POSTRETIREMENT BENEFIT PLANS - Components of Net Periodic Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Non-operating	$ (123)	$ (1)	$ (238)	$ (3)
Defined benefit plans
Defined Benefit Plan Disclosure [Line Items]
Service cost – Operating	15	5	29	10
Interest cost	290	5	582	9
Expected return on plan assets	(357)	(7)	(713)	(14)
Amortization of net loss (gain)	(32)	1	(61)	3
Amortization of prior service cost (credit)	(1)	(1)	(2)	(2)
Non-operating	(100)	(2)	(194)	(4)
Net periodic expense (income)	(85)	3	(165)	6
Other postretirement plans
Defined Benefit Plan Disclosure [Line Items]
Service cost – Operating	2	0	4	0
Interest cost	15	0	30	0
Expected return on plan assets	0	0	0	0
Amortization of net loss (gain)	(16)	0	(32)	0
Amortization of prior service cost (credit)	(22)	0	(44)	0
Non-operating	(23)	0	(46)	0
Net periodic expense (income)	$ (21)	$ 0	$ (42)	$ 0