POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - PENSION PLANS WITH ACCUMULATED AND PROJECTED BENEFIT OBLIGATIONS IN EXCESS OF PLAN ASSETS (Details) - USD ($) $ in Millions	Jun. 30, 2017	Jun. 30, 2016
Accumulated Benefit Obligation Exceeds the Fair Value of Plan Assets
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	$ 13,699	$ 15,233
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation	12,276	13,587
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	8,279	8,082
Projected Benefit Obligation Exceeds the Fair Value of Plan Assets
Defined Benefit Plan, Pension Plans With Projected Benefit Obligations In Excess Of Plan Assets, Aggregate Projected Benefit Obligation	14,181	15,853
Defined Benefit Plan, Pension Plans With Projected Benefit Obligations In Excess Of Plan Assets, Aggregate Accumulated Benefit Obligation	12,630	14,149
Defined Benefit Plan, Pension Plans With Projected Benefit Obligations In Excess Of Plan Assets, Aggregate Fair Value Of Plan Assets	$ 8,654	$ 8,657