Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 710	$ 827
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	257	295
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	188	217
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	114	135
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	74	82
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	1
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	62	79
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	28	27
Duke Energy Indiana [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 91	$ 112