Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2018

Compensation And Retirement Disclosure [Abstract]

Schedule of components of period benefit costs

The components of periodic benefit costs for the three months ended March 31, 2018 and March 31, 2017 are as follows:

	Three Months Ended March 31, 2018
							Postretirement
	U.S.			Non-U.S.			Health and
	Pension			Pension			Other
($ in millions)	Plans			Plans			Plans
Service cost - benefits earned during the period	$	—		$	0.5		$	0.1
Interest cost of projected benefit obligations		1.3			0.5			0.2
Expected return on plan assets		(1.5	)		(0.4	)		—
Amortization of prior service cost		—			—			(0.7	)
Amortization of actuarial net loss		0.8			0.4			0.2
Net periodic benefit costs	$	0.6		$	1.0		$	(0.2	)

	Three Months Ended March 31, 2017
							Postretirement
	U.S.			Non-U.S.			Health and
	Pension			Pension			Other
($ in millions)	Plans			Plans			Plans
Service cost - benefits earned during the period	$	—		$	0.4		$	0.1
Interest cost of projected benefit obligations		1.3			0.6			0.2
Expected return on plan assets		(1.2	)		(0.4	)		—
Amortization of prior service costs		—			—			(0.3	)
Amortization of actuarial net loss		0.8			0.4			0.1
Net periodic benefit costs		0.9			1.0			0.1