Retirement Plans (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 25, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.3	$ 0.4
Interest cost	1.7	3.5
Expected return on plan assets	(1.3)	(4.2)
Amortization of net actuarial loss	2.2	2.6
Amortization of prior service cost	0.1	0.0
Plan settlements	69.2	3.7
Net periodic benefit cost	73.2	6.0
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 0.0	$ 0.1