Commitments and Contingencies (Schedule of Reserves) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Reserves for legal matters	$ 197	$ 204
Progress Energy [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	73	78
Duke Energy Progress [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	10	10
Duke Energy Florida [Member]
Loss Contingencies [Line Items]
Reserves for legal matters	$ 42	$ 43