Inventories (Tables)

3 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories are valued at the lower of cost (on a first-in, first-out basis) and net realizable value. Inventory balances were as follows:

($ in millions)	March 31, 2018		December 31, 2017
Raw materials	$	92.0	$	88.6
Work in process	40.1		31.8
Finished goods	83.6		94.8
	$	215.7	$	215.2