Pension Plans (Tables)

6 Months Ended

Jun. 30, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Periodic Pension Costs

The following sets forth the components of our net periodic pension costs associated with these plans ($ in millions):

	Three Months Ended						Six Months Ended
	June 30, 2017			July 1, 2016			June 30, 2017			July 1, 2016
Service cost	$	1.0		$	0.9		$	2.0		$	1.7
Interest cost	1.5			1.9			2.9			3.8
Expected return on plan assets	(1.8		)	(2.1		)	(3.6		)	(4.1		)
Amortization of net loss	1.1			1.5			2.2			2.8
Net periodic pension cost	$	1.8		$	2.2		$	3.5		$	4.2