Income Taxes (Effective Tax Rates) (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	31.90%	31.20%
Duke Energy Carolinas [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	35.80%	37.40%
Progress Energy [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	35.40%	36.90%
Duke Energy Progress [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	33.80%	36.60%
Duke Energy Florida [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	38.60%	38.50%
Duke Energy Ohio [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	36.70%	36.40%
Duke Energy Indiana [Member]
Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to the Actual Tax Expense from Continuing Operations [Abstract]
Effective tax rate	36.60%	36.80%