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DERIVATIVE INSTRUMENTS (Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value) (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Jan. 01, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | $ 190.8 | $ 49.5 | $ 37.9
Derivative liability | 5.8 |  | 2.0
Not Designated as Hedging Instrument [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | 190.6 |  | 37.9
Derivative liability | 5.7 |  | 1.7
Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | 186.0 |  | 37.9
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | 4.6 |  | 0.0
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Other Current Liabilities [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative liability | 5.7 |  | 1.7
Fair Value, Inputs, Level 3 [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | 190.6 |  | 37.9
Derivative liability | 5.7 |  | 1.7
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Derivative Financial Instruments, Assets [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative assets | 0.2 |  | 0.0
Fair Value, Inputs, Level 3 [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Current Liabilities [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative liability | 0.1 |  | 0.3
Fair Value, Inputs, Level 3 [Member] | Not Designated as Hedging Instrument [Member] | Customer Supply Agreement [Member] | Other Current Liabilities [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative liability | $ 0.0 |  | $ 0.0

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- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
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- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
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