Pension and Postretirement Benefit Costs (Tables)

6 Months Ended

Jun. 30, 2011

Pension and Postretirement Benefit Costs [Abstract]

Net periodic pension costs

	Three Months Ended June 30,						Six Months Ended June 30,
	2011			2010			2011			2010
				(Dollars in millions)
Service cost for benefits earned	$	0.5		$	0.4		$	0.9		$	0.8
Interest cost on projected benefit obligation		12.5			12.6			24.9			25.2
Expected return on plan assets		(16.1	)		(15.0	)		(32.2	)		(29.2	)
Amortization of prior service cost		0.2			0.4			0.5			0.7
Amortization of actuarial loss		7.5			5.5			15.0			11.0
Net periodic pension costs	$	4.6		$	3.9		$	9.1		$	8.5

Net periodic postretirement benefit costs

	Three Months Ended June 30,				Six Months Ended June 30,
	2011		2010		2011		2010
			(Dollars in millions)
Service cost for benefits earned	$	3.2	$	3.1	$	6.5	$	6.2
Interest cost on accumulated postretirement benefit obligation		14.5		14.6		28.9		29.1
Amortization of prior service cost		0.5		0.5		1.0		1.0
Amortization of actuarial loss		6.8		6.3		13.5		12.7
Net periodic postretirement benefit costs	$	25.0	$	24.5	$	49.9	$	49.0