Summary of Significant Accounting Policies (Allowance for Doubtful Accounts)(Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	$ 14	$ 12	$ 14
Receivables of VIEs, allowance for doubtful accounts	54	53	51
Duke Energy Carolinas [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	3	3
Receivables of VIEs, allowance for doubtful accounts	7	7	6
Progress Energy [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	6	6	8
Receivables of VIEs, allowance for doubtful accounts	7	8	8
Duke Energy Progress [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	4	4	7
Receivables of VIEs, allowance for doubtful accounts	5	5	5
Duke Energy Florida [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	2	2
Receivables of VIEs, allowance for doubtful accounts	2	3	3
Duke Energy Ohio [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	2	2	2
Duke Energy Indiana [Member]
Organization And Basis Of Presentation [Line Items]
Receivables, allowance for doubtful accounts	$ 1	$ 1	$ 1