BENEFIT PLANS (Combined Funded Status of Plans and their Reconciliation with Related Amounts Recognized in Consolidated Financial Statements - Postretirement Benefits) (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in Benefit Obligation
Projected benefit obligation at beginning of year	$ 41.8	$ 46.0
Service cost	2.0	2.3	$ 1.2
Interest cost	2.0	0.9	0.5
Actuarial (gain) loss	3.6	(2.5)
Benefits paid	(5.2)	(4.9)
Projected benefit obligation at end of year	44.2	41.8	46.0
Change in Fair Value of Plan Assets
Fair value of assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Fair value of assets at end of year	0.0	0.0	$ 0.0
Funded status	(44.2)	(41.8)
Amounts Recognized in the Consolidated Balance Sheets
Current liabilities	(5.2)	(5.1)
Noncurrent liabilities	(39.0)	(36.7)
Net amount recognized	(44.2)	(41.8)
Amounts Recognized in Accumulated Other Comprehensive Income
Net actuarial gain	(12.7)	(17.9)
Prior service credit	11.7	13.1
Total amount recognized	$ (1.0)	$ (4.8)