Pension and Postretirement Benefit Costs (Tables)

9 Months Ended

Sep. 30, 2015

Pension Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic pension cost included the following components:

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2015			2014			2015			2014
	(Dollars in millions)
Service cost for benefits earned	$	0.7		$	0.6		$	2.0		$	1.6
Interest cost on projected benefit obligation	10.1			11.3			30.3			34.0
Expected return on plan assets	(12.0		)	(13.6		)	(36.1		)	(40.7		)
Amortization of prior service cost and net actuarial loss	10.0			7.9			30.4			23.6
Net periodic pension cost	$	8.8		$	6.2		$	26.6		$	18.5

Other Postretirement Benefit Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic postretirement benefit cost included the following components:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2015		2014		2015		2014
	(Dollars in millions)
Service cost for benefits earned	$	2.8	$	3.1	$	8.4	$	9.2
Interest cost on accumulated postretirement benefit obligation	8.4		9.1		25.3		27.3
Amortization of prior service cost and net actuarial loss	4.6		3.9		13.6		11.8
Net periodic postretirement benefit cost	$	15.8	$	16.1	$	47.3	$	48.3