Organization and Basis of Presentation (Schedule of Unbilled Revenues with Restricted Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 800	$ 748
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	318	283
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	195	172
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	96	102
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	99	70
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	2	3
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	36	31
Cinergy Receivables [Member] | Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	72	71
Cinergy Receivables [Member] | Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Unbilled receivables	$ 109	$ 97