Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 91	$ 100
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	8	9
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	47	49
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	5	4
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	42	45
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	28	32
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 8	$ 10