EMPLOYEE BENEFIT PLANS (Changes in Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plans
Change in benefit obligation:
Benefit obligation at beginning of year	$ 429.7	$ 357.0
Service cost	53.4	48.1	$ 55.6
Interest cost	20.3	17.7	7.9
Plan amendments	0.0	0.0
Benefit payments	(15.5)	(18.1)
Actuarial loss (gain)	1.9	25.0
Projected benefit obligation at end of year	489.8	429.7	357.0
Change in plan assets:
Fair value of plan assets at beginning of year	349.3	274.2
Actual return on plan assets	25.9	34.8
Benefits paid	(15.5)	(18.1)
Employer contributions	35.0	58.4
Fair value of plan assets at end of year	394.7	349.3	274.2
Reconciliation of funded status:
Fair value of plan assets at end of year	394.7	349.3	274.2
Less projected benefit obligation at end of year	489.8	429.7	357.0
Funded status at end of year	(95.1)	(80.4)
Post-Retirement Medical Plan
Change in benefit obligation:
Benefit obligation at beginning of year	19.6	13.9
Service cost	0.9	0.5	0.8
Interest cost	0.9	0.7	0.3
Plan amendments	0.0	6.0
Benefit payments	(2.4)	(1.4)
Actuarial loss (gain)	(3.4)	(0.1)
Projected benefit obligation at end of year	15.6	19.6	13.9
Change in plan assets:
Fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Benefits paid	(2.4)	(1.4)
Employer contributions	2.4	1.4
Fair value of plan assets at end of year	0.0	0.0	0.0
Reconciliation of funded status:
Fair value of plan assets at end of year	0.0	0.0	0.0
Less projected benefit obligation at end of year	15.6	19.6	$ 13.9
Funded status at end of year	$ (15.6)	$ (19.6)