Inventories (Tables)

3 Months Ended

Mar. 31, 2018

Inventory Disclosure [Abstract]

Schedule of the components of inventories

The components of inventories as of March 31, 2018 and December 31, 2017 are summarized as follows:

($ in millions)	March 31, 2018			December 31, 2017
Raw materials	$	144.6		$	122.0
Work-in-process		136.6			98.8
Finished goods		241.4			227.7
Total inventories		522.6			448.5
Excess and obsolete inventory reserve		(51.1	)		(47.9	)
Inventories — net	$	471.5		$	400.6