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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, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | $ 41.2 | $ 11.6 | $ 89.7 | $ 49.7
Customer Supply Agreements [Member] | Product Revenues [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | 54.3 | 7.1 | 123.9 | 26.8
Provisional Pricing Arrangements [Member] | Product Revenues [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | (13.1) | 4.5 | (32.9) | 22.9
Commodity Contract [Member] | Other Nonoperating Income (Expense) [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net | $ 0.0 | $ 0.0 | $ (1.3) | $ 0.0

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- Definition Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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