Pension and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2012

Pension and Other Postretirement Benefits

Schedule of net periodic benefit cost

	Three months ended September 30,						Nine months ended September 30,
	2012			2011			2012			2011
	(in millions)
Pension Plans
Service cost for benefits earned during the period	$	3.1		$	2.8		$	9.3		$	8.5
Interest cost on projected benefit obligation		8.6			9.0			25.8			26.9
Expected return on plan assets		(8.6	)		(8.8	)		(25.9	)		(26.4	)
Amortization of actuarial loss		2.5			1.5			7.4			4.5
Net periodic benefit cost	$	5.6		$	4.5		$	16.6		$	13.5
Retiree Medical
Service cost for benefits earned during the period	$	0.7		$	0.7		$	2.2		$	2.0
Interest cost on projected benefit obligation		0.9			1.1			2.7			3.2
Curtailment gain		(10.9	)		—			(10.9	)		—
Amortization of transition obligation		0.1			0.1			0.3			0.3
Amortization of actuarial loss		0.1			0.2			0.5			0.7
Net periodic benefit cost (income)	$	(9.1	)	$	2.1		$	(5.2	)	$	6.2