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