Inventories

9 Months Ended

Sep. 30, 2018

Inventory, Net [Abstract]

Inventories

Inventories

Inventories consist of the following:	September 30, 2018		December 31, 2017
Raw materials	$	142.1	$	106.2
Work-in-process	58.7		49.6
Finished goods	41.9		40.9
Operating and other supplies	147.7		120.8
Total inventories	$	390.4	$	317.5

Inventories are stated at the lower of cost or Net Realizable Value ("NRV") using the first-in, first-out ("FIFO") or the weighted average cost method.