(Other Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	$ 729	$ 330
Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	793	757
Duke Energy Carolinas [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Accrued compensation	251	252
Progress Energy [Member] \| Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	66	278
Progress Energy [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	345	338
Duke Energy Progress [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	137	129
Accrued compensation	130	132
Duke Energy Florida [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	208	208
Accrued compensation	85	16
Duke Energy Ohio [Member] \| Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	13	36
Duke Energy Ohio [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	44	46
Duke Energy Indiana [Member] \| Current Liabilities, Other [Member]
Organization And Basis Of Presentation [Line Items]
Customer deposits	47	45
Piedmont Natural Gas [Member] \| Current Assets, Other [Member]
Organization And Basis Of Presentation [Line Items]
Income taxes receivable	$ 11	$ 43

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