Variable Interest Entities (Schedule of Accounts Receivable Securitizations) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Variable Interest Entities [Line Items]
Long-Term Debt	$ 46,043	$ 45,576
Duke Energy Carolinas [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	8,520	9,187
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	6,407	6,409
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Long-Term Debt	$ 6,160	5,799
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Line of Credit Facility, Expiration Date	Dec. 01, 2018
Facility size	$ 325
Long-Term Debt	$ 325	325
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, 2018
Facility size	$ 425
Long-Term Debt	$ 425	425
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, 2019
Facility size	$ 300
Long-Term Debt	$ 297	300
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, 2019
Facility size	$ 225
Long-Term Debt	$ 225	$ 225