Retirement Benefits - Components of Net Periodic Benefit Cost for Defined Benefit Plans and Other Postretirement Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.2	$ 0.2
Interest cost	0.1	0.1
Net amortization	(0.1)	(0.2)
Net periodic (benefit) cost	0.2	0.1
U.S. | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0
Interest cost	0.1	0.1
Expected return on plan assets	(0.1)	(0.2)
Net amortization	0.1	0.1
Net periodic (benefit) cost	0.1	0.0
Non-U.S. | Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.5	0.5
Interest cost	0.2	0.2
Expected return on plan assets	(0.3)	(0.2)
Net amortization	0.2	0.5
Net periodic (benefit) cost	$ 0.6	$ 1.0