|
Risk Management Activities (Location And Fair Value Of Derivative Instruments On Consolidated Balance Sheets) (Details) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2013
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Dec. 31, 2012
|
|---|---|---|
| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | $ 73.5 | $ 148.2 |
| Total Liability Derivatives | 52.5 | 115.5 |
|
Designated As Hedging Instruments [Member] | Interest Rate Risk Activities [Member]
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| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 30.9 | 40.4 |
|
Designated As Hedging Instruments [Member] | Interest Rate Risk Activities [Member] | Price Risk Management Assets (Current) [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 0 | 0 |
|
Designated As Hedging Instruments [Member] | Interest Rate Risk Activities [Member] | Price Risk Management Assets (Noncurrent) [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 30.9 | 40.4 |
|
Designated As Hedging Instruments [Member] | Commodity Price Risk Programs [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Liability Derivatives | 0 | 0.1 |
|
Designated As Hedging Instruments [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Liabilities (Current) [Member]
|
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| Derivatives, Fair Value [Line Items] | ||
| Total Liability Derivatives | 0 | 0.1 |
|
Designated As Hedging Instruments [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Liabilities (Noncurrent) [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Liability Derivatives | 0 | 0 |
|
Not Designated as Hedging Instrument [Member] | Commodity Price Risk Programs [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 42.6 | 107.8 |
| Total Liability Derivatives | 52.5 | 115.4 |
|
Not Designated as Hedging Instrument [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Assets (Current) [Member]
|
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| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 39.6 | 92.2 |
|
Not Designated as Hedging Instrument [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Assets (Noncurrent) [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Asset Derivatives | 3.0 | 15.6 |
|
Not Designated as Hedging Instrument [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Liabilities (Current) [Member]
|
||
| Derivatives, Fair Value [Line Items] | ||
| Total Liability Derivatives | 47.5 | 95.1 |
|
Not Designated as Hedging Instrument [Member] | Commodity Price Risk Programs [Member] | Price Risk Management Liabilities (Noncurrent) [Member]
|
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| Derivatives, Fair Value [Line Items] | ||
| Total Liability Derivatives | $ 5.0 | $ 20.3 |