PENSION BENEFITS - Weighted Average Discount (Details) - Pension Plan	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Weighted-average discount rate	1.96%	2.75%
Weighted-average rate of increase in compensation levels (1)	3.32%	3.96%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Weighted-average discount rate	2.75%	2.46%	2.58%
Weighted-average rate of increase in compensation levels (1)	3.96%	3.98%	3.97%
Weighted-average expected long-term rate of return on plan assets	5.40%	5.50%	5.50%