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DERIVATIVE INSTRUMENTS - GAINS (LOSSES) AND NOTIONAL VOLUMES (Details) gal in Millions, MWh in Millions, MMBTU in Millions, $ in Millions | 3 Months Ended | 6 Months Ended
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Jun. 30, 2019 USD ($) MMBTU MWh gal | Jun. 30, 2018 USD ($) MMBTU MWh gal | Jun. 30, 2019 USD ($) MMBTU MWh gal | Jun. 30, 2018 USD ($) MMBTU MWh gal
Realized Gain (Loss) on Derivatives, Net |  |  |  |
Gains (Losses) | $ (0.1) | $ 1.9 | $ 1.7 | $ 0.9
Natural gas contracts |  |  |  |
Realized Gain (Loss) on Derivatives, Net |  |  |  |
Gains (Losses) | $ (3.1) | $ (2.3) | $ (3.6) | $ (7.5)
Notional Sales Volumes |  |  |  |
Notional sales volumes | MMBTU | 43.8 | 39.9 | 99.9 | 88.0
Petroleum products contracts |  |  |  |
Realized Gain (Loss) on Derivatives, Net |  |  |  |
Gains (Losses) | $ 0.0 | $ 0.3 | $ 0.0 | $ 0.8
Notional Sales Volumes |  |  |  |
Notional sales volumes (gallons) | gal | 0.0 | 1.7 | 0.0 | 3.8
FTRs |  |  |  |
Realized Gain (Loss) on Derivatives, Net |  |  |  |
Gains (Losses) | $ 3.0 | $ 3.9 | $ 5.3 | $ 7.6
Notional Sales Volumes |  |  |  |
Notional sales volumes | MWh | 8.0 | 6.8 | 16.1 | 15.0

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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