Variable Interest Entities (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2014
Variable Interest Entities [Line Items]
Debt instrument, face amount	$ 2,093,000,000
Cinergy Receivables [Member]
Variable Interest Entities [Line Items]
Line of credit facility, expiration date	Nov. 01, 2016
Minimum equity balance required by Cinergy Receivables	3,000,000
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Ownership interest in OVEC	9.00%
Duke Energy Carolinas [Member] | DERF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt instrument, face amount	400,000,000
Line of credit facility, expiration date	Oct. 01, 2016
Duke Energy Progress [Member]
Variable Interest Entities [Line Items]
Debt instrument, face amount	650,000,000
Duke Energy Progress [Member] | DEPR [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt instrument, face amount	300,000,000
Line of credit facility, expiration date	Dec. 01, 2016
Duke Energy Florida [Member]
Variable Interest Entities [Line Items]
Debt instrument, face amount	225,000,000
Duke Energy Florida [Member] | DEFR [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt instrument, face amount	$ 225,000,000
Line of credit facility, expiration date	Mar. 01, 2017
Duke Energy Indiana [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Variable Interest Entities [Line Items]
Fixed interest rate added to LIBOR to compute variable rate	1.00%