PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS - Net Amounts Recognized (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Net amounts recognized in the balance sheets at December 31
Benefit obligations	$ 192.3	$ 197.0
Cash contributions and benefit payments to unfunded plans	2.5
Additional cash contributions, including benefit payments to unfunded plans	$ 6.7