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. 28, 2018	Sep. 29, 2017	Sep. 28, 2018	Sep. 29, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (9.8)	$ (10.1)	$ (31.9)	$ (29.9)
Net periodic pension benefit (cost)	(0.7)	(1.8)	(6.7)	(7.7)
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	(0.1)	(0.3)	(0.5)
Interest cost	(1.2)	(1.1)	(3.5)	(3.7)
Amortization of prior service credit	(0.6)	(0.8)	(1.8)	(2.4)
Net periodic pension benefit (cost)	$ (0.6)	$ (0.4)	$ (2.0)	$ (1.8)