Related Party Transactions (Other Revenue and Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Duke Energy Carolinas [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 831	$ 914	$ 851
Duke Energy Carolinas [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	22	24	21
Duke Energy Carolinas [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	38	51	133
Related party transaction, expenses from transactions with related party	156	183	198
Progress Energy [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	710	712	732
Progress Energy [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	35	38	33
Progress Energy [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	156	183	198
Related party transaction, expenses from transactions with related party	38	51	133
Progress Energy [Member] | Intercompany Natural Gas Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19
Duke Energy Progress [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	397	403	386
Duke Energy Progress [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	14	16	17
Duke Energy Progress [Member] | Joint Dispatch Agreement (JDA) [Member]
Related Party Transaction [Line Items]
Related party transaction, other revenues from transactions with related party	156	183	198
Related party transaction, expenses from transactions with related party	38	51	133
Duke Energy Progress [Member] | Intercompany Natural Gas Expense [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	19
Duke Energy Florida [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	313	309	346
Duke Energy Florida [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	21	22	16
Duke Energy Ohio [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	356	342	316
Duke Energy Ohio [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	5	6	13
Duke Energy Indiana [Member] | Corporate Governance And Shared Service Expenses [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	366	349	384
Duke Energy Indiana [Member] | Indemnification Coverages [Member]
Related Party Transaction [Line Items]
Related party transaction, expenses from transactions with related party	$ 8	$ 9	$ 11