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DERIVATIVE INSTRUMENTS (Schedule Of Derivatives Not Designated As Hedging Instruments) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Revenues | $ 555.6 | $ 741.8 | $ 1,455.8 | $ 1,636.1
Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Revenues | (40.9) | 135.9 | 43.4 | 334.4
Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Revenue from Contract with Customer Benchmark [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of gain/(loss) recognized in income on derivative | 7.6 | 139.7 | 82.2 | 337.1
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Revenue from Contract with Customer Benchmark [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of gain/(loss) recognized in income on derivative | $ (48.5) | $ (3.8) | $ (38.8) | $ (2.7)

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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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