Inventories

3 Months Ended

Mar. 31, 2019

Inventory Disclosure [Abstract]

Inventories

9. Inventories

We value our raw materials, work in process, and finished goods inventories using lower of cost, as determined by the average cost method, or market. Supplies and materials are valued at the first-in, first-out (FIFO) or average cost methods.

The components of inventories were as follows (dollars in millions):

	March 31,		December 31,
	2019		2018
Raw materials	$	330.1	$	307.8
Work in process		13.6		13.9
Finished goods		210.5		199.0
Supplies and materials		277.5		274.9
Inventories	$	831.7	$	795.6