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
	Oct. 02, 2020	Sep. 27, 2019	Oct. 02, 2020	Sep. 27, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (11.0)	$ (7.7)	$ (28.0)	$ (22.7)
Net periodic cost	(7.6)	(3.5)	(14.2)	(8.4)
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	(0.1)	(0.1)	(0.3)	(0.3)
Interest cost	(0.9)	(1.3)	(2.6)	(3.8)
Amortization of actuarial loss	(0.3)	0.0	(0.3)	0.0
Amortization of prior service credit	0.6	0.6	1.7	1.6
Net periodic cost	$ (0.7)	$ (0.8)	$ (1.5)	$ (2.5)