PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Period Increase (Decrease)	$ 25
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)	$ 11
Defined Benefit Plan Funded Status Period Increase Decrease						$ 14
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Period Increase (Decrease), Percentage	1.00%			1.00%
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease), Percentage	1.00%			1.00%
U.S.
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan	$ (1,500)
Pension
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Payment for Settlement		$ 449	$ 455
Reduction in settlement charge	$ 0	$ 6		$ 0	$ (449)