Risk Management, Derivative Instruments And Hedging Activities (Notional Amounts Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013 dth GWh		Dec. 31, 2012 GWh dth
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Cash flow hedges	$ 1,047	[1]	$ 1,047	[1]
Undesignated contracts	238		290
Fair value hedges	250		250
Total Notional Amount	1,535		1,587
Non-recourse Long-term debt of Variable Interest Entities	1,255		852
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	56,890		52,104
Natural gas (in decatherms)	516,000,000		528,000,000
Cash Flow Hedging [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Non-recourse Long-term debt of Variable Interest Entities	620		620
Duke Energy Carolinas [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Non-recourse Long-term debt of Variable Interest Entities	300		300
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	1,802		2,028
Progress Energy [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Undesignated contracts			50
Total Notional Amount			50
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	1,850		1,850
Natural gas (in decatherms)	335,000,000		348,000,000
Duke Energy Progress [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Undesignated contracts			50
Total Notional Amount			50
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	1,850		1,850
Natural gas (in decatherms)	110,000,000		118,000,000
Duke Energy Florida [Member]
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Natural gas (in decatherms)	225,000,000		230,000,000
Duke Energy Ohio [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Undesignated contracts	27		27
Fair value hedges	250		250
Total Notional Amount	277		277
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	53,173	[2]	51,215	[2]
Natural gas (in decatherms)	181,000,000		180,000,000
Duke Energy Indiana [Member]
Notional Amounts Of Derivative Instruments Related To Interest Rate Risk
Undesignated contracts	200		200
Total Notional Amount	$ 200		$ 200
Underlying Notional Amounts For Derivative Instruments Accounted For At Fair Value
Electricity-energy (Gigawatt-hours)	406		97

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

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