|
Derivatives and Hedging (Interest Rate Risk) (Details) (Interest Rate Contracts [Member], USD $)
In Millions, unless otherwise specified |
Sep. 30, 2014
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Dec. 31, 2013
|
|---|---|---|
| Derivative [Line Items] | ||
| Notional amount | $ 791 | $ 832 |
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Cash Flow Hedging [Member]
|
||
| Derivative [Line Items] | ||
| Notional amount | 764 | 798 |
|
Duke Energy Ohio [Member]
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| Derivative [Line Items] | ||
| Notional amount | 27 | 27 |
|
Duke Energy Ohio [Member] | Cash Flow Hedging [Member]
|
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| Derivative [Line Items] | ||
| Notional amount | ||
|
Not Designated as Hedging Instrument [Member]
|
||
| Derivative [Line Items] | ||
| Notional amount | 27 | 34 |
|
Not Designated as Hedging Instrument [Member] | Duke Energy Ohio [Member]
|
||
| Derivative [Line Items] | ||
| Notional amount | 27 | 27 |
|
Variable Interest Entity, Primary Beneficiary [Member] | Cash Flow Hedging [Member]
|
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| Derivative [Line Items] | ||
| Notional amount | $ 552 | $ 584 |