Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Components of net periodic benefit cost (credit):
Recognition of net actuarial (gains) losses	$ (1.0)	$ 11.6	$ (1.9)	$ 14.2
Pension Plan
Components of net periodic benefit cost (credit):
Service cost	0.7	2.2	1.2	4.5
Interest cost	7.4	5.5	14.3	11.1
Expected return on plan assets	(4.9)	(7.4)	(9.5)	(15.1)
Amortization of prior service cost	0.1	0.4	0.2	0.7
Recognition of net actuarial (gains) losses	(1.0)	11.6	(1.9)	14.2
Net periodic benefit cost (credit)	2.3	12.3	4.3	15.4
Pension Plan | U.S. Plans
Components of net periodic benefit cost (credit):
Service cost	0.2	1.8	0.4	3.7
Interest cost	4.5	4.1	9.0	8.2
Expected return on plan assets	(2.1)	(5.0)	(4.2)	(10.2)
Amortization of prior service cost	0.1	0.3	0.1	0.6
Recognition of net actuarial (gains) losses	(1.0)	11.6	(1.9)	14.2
Net periodic benefit cost (credit)	1.7	12.8	3.4	16.5
Pension Plan | International Plans
Components of net periodic benefit cost (credit):
Service cost	0.5	0.4	0.8	0.8
Interest cost	2.9	1.4	5.3	2.9
Expected return on plan assets	(2.8)	(2.4)	(5.3)	(4.9)
Amortization of prior service cost	0.0	0.1	0.1	0.1
Recognition of net actuarial (gains) losses	0.0	0.0	0.0	0.0
Net periodic benefit cost (credit)	$ 0.6	$ (0.5)	$ 0.9	$ (1.1)