Risk Management, Derivative Instruments and Hedging Activities (Notional Amounts of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013 GWh dth		Dec. 31, 2012 GWh dth
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	$ 1,224		$ 1,587
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	63,264		52,104
Natural gas (millions of decatherms)	536,000,000		528,000,000
Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	34		290
Cash Flow Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	1,190	[1]	1,047	[1]
Non-Recourse Debt	602		620
Fair Value Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			250
Duke Energy Carolinas [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	1,305		2,028
Progress Energy [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			50
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	925		1,850
Natural gas (millions of decatherms)	336,000,000		348,000,000
Progress Energy [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			50
Duke Energy Progress [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			50
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	925		1,850
Natural gas (millions of decatherms)	129,000,000		118,000,000
Duke Energy Progress [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			50
Duke Energy Florida [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Natural gas (millions of decatherms)	207,000,000		230,000,000
Duke Energy Ohio [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	27		277
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	59,662	[2]	51,215	[2]
Natural gas (millions of decatherms)	200,000,000		180,000,000
Duke Energy Ohio [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	27		27
Duke Energy Ohio [Member] | Fair Value Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			250
Duke Energy Indiana [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			200
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	702		97
Duke Energy Indiana [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount			$ 200

[1] Duke Energy includes amounts related to non-recourse variable rate long-term debt of VIEs of $602 million and $620 million at September 30, 2013, and at December 31, 2012, respectively.

[2] Amounts at Duke Energy Ohio include intercompany positions that eliminate at Duke Energy.