Derivatives and Hedging (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	$ 845	$ 525
Collateral already posted	209	135
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	407	205
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	145	30
Derivative, collateral, right to reclaim cash - not offset against net derivative	64	122
Duke Energy Carolinas [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	19
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	19
Progress Energy [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	370	168
Collateral already posted	23	10
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	347	158
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	23	10
Duke Energy Progress [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	131	60
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	131	60
Duke Energy Florida [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	239	108
Collateral already posted	23	10
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	216	98
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	23	10
Duke Energy Ohio [Member]
Schedule Of Information Regarding Derivative Instruments That Contain Credit-Risk Related Contingent Features
Aggregate fair value amounts of derivative instruments in a net liability position	456	355
Collateral already posted	186	125
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	41	47
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	122	19
Derivative, collateral, right to reclaim cash - not offset against net derivative	64	115
Duke Energy Indiana [Member]
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables		1
Derivative, collateral, right to reclaim cash - not offset against net derivative		$ 1