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Forward Equity (Details) (Forward Equity Sales, USD $) In Millions, unless otherwise specified | Sep. 30, 2014 | Dec. 31, 2013 | Dec. 31, 2012
--- | --- | --- | ---
Derivative |  |  |
Notional amount | $ 70.2 | $ 77.0 | $ 147.2
Average forward price | 198.71 | 185.56 | 121.37
Remaining notional amount | 252.8 |  |
Maximum |  |  |
Derivative |  |  |
Notional amount | $ 400.0 |  |

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- Definition Derivative, Remaining Notional Amount + References No definition available. + Details
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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References 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 The average forward price on the group of price risk forward or futures contracts, such as gas futures contracts. + References No definition available. + Details
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- Details
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