Pension and Postretirement Plans (Tables)

3 Months Ended

Mar. 31, 2019

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

For the three months ended March 31, 2019 and 2018, pension and postretirement benefit costs (benefits) were as follows:

	Three Months Ended March 31,
	2019			2018			2019			2018
(dollars in millions)	Pension Benefits						Postretirement and Other Benefits
Service cost	$	—		$	—		$	0.2		$	0.1
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation	6.0			4.2			1.2			0.8
Expected return on plan assets	(7.8		)	(6.2		)	—			—
Amortization of:
Prior service benefit	—			—			(0.6		)	(0.8		)
Actuarial loss	3.4			4.3			0.4			1.0
Total amortization	3.4			4.3			(0.2		)	0.2
Pension / postretirement costs	$	1.6		$	2.3		$	1.2		$	1.1