Variable Interest Entities (Schedule of Accounts Receivable Securitizations)(Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Debt instrument, face amount	$ 2,922,000,000	$ 4,023,000,000
Duke Energy Progress [Member]
Variable Interest Entity [Line Items]
Debt instrument, face amount	1,350,000,000	800,000,000
Duke Energy Florida [Member]
Variable Interest Entity [Line Items]
Debt instrument, face amount	225,000,000
DERF [Member] | Duke Energy Carolinas [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt instrument, face amount	400,000,000
Line of credit facility, expiration date	Oct. 01, 2016
DEPR [Member] | Duke Energy Progress [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt instrument, face amount	300,000,000
Line of credit facility, expiration date	Dec. 01, 2016
DEFR [Member] | Duke Energy Florida [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Debt instrument, face amount	$ 225,000,000
Line of credit facility, expiration date	Mar. 01, 2017