Retirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2021
Components of net periodic benefit cost:
Recognition of net actuarial losses	$ 3.5	$ 8.8	$ 4.4	$ 8.8
Pension Plan
Components of net periodic benefit cost:
Service cost	2.8	3.1	5.8	6.2
Interest cost	5.6	6.6	11.1	13.3
Expected return on plan assets	(8.7)	(8.5)	(17.3)	(17.0)
Amortization of prior service cost	0.4	0.5	0.7	0.9
Recognition of net actuarial losses	3.5	8.8	4.4	8.8
Net periodic benefit cost (credit)	3.6	10.5	4.7	12.2
Pension Plan | Subsequent Event
Components of net periodic benefit cost:
Defined Benefit Plan, Expected Future Benefit Payment, Remainder of Fiscal Year					$ 15.0
Defined Benefit Plan, Expected Future Benefit Payment, Remainder of Fiscal Year					$ 15.0
Pension Plan | United States
Components of net periodic benefit cost:
Service cost	2.3	2.7	4.8	5.4
Interest cost	4.5	5.3	8.9	10.5
Expected return on plan assets	(6.1)	(6.4)	(12.2)	(12.7)
Amortization of prior service cost	0.3	0.4	0.6	0.8
Recognition of net actuarial losses	3.5	8.8	4.4	8.8
Net periodic benefit cost (credit)	4.5	10.8	6.5	12.8
Deferred Compensation Arrangement with Individual, Compensation Expense			9.6
Deferred Compensation Arrangement with Individual, Compensation Expense			9.6
Pension Plan | Foreign Plan
Components of net periodic benefit cost:
Service cost	0.5	0.4	1.0	0.8
Interest cost	1.1	1.3	2.2	2.8
Expected return on plan assets	(2.6)	(2.1)	(5.1)	(4.3)
Amortization of prior service cost	0.1	0.1	0.1	0.1
Recognition of net actuarial losses	0.0		0.0	0.0
Net periodic benefit cost (credit)	$ (0.9)	$ (0.3)	$ (1.8)	$ (0.6)