POST EMPLOYMENT BENEFITS - Plan assets distribution (Details)	Sep. 30, 2023	Sep. 30, 2022
Plan assets distribution
Plan assets distribution (in percent)	100.00%	100.00%
Cash
Plan assets distribution
Plan assets distribution (in percent)	3.31%	24.90%
Equity securities
Plan assets distribution
Plan assets distribution (in percent)	2.35%	6.20%
Debt securities
Plan assets distribution
Plan assets distribution (in percent)	91.23%	49.50%
Real estate mutual fund
Plan assets distribution
Plan assets distribution (in percent)	1.20%	5.90%
Other
Plan assets distribution
Plan assets distribution (in percent)	1.91%	13.50%