EMPLOYEE BENEFIT PLANS - Net Periodic Cost/(Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Defined Benefit Plan Disclosure
Service cost	$ 95	$ 0	$ 0
Interest cost	855	611	582
Expected return on plan assets	(1,060)	(1,319)	(1,522)
Amortization of prior service credit	0	0	0
Recognized net actuarial loss	240	255	354
Settlements	0	0	2
Net periodic cost/(benefit)	130	(453)	(584)
Other Postretirement and Postemployment Benefits
Defined Benefit Plan Disclosure
Service cost	71	70	86
Interest cost	200	128	117
Expected return on plan assets	(1)	(17)	(34)
Amortization of prior service credit	(5)	(5)	(6)
Recognized net actuarial loss	14	56	55
Settlements	0	0	0
Net periodic cost/(benefit)	$ 279	$ 232	$ 218