PENSION AND OTHER POSTRETIREMENT PLANS (Schedule of Assumptions Used in Calculating the Net Benefit Obligation) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Defined Benefit Plan Disclosure
Net benefit obligation, Weighted average discount rate	2.08%	2.98%	4.08%
Lump sum assumed interest rates for First 5 years	0.53%	2.01%	3.33%
Lump sum assumed interest rates for Next 15 years	2.31%	3.06%	4.39%
Lump sum assumed interest rates for All future years	3.09%	3.65%	4.72%
Net pension expense, Weighted average discount rate	2.98%	4.08%	3.46%
Expected long-term rate of return	6.50%	6.50%	6.50%
SERP Benefits
Defined Benefit Plan Disclosure
Net benefit obligation, Weighted average discount rate	2.08%	2.98%	4.08%
Net pension expense, Weighted average discount rate	2.98%	4.08%	3.46%
Expected long-term rate of return	6.50%	6.50%	6.50%