Amount of valuation reserve for inventory.

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Name:	us-gaap_InventoryValuationReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Inventory - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Inventory - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Inventory [Line Items]
Inventory valuation reserves	$ 282.5		$ 1.7
Cost of sales
Inventory [Line Items]
Inventory valuation gains (losses)	(280.8)	$ 52.1
LIFO inventory
Inventory [Line Items]
Inventory valuation reserves	$ 149.6		$ 1.2