Defined Benefit Plans (Components of Net Periodic Benefit Cost of Other Postretirement Benefit Pension Pans) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (9.9)	$ (9.8)	$ (29.5)	$ (31.9)
Net periodic benefit (cost)	(5.5)	(0.7)	(13.6)	(6.7)
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(0.1)	0.0	(0.3)	(0.3)
Interest cost	(1.3)	(1.2)	(3.8)	(3.5)
Amortization of prior service (cost) credit	0.6	0.6	1.6	1.8
Net periodic benefit (cost)	$ (0.8)	$ (0.6)	$ (2.5)	$ (2.0)