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INVENTORIES (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Inventory [Line Items] |  |
Effect of LIFO Inventory Increment on Financial Position | $ 34.2 |
Effect of LIFO Inventory Liquidation on Income |  | $ (0.2)
Allowance for Obsolete and Surplus Items | 12.7 | 12.6
Mining and Pelletizing [Member] |  |
Inventory [Line Items] |  |
Inventory, LIFO Reserve | $ 101.3 | $ 95.6

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