RETIREMENT PLANS - Allocation Plan Assets (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension | International
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	100.00%	100.00%
Pension | International | Cash
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	1.00%	1.00%
Pension | International | International equity
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	40.00%	41.00%
Pension | International | Corporate bonds
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	20.00%	21.00%
Pension | International | Government bonds
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	22.00%	22.00%
Pension | International | Total fixed income
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	42.00%	43.00%
Pension | International | Insurance company accounts
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	14.00%	14.00%
Pension | International | Real estate
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	1.00%	1.00%
Pension | International | Debt securities
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	2.00%
Pension and Postretirement Health Care Benefit Plans | United States
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	100.00%	100.00%
PERCENTAGE OF PLAN ASSETS	100.00%	100.00%
Pension and Postretirement Health Care Benefit Plans | United States | Cash
Asset allocation percentages
PERCENTAGE OF PLAN ASSETS	2.00%	1.00%
Pension and Postretirement Health Care Benefit Plans | United States | Large cap equity
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	27.00%	34.00%
PERCENTAGE OF PLAN ASSETS	26.00%	34.00%
Pension and Postretirement Health Care Benefit Plans | United States | Small cap equity
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	4.00%	9.00%
PERCENTAGE OF PLAN ASSETS	4.00%	8.00%
Pension and Postretirement Health Care Benefit Plans | United States | International equity
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	16.00%	15.00%
PERCENTAGE OF PLAN ASSETS	15.00%	15.00%
Pension and Postretirement Health Care Benefit Plans | United States | Core fixed income
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	30.00%	18.00%
PERCENTAGE OF PLAN ASSETS	29.00%	18.00%
Pension and Postretirement Health Care Benefit Plans | United States | High-yield bonds
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	4.00%	5.00%
PERCENTAGE OF PLAN ASSETS	3.00%	5.00%
Pension and Postretirement Health Care Benefit Plans | United States | Emerging markets
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	2.00%	2.00%
PERCENTAGE OF PLAN ASSETS	2.00%	2.00%
Pension and Postretirement Health Care Benefit Plans | United States | Real estate
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	6.00%	6.00%
PERCENTAGE OF PLAN ASSETS	7.00%	7.00%
Pension and Postretirement Health Care Benefit Plans | United States | Private Equity
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	8.00%	8.00%
PERCENTAGE OF PLAN ASSETS	9.00%	7.00%
Pension and Postretirement Health Care Benefit Plans | United States | Distressed debt
Asset allocation percentages
TARGET ASSET ALLOCATION PERCENTAGE	3.00%	3.00%
PERCENTAGE OF PLAN ASSETS	3.00%	3.00%