POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - FAIR VALUE OF PLAN ASSETS (Details) - USD ($) $ in Millions		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Pension Plan
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[1]	$ 11,382	$ 11,267	$ 10,829
Pension Plan | Fair Value, Inputs, Level 1, 2 and 3 [Member]
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		425	536
Pension Plan | Cash and Cash Equivalents | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		47	136
Pension Plan | Company Stock | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		0	0
Pension Plan | Other Assets | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[2]	378	400
Pension Plan | Other Assets | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[2]	0	165
Pension Plan | Other Assets | Fair Value Measured at Net Asset Value Per Share [Member]
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		10,957	10,731
Other Retiree Benefits
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[3]	5,096	3,259	$ 3,831
Other Retiree Benefits | Fair Value, Inputs, Level 1, 2 and 3 [Member]
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		4,948	3,101
Other Retiree Benefits | Cash and Cash Equivalents | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		111	5
Other Retiree Benefits | Company Stock | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[4]	4,836	3,092
Other Retiree Benefits | Other Assets | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount	[2]	1	4
Other Retiree Benefits | Other Assets | Fair Value Measured at Net Asset Value Per Share [Member]
ASSETS AT FAIR VALUE
Defined Benefit Plan, Plan Assets, Amount		$ 148	$ 158

[1] Primarily non-U.S.-based defined benefit retirement plans.

[2] The Company's other pension plan assets measured at fair value are generally classified as Level 3 within the fair value hierarchy. There are no material other pension plan asset balances classified as Level 1 or Level 2 within the fair value hierarchy.

[3] Primarily U.S.-based other postretirement benefit plans.

[4] Company stock is net of ESOP debt discussed below