PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 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%
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease), Percentage		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		$ 0	$ 6		$ 0	$ (449)