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Derivatives Net Gain (Loss) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Derivative [Line Items] |  |  |  |
Derivative, (loss) gain on derivative, net | $ 10.3 | $ 0.8 | $ 10.7 | $ 2.8
Commodity Contract [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative, (loss) gain on derivative, net | 10.6 | 1.0 | 11.2 | 3.0
Commodity Contract [Member] | Glencore [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative, (loss) gain on derivative, net | 1.9 | 0.0 | 2.7 | (0.1)
Foreign Exchange Contract [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative, (loss) gain on derivative, net | $ (0.3) | $ (0.2) | $ (0.5) | $ (0.2)

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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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