EMPLOYEE BENEFIT PLANS (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 59.0	$ 43.6	$ 47.4
Interest cost	6.9	8.3	5.8
Expected return on plan assets	(12.5)	(9.6)	(8.5)
Amortization of prior service cost and actuarial loss	0.3	0.3	0.2
Net periodic benefit cost	53.7	42.6	44.9
Post Retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.0	1.0	1.1
Interest cost	0.4	0.7	0.7
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior service cost and actuarial loss	0.6	0.5	0.7
Net periodic benefit cost	$ 2.0	$ 2.2	$ 2.5