Risk Management, Derivative Instruments and Hedging Activities (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
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	$ 532	$ 466
Collateral aready posted	158	163
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	246	230
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables	39	73
Derivative, collateral, right to reclaim cash - not offset against net derivative	129	93
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	261	286
Collateral aready posted	32	59
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	229	227
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables	32	58
Derivative, collateral, right to reclaim cash - not offset against net derivative		1
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	97	108
Collateral aready posted	4	9
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	93	99
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables	4	9
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	164	178
Collateral aready posted	28	50
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	136	128
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables	28	49
Derivative, collateral, right to reclaim cash - not offset against net derivative		1
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	268	176
Collateral aready posted	126	104
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered at the end of the reporting period	17	2
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables	5	15
Derivative, collateral, right to reclaim cash - not offset against net derivative	120	92
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	2
Derivative, collateral, right to reclaim cash - not offset against net derivative	$ 9