Organization and Basis of Presentation (Schedule of Excise Taxes) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 100	$ 167
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	9	46
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	49	77
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	4	32
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	45	45
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	32	34
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Excise taxes collected	$ 10	$ 10