Defined Benefit Plans (Components of Net Periodic Benefit Cost of Other Postretirement Benefit Pension Pans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (10.9)	$ (7.5)	$ (17.0)	$ (15.0)
Net periodic benefit (cost)	(5.8)	(2.5)	(6.6)	(4.9)
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(0.1)	(0.1)	(0.2)	(0.2)
Interest cost	(0.9)	(1.3)	(1.7)	(2.5)
Amortization of prior service (cost) credit	0.6	0.5	1.1	1.0
Net periodic benefit (cost)	$ (0.4)	$ (0.9)	$ (0.8)	$ (1.7)