POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - ESOP SHARES OUTSTANDING (Details) - shares shares in Thousands	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Series A Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	36,488	39,241	42,044
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	5,060	6,095	7,228
Employee Stock Ownership Plan (ESOP), Shares in ESOP	41,548	45,336	49,272
Series B Preferred Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares	25,378	23,925	23,074
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares	30,412	32,319	34,096
Employee Stock Ownership Plan (ESOP), Shares in ESOP	55,790	56,244	57,170