Inventories, Net - Schedule of Inventories Net (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Finished products	$ 667.0	$ 643.6
Products in process	37.1	41.9
Raw materials	35.3	32.4
Supplies and expendable parts	149.9	141.5
Total inventories	889.3	859.4
Less: allowances	(180.3)	(168.6)
Inventories, net	$ 709.0	$ 690.8

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Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount of valuation reserve for inventory.

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Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

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