Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Variable Interest Entities [Line Items]
Long-Term Debt	$ 54,342	$ 51,123
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	10,208	10,633
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,893	7,451
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 6,542	7,051
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Dec. 01, 2020
Facility size	$ 350
Long-Term Debt	328	325
Accounts receivable from securitization	$ 484	564
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Dec. 01, 2020
Facility size	$ 475
Long-Term Debt	475	450
Accounts receivable from securitization	$ 671	699
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Feb. 01, 2021
Facility size	$ 325
Long-Term Debt	325	300
Accounts receivable from securitization	$ 518	547
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Apr. 01, 2021
Facility size	$ 250
Long-Term Debt	250	225
Accounts receivable from securitization	$ 472	$ 357