RETIREMENT BENEFIT PLANS - Changes in Defined Benefit Plan Obligations (Details) - Retirement Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning balance	$ 303.0	$ 512.8
Service cost	0.2	0.0	$ 0.6
Interest cost	14.0	8.8	8.9
Actuarial (gains)/losses	5.0	(154.3)
Exchange difference	17.2	(50.7)
Benefits paid	(13.6)	(13.6)
Benefit obligation, ending balance	$ 325.8	$ 303.0	$ 512.8