Derivatives and Hedging (Derivative Instruments That Contain Credit-Risk Related Contingent Features and Cash Collateral) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 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	$ 911	$ 525
Fair value of collateral already posted	276	135
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	76	205
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	161	30
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables
Derivative, collateral, right to reclaim cash - not offset against net derivative	115	122
Derivative, collateral, obligation to return cash - not offset against net derivative
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	13	168
Fair value of collateral already posted	2	10
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	11	158
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	2	10
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables
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	4	60
Fair value of collateral already posted
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	4	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	9	108
Fair value of collateral already posted	2	10
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	7	98
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	2	10
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables
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	911	355
Fair value of collateral already posted	266	125
Additional cash collateral or letters of credit in the event credit-risk-related contingent features were triggered	80	47
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables	158	19
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Receivables
Derivative, collateral, right to reclaim cash - not offset against net derivative	108	115
Derivative, collateral, obligation to return cash - not offset against net derivative
Duke Energy Indiana [Member]
Information Regarding Cash Collateral Under Master Netting Arrangements
Amounts offset against derivative positions on the net condensed Consolidated Balance Sheets, Payables
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
Derivative, collateral, obligation to return cash - not offset against net derivative