Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 821	$ 827
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	314	295
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	224	217
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	117	135
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	107	82
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	2
Duke Energy Ohio [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	67	79
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	30	27
Duke Energy Indiana [Member] | Cinergy Receivables [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 98	$ 112