BENEFIT PLANS - Weighted-average Assumptions Used to Determine Benefit Obligations (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Discount rate	2.80%	3.50%
Expected return on plan assets	7.00%	7.00%
Rate of compensation increase	3.50%	3.50%
Post-retirement Benefits [Member]
Weighed average assumption used in calculating benefit obligations [Abstract]
Discount rate	2.80%	3.60%