EMPLOYEE BENEFIT PLANS, Plan Allocations (Details)  | 
Mar. 31, 2020  | 
Mar. 31, 2019  | 
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| Employee Benefit Plans [Abstract] | ||
| Target allocation, percentage | 100.00% | 100.00% | 
| Actual allocation, percentage | 100.00% | 100.00% | 
| Equity Securities | ||
| Employee Benefit Plans [Abstract] | ||
| Target allocation, percentage | 25.30% | 25.40% | 
| Actual allocation, percentage | 23.00% | 24.10% | 
| Debt Securities | ||
| Employee Benefit Plans [Abstract] | ||
| Target allocation, percentage | 25.00% | 34.80% | 
| Actual allocation, percentage | 27.10% | 44.50% | 
| Property | ||
| Employee Benefit Plans [Abstract] | ||
| Target allocation, percentage | 7.40% | 7.40% | 
| Actual allocation, percentage | 6.50% | 6.10% | 
| Other Assets | ||
| Employee Benefit Plans [Abstract] | ||
| Target allocation, percentage | 42.30% | 32.40% | 
| Actual allocation, percentage | 43.40% | 25.30% | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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- Definition Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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