Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Components of net periodic benefit cost
Contributions to qualified and non qualified pension plans	$ 22.6	$ 6.9
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
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	1.0
Interest cost	5.2	5.7
Expected return on plan assets	(6.2)	(6.5)
Recognized net actuarial loss	1.6	1.5
Net periodic pension benefit cost	1.6	1.7
Foreign Plan [Member] | Pension Plan [Member]
Components of net periodic benefit cost
Service cost	2.8	2.6
Interest cost	1.6	2.2
Expected return on plan assets	(2.7)	(2.1)
Recognized net actuarial loss	(0.2)	(0.1)
Net periodic pension benefit cost	$ 1.5	$ 2.6