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, 2019	Jun. 30, 2018
Accumulated Benefit Obligation Exceeds the Fair Value of Plan Assets
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	$ 11,604	$ 8,467
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	10,711	7,573
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets	6,026	3,740
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	16,304	8,962
Defined Benefit Plan, Pension Plans With Projected Benefit Obligations In Excess Of Plan Assets, Aggregate Accumulated Benefit Obligation	15,096	7,974
Defined Benefit Plan, Pension Plans With Projected Benefit Obligations In Excess Of Plan Assets, Aggregate Fair Value Of Plan Assets	$ 10,630	$ 4,150