EMPLOYEE BENEFIT PLANS - NET PENSION EXPENSE (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Restructuring Charges	$ 322.0	$ 0.0	$ 322.0	$ 0.0
Restructuring Charges	322.0	0.0	322.0	0.0
Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	11.0	11.0	37.0	32.0
Interest cost	19.0	23.0	57.0	67.0
Expected return on assets	(28.0)	(24.0)	(83.0)	(71.0)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1.0)	(1.0)	(1.0)	(1.0)
Recognized actuarial loss (gain)	9.0	9.0	26.0	27.0
Restructuring Charges			16.0
Restructuring Charges			16.0
Wages and Benefits [Member] | Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net pension expense	11.0	11.0	37.0	32.0
Nonoperating Income (Expense) [Member] | Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net pension expense	$ (1.0)	$ 7.0	$ (1.0)	$ 22.0