Pension and Postretirement Plans (Tables)

6 Months Ended

Jun. 30, 2018

Retirement Benefits, Description [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

For the three and six months ended June 30, 2018 and 2017, pension and postretirement benefit costs (benefits) were as follows:

	Three Months Ended June 30, 2018
	2018			2017			2018			2017
(dollars in millions)	Pension Benefits						Postretirement and Other Benefits
Service cost	$	—		$	—		$	—		$	—
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation	4.1			4.9			0.8			0.8
Expected return on plan assets	(6.2		)	(6.5		)	—			—
Amortization of:
Prior service benefit	—			—			(0.8		)	(1.1		)
Actuarial loss	4.2			4.4			1.1			1.2
Total amortization	4.2			4.4			0.3			0.1
Pension / postretirement costs	$	2.1		$	2.8		$	1.1		$	0.9

	Six Months Ended June 30, 2018
	2018			2017			2018			2017
(dollars in millions)	Pension Benefits						Postretirement and Other Benefits
Service cost	$	—		$	—		$	0.1		$	0.1
Other components of pension and postretirement benefit plans expense:
Interest cost on projected benefit obligation	8.3			9.7			1.6			1.6
Expected return on plan assets	(12.4		)	(13.0		)	—			—
Amortization of:
Prior service benefit	—			—			(1.6		)	(2.2		)
Actuarial loss	8.5			8.8			2.1			2.3
Total amortization	8.5			8.8			0.5			0.1
Pension / postretirement costs	$	4.4		$	5.5		$	2.2		$	1.8