Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2013

Retirement Plans

Components of net periodic benefit cost

	Pension Benefits												Post-retirement Benefits
	Three Months Ended						Six Months Ended						Three Months Ended				Six Months Ended
	June 30,						June 30,						June 30,				June 30,
(in millions)	2013			2012			2013			2012			2013		2012		2013		2012
Service cost	$	1.3		$	1.2		$	2.6		$	2.3		$	—	$	—	$	—	$	—
Interest cost	2.0			2.5			3.9			5.0			0.1		0.1		0.1		0.2
Expected return on plan assets	(3.1		)	(3.5		)	(6.1		)	(7.1		)	—		—		—		—
Amortization of unrecognized loss	1.4			1.3			2.8			2.6			—		—		0.1		—
Net periodic benefit cost	$	1.6		$	1.5		$	3.2		$	2.8		$	0.1	$	0.1	$	0.2	$	0.2