PENSION AND OTHER POSTRETIREMENT BENEFIT PROGRAMS - Net Periodic Benefit Cost Relating to Pension and Other Postemployment Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension benefits
Net periodic benefit cost
Service cost	$ 19	$ 22
Interest cost	24	18
Expected return on plan assets	(39)	(36)
Amortization of net losses and prior service costs	12	23
Net periodic cost (income)	16	27
OPEB
Net periodic benefit cost
Interest cost	1	1
Amortization of net losses and prior service costs	(3)	(2)
Net periodic cost (income)	$ (2)	$ (1)