EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 14.3	$ 15.1	$ 28.7	$ 28.9
Interest cost	1.4	1.7	2.7	3.5
Expected return on plan assets	(3.5)	(3.1)	(7.1)	(6.2)
Amortization of prior service cost and actuarial loss	0.0	0.0	0.0	0.1
Net periodic benefit cost	12.2	13.7	24.3	26.3
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.2	0.5	0.5
Interest cost	0.0	0.1	0.1	0.2
Amortization of prior service cost and actuarial loss	0.2	0.2	0.4	0.3
Net periodic benefit cost	$ 0.3	$ 0.5	$ 1.0	$ 1.0