Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Benefits
Components of net periodic benefit cost
Service cost	$ 0.1	$ 0.0	$ 0.0
Interest cost	1.0	0.4	0.4
Recognition/establishment of Germany benefit obligation	0.0	0.0	0.0
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior service cost	0.0	0.0	0.0
Recognized net actuarial loss	0.4	0.0	0.0
Curtailment gain	0.0	0.0	0.0
Settlement loss	0.0	0.0	0.0
Net periodic pension benefit cost	1.5	0.4	0.4
U.S. Plans | Pension Benefits
Components of net periodic benefit cost
Service cost	3.7	3.9	3.9
Interest cost	22.1	20.6	22.9
Recognition/establishment of Germany benefit obligation	0.0	0.0	0.0
Expected return on plan assets	(24.7)	(24.6)	(25.9)
Amortization of prior service cost	0.0	0.0	0.0
Recognized net actuarial loss	5.1	6.6	5.9
Curtailment gain	0.0	0.0	0.0
Settlement loss	0.0	0.0	0.0
Net periodic pension benefit cost	6.2	6.5	6.8
Foreign Plan [Member] | Pension Benefits
Components of net periodic benefit cost
Service cost	9.8	11.0	10.5
Interest cost	6.5	6.2	5.7
Recognition/establishment of Germany benefit obligation	7.1	0.0	0.0
Expected return on plan assets	(12.3)	(10.5)	(4.5)
Amortization of prior service cost	(0.1)	0.0	0.0
Recognized net actuarial loss	(1.5)	(0.7)	(0.4)
Curtailment gain	0.0	0.0	0.1
Settlement loss	(0.9)	(2.2)	(0.6)
Net periodic pension benefit cost	$ 8.6	$ 3.8	$ 10.8