Defined Benefit Plans (Components of Net Periodic Benefit Cost of Other Postretirement Benefit Pension Pans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2019	Mar. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (9.8)	$ (10.9)
Net periodic benefit cost	(4.6)	(3.1)
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(0.1)	(0.1)
Interest cost	(1.2)	(1.2)
Amortization of prior service (cost) credit	0.5	0.6
Net periodic benefit cost	$ (0.8)	$ (0.7)