PENSION AND OTHER POST-EMPLOYEMENT BENEFITS - Schedule of Assumed Rate of Return on Pension Plan Assets Considers Historical Market Returns and Economic Forecasts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pensions and OPEB
Defined Benefit Plan Disclosure [Line Items]
Actual gains or (losses) on plan assets - $ millions	$ 751	$ (1,830)	$ 689
Actual gains or (losses) on plan assets - %	11.20%	(19.10%)	7.90%
Expected return on plan assets - $ millions	$ 601	$ 696	$ 688
Expected return on plan assets		7.50%	7.50%
Pension
Defined Benefit Plan Disclosure [Line Items]
Actual gains or (losses) on plan assets - $ millions	682	$ (1,760)
Expected return on plan assets - $ millions	$ 570	$ 657	$ 652
Expected return on plan assets	8.00%	7.50%	7.50%
OPEB
Defined Benefit Plan Disclosure [Line Items]
Actual gains or (losses) on plan assets - $ millions	$ 69	$ (70)
Expected return on plan assets - $ millions	$ 31	$ 39	$ 36
Expected return on plan assets	7.00%	7.50%	7.50%