Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015 GWh	Dec. 31, 2014 GWh
Commodity Contracts [Member] \| Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	22,810	25,370
Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	666,000,000	676,000,000
Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	1,277	1,027
Duke Energy Carolinas [Member] \| Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	57,000,000	35,000,000
Progress Energy [Member] \| Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	333,000,000	328,000,000
Duke Energy Progress [Member] \| Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	111,000,000	116,000,000
Duke Energy Progress [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250
Duke Energy Florida [Member] \| Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	222,000,000	212,000,000
Duke Energy Florida [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	250
Duke Energy Ohio [Member] \| Commodity Contracts [Member] \| Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	17,734	19,141
Duke Energy Ohio [Member] \| Commodity Contracts [Member] \| Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume, in millions of decatherms	276,000,000	313,000,000
Duke Energy Ohio [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27
Duke Energy Indiana [Member] \| Commodity Contracts [Member] \| Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours	571
Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	750	750
Not Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	527	277
Not Designated as Hedging Instrument [Member] \| Duke Energy Progress [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Floating interest rate	1.75%
Notional amount	250
Not Designated as Hedging Instrument [Member] \| Duke Energy Florida [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	250	250
Not Designated as Hedging Instrument [Member] \| Duke Energy Ohio [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	27	27
Variable Interest Entity, Primary Beneficiary [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contracts [Member]
Derivative [Line Items]
Notional amount	541	541

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

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- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

No definition available.

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

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- Definition

Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

+ References

No definition available.

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