POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - ESOP SHARES OUTSTANDING (Details) - shares shares in Thousands	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Series A Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	31,600	34,233	36,488
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	3,259	4,117	5,060
Employee Stock Ownership Plan (ESOP), Shares in ESOP	34,859	38,350	41,548
Series B Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	26,790	25,895	25,378
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	26,471	28,512	30,412
Employee Stock Ownership Plan (ESOP), Shares in ESOP	53,261	54,407	55,790