Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014 dth GWh		Dec. 31, 2013 dth GWh
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	66,268		71,466
Natural gas (millions of decatherms)	604,000,000		636,000,000
Interest Rate Contracts [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	$ 825		$ 832
Interest Rate Contracts [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	27		34
Interest Rate Contracts [Member] | Cash Flow Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	798	[1]	798	[1]
Interest Rate Contracts [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Cash Flow Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	584		584
Duke Energy Carolinas [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	1,028		1,205
Progress Energy [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	925		925
Natural gas (millions of decatherms)	352,000,000		363,000,000
Duke Energy Progress [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	925		925
Natural gas (millions of decatherms)	128,000,000		141,000,000
Duke Energy Florida [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Natural gas (millions of decatherms)	224,000,000		222,000,000
Duke Energy Ohio [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	60,115	[2]	69,362	[2]
Natural gas (millions of decatherms)	254,000,000		274,000,000
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	27		27
Duke Energy Ohio [Member] | Interest Rate Contracts [Member] | Nondesignated [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk [Abstract]
Derivative, Notional Amount	$ 27		$ 27
Duke Energy Indiana [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value [Abstract]
Electricity-energy (Gigawatt-hours)	272		203

[1] Duke Energy includes amounts related to non-recourse variable rate long-term debt of VIEs of $602 million and $620 million at March 31, 2014, and at December 31, 2013, respectively.

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