Employee Benefit Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - Pension Plans - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5.9	$ 6.2	$ 11.9	$ 12.3
Interest cost	10.0	11.7	19.9	23.5
Expected return on plan assets	(14.2)	(13.0)	(28.4)	(26.0)
Net amortization of unrecognized amounts, Prior service cost	1.1	1.6	2.2	3.1
Net amortization of unrecognized amounts, Actuarial loss (income)	2.7	1.7	5.3	3.5
Net periodic benefit cost	$ 5.5	$ 8.2	$ 10.9	$ 16.4