Derivatives and Hedging (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	$ 79	$ 44
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	79	44
Duke Energy Carolinas
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	35	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	35	19
Progress Energy
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	44	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	44	25
Duke Energy Progress
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value of derivatives in a net liability position	44	25
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	$ 44	$ 25