POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - ESOP SHARES OUTSTANDING (Details) - shares shares in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Series A Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	29,591	31,600	34,233
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	2,479	3,259	4,117
Employee Stock Ownership Plan (ESOP), Shares in ESOP	32,070	34,859	38,350
Series B Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	27,894	26,790	25,895
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	24,418	26,471	28,512
Employee Stock Ownership Plan (ESOP), Shares in ESOP	52,312	53,261	54,407