Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 109	$ 101	$ 308	$ 416
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	9	4	27	93
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	67	63	174	214
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4		12	56
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	63	63	162	158
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	24	24	80	80
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 9	$ 10	$ 27	$ 29