Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Inventory [Line Items]
Materials and supplies, net	$ 145.5	$ 130.8
Raw coal	83.5	98.3
Saleable coal	102.5	67.0
Inventories, net	$ 331.5	$ 296.1

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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