PENSION AND OTHER POST-EMPLOYMENT BENEFIT PLANS - Net Periodic Benefit Cost and Assumptions used to Estimate our Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	1 Months Ended	11 Months Ended	12 Months Ended
	Jan. 31, 2019	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.40%	4.30%
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 42	$ 36	$ 32
Interest cost			98	139	160
Expected return on plan assets			(204)	(234)	(223)
Amortization of actuarial loss			115	122	112
Amortization of prior service cost (credit)			3	3	4
Settlement charges			0	253	455
Net periodic benefit cost			$ 54	$ 319	$ 540
Discount rate			2.50%
Expected return on assets			6.00%	6.50%	7.00%
Lump sum or installment distributions election			60.00%	60.00%	60.00%
Pension | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate				3.10%	3.70%
Rate of compensation increase			2.00%	2.00%	2.00%
Pension | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate				3.40%	4.40%
Rate of compensation increase			13.00%	13.00%	13.00%
Other Post-employment Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 0	$ 0	$ 0
Interest cost			3	4	6
Expected return on plan assets			0	0	0
Amortization of actuarial loss			5	4	7
Amortization of prior service cost (credit)			(1)	(1)	(5)
Settlement charges			0	0	0
Net periodic benefit cost			$ 7	$ 7	$ 8
Discount rate				3.00%
Other Post-employment Benefits | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate			2.10%		3.70%
Weighted health care cost trend rate assumed		4.50%	4.50%	4.50%	4.50%
Other Post-employment Benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate			2.40%		4.20%
Rate of compensation increase			13.00%
Weighted health care cost trend rate assumed		7.80%	6.80%	7.30%	7.80%