Inventories Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
LIFO inventory amount	$ 627.5	$ 776.1
Inventory valuation reserves	(126.9)	(104.1)
Effect of LIFO liquidation on income	(22.6)	(1.8)	$ 0.8
Inventories, net	997.1	1,155.3
Adjustment from current cost to LIFO cost basis	44.1	33.6
Net Realizable Value Reserve
Inventory [Line Items]
Inventory valuation reserves	$ (44.1)	$ (33.6)