BENEFIT PLANS - Components of Net Periodic Benefit Cost- Other Postretirement Benefits (Details) - Other Postretirement Benefit Plans, Defined Benefit - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 0.6	$ 0.5
Interest cost	0.5	0.5
Amortization of prior service cost	0.4	0.4
Amortization of actuarial gain	(0.2)	(0.4)
Net periodic pension benefit cost	1.3	1.0
Pretax reclassifications from AOCI included in net periodic postretirement benefit credit	$ 0.2	$ 0.0