (Other Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current Liabilities
Organization And Basis Of Presentation [Line Items]
Other accrued liabilities	$ 1,455	$ 604
Accrued compensation	662	862
Duke Energy Carolinas \| Current Liabilities
Organization And Basis Of Presentation [Line Items]
Other accrued liabilities	178	147
Accrued compensation	213	271
Progress Energy \| Current Liabilities
Organization And Basis Of Presentation [Line Items]
Customer deposits	347	354
Duke Energy Florida \| Current Liabilities
Organization And Basis Of Presentation [Line Items]
Customer deposits	203	209
Duke Energy Ohio \| Current Assets
Organization And Basis Of Presentation [Line Items]
Gas Storage	21	0
Duke Energy Indiana \| Current Assets
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	$ 9	$ 44

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