Benefit Plans - Changes in Projected Benefit Obligation, Fair Value of Plan Assets and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets:
Balance	$ 258.1
Balance	249.2	$ 258.1
Pension benefits
Change in benefit obligation:
Balance	(298.9)	(287.9)
Service cost	(1.6)	(1.5)	$ (1.4)
Interest cost	(6.2)	(7.1)	(9.2)
Participants’ contributions	(0.6)	(0.3)
Actuarial (loss) gain	12.1	(22.1)
Amendments/transfers in	2.0	0.0
Benefits paid	7.1	6.2
Curtailment gain	0.0	0.1
Settlement loss	13.1	18.6
Foreign currency translation	3.2	(4.9)
Balance	(269.8)	(298.9)	(287.9)
Change in plan assets:
Balance	258.1	244.1
Actual return on plan assets	6.1	31.8
Employer contribution	3.6	4.8
Participants’ contributions	0.6	0.3
Benefits paid	(5.2)	(6.0)
Settlement loss	(13.1)	(18.6)
Foreign currency translation	(0.9)	1.7
Balance	249.2	258.1	244.1
Funded status at end of year	(20.6)	(40.8)
Other retirement benefits
Change in benefit obligation:
Balance	(6.1)	(6.6)
Service cost	0.0	0.0	0.0
Interest cost	(0.2)	(0.2)	(0.2)
Participants’ contributions	(0.5)	(0.1)
Actuarial (loss) gain	0.9	0.5
Amendments/transfers in	0.0	0.0
Benefits paid	0.3	0.3
Curtailment gain	0.0	0.0
Settlement loss	0.0	0.0
Foreign currency translation	0.0	0.0
Balance	(5.6)	(6.1)	(6.6)
Change in plan assets:
Balance	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contribution	(0.2)	0.2
Participants’ contributions	0.5	0.1
Benefits paid	(0.3)	(0.3)
Settlement loss	0.0	0.0
Foreign currency translation	0.0	0.0
Balance	0.0	0.0	$ 0.0
Funded status at end of year	$ (5.6)	$ (6.1)