Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Components of net periodic benefit cost
Contributions to qualified and non qualified pension plans	$ 13.7	$ 11.9
Defined Benefits Plan, Expected Future Reimbursement from CTA, Net Fiscal Year	13.0
Pension Plan [Member]
Components of net periodic benefit cost
Other		0.0
Benefit Plan, Plan Assets, Reimbursement from CTA			$ 12.2
Other Postretirement Benefits Plan [Member]
Components of net periodic benefit cost
Service cost	0.0	0.0
Interest cost	(0.1)	(0.1)
Expected return on plan assets	0.0	0.0
Recognized net actuarial loss	0.0	0.0
Other	0.0	0.0
Net periodic pension benefit cost	0.1	0.1
Domestic Plan [Member] | Pension Plan [Member]
Components of net periodic benefit cost
Service cost	1.0	0.9
Interest cost	(4.7)	(5.5)
Expected return on plan assets	(6.3)	(6.2)
Recognized net actuarial loss	1.9	1.3
Net periodic pension benefit cost	1.3	1.5
Foreign Plan [Member] | Pension Plan [Member]
Components of net periodic benefit cost
Service cost	2.5	2.5
Interest cost	(1.0)	(1.6)
Expected return on plan assets	(3.3)	(3.1)
Recognized net actuarial loss	(0.1)	(0.4)
Other	(0.1)
Net periodic pension benefit cost	$ 0.2	$ 0.6