EMPLOYEE BENEFIT PLANS - Actuarial Assumptions to Determined Funded Status (Details)	Dec. 31, 2020	Dec. 31, 2019
United States
Summary of weighted-average actuarial assumptions used in determining funded status
Discount rate (as a percent)	2.60%	3.30%
Rate of increase in compensation levels (as a percent)	3.00%	3.00%
Foreign
Summary of weighted-average actuarial assumptions used in determining funded status
Discount rate (as a percent)	1.53%	2.30%
Rate of increase in compensation levels (as a percent)	3.11%	3.11%