RETIREMENT BENEFITS PLANS - Other Postretirement Benefits Plan Assumptions (Details) - Other postretirement benefits plans	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assumptions used to determine benefit obligation at year-end (as a percent)
Discount rate	2.79%	2.37%	3.13%
Health care cost trend rate assumed for next year	7.45%	7.05%	6.95%
Ultimate health care cost trend rate	4.75%	4.75%	4.75%
Year ultimate health care cost trend rate is achieved	2031	2030	2029
Assumptions used to determine expense (as a percent)
Discount rate used to determine benefit obligation	2.44%	3.13%	4.23%
Discount rate used to determine service cost	2.76%	3.25%	4.29%
Discount rate used to determine interest cost	1.70%	2.67%	3.85%
Initial health care cost trend rate	7.38%	6.95%	7.10%
Ultimate health care cost trend rate	4.75%	4.75%	4.75%
Year ultimate health care cost trend rate is achieved	2030	2029	2028