POSTRETIREMENT BENEFITS (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 5.7	$ 8.4
Interest cost	105.4	61.4	$ 51.3
Amortization of prior service cost	(0.4)	(0.7)	(0.6)
Net periodic benefit cost	20.7	33.0	27.5
Included in Pretax Other Comprehensive Income (Loss)
Liability adjustment	16.4	(59.9)	(245.9)
Amortization of prior service costs and actuarial losses	0.2	35.5	54.3
Other Postretirement Benefit Plans, Defined Benefit
Components of Net Periodic Benefit Cost [Abstract]
Service cost	0.7	1.1	1.3
Interest cost	1.8	1.1	1.0
Amortization of prior service cost	0.1	0.1	0.1
Recognized actuarial loss	0.5	1.5	2.1
Net periodic benefit cost	(3.1)	(3.8)	(4.5)
Included in Pretax Other Comprehensive Income (Loss)
Liability adjustment	1.7	(12.2)	(3.8)
Amortization of prior service costs and actuarial losses	$ (0.6)	$ (1.6)	$ (2.2)