POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - RECONCILIATION OF BENEFIT OBLIGATIONS AND PLAN ASSETS (Details) - USD ($) $ in Millions		12 Months Ended
		Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2018
Pension Plan
CHANGE IN BENEFIT OBLIGATION
Defined Benefit Plan, Benefit Obligation, Beginning of Year	[1],[2]	$ 17,037		$ 15,658
Defined Benefit Plan, Service Cost		247	[2]	259	[2]	$ 280
Defined Benefit Plan, Interest Cost		276	[2]	339	[2]	348
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	[2]	11		12
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	[2]	3		9
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	[2]	951		1,587
Defined Benefit Plan, Acquisitions (Divestitures), Benefit Obligation	[2]	0		49
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	[2]	11		13
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	[2]	(218)		(283)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	[2]	(557)		(606)
Defined Benefit Plan, Benefit Obligation, End of Year	[1],[2]	17,761		17,037		15,658
CHANGE IN PLAN ASSETS
Defined Benefit Plan, Fair Value of Plan Assets, Beginning of Year	[2]	11,382		11,267
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	[2]	664		739
Defined Benefit Plan Acquisitions Divestitures Plan Assets	[2]	0		4
Defined Benefit Plan, Plan Assets, Contributions by Employer	[2]	180		178
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant	[2]	11		12
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	[2]	(196)		(212)
Defined Benefit Plan, ESOP Debt Servicing	[2],[3]	0		0
Defined Benefit Plan, Plan Assets, Benefits Paid	[2]	(557)		(606)
Defined Benefit Plan, Fair Value of Plan Assets, End of Year	[2]	11,484		11,382		11,267
Defined Benefit Plan, Funded (Unfunded) Status of Plan	[2]	(6,277)		(5,655)
Other Retiree Benefits
CHANGE IN BENEFIT OBLIGATION
Defined Benefit Plan, Benefit Obligation, Beginning of Year	[1],[4]	4,964		4,778
Defined Benefit Plan, Service Cost		100	[4]	101	[4]	112
Defined Benefit Plan, Interest Cost		160	[4]	187	[4]	177
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	[4]	74		76
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	[4]	(136)		0
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	[4]	(85)		37
Defined Benefit Plan, Acquisitions (Divestitures), Benefit Obligation	[4]	0		0
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	[4]	2		8
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	[4]	(64)		20
Defined Benefit Plan, Benefit Obligation, Benefits Paid	[4]	(245)		(243)
Defined Benefit Plan, Benefit Obligation, End of Year	[1],[4]	4,770		4,964		4,778
CHANGE IN PLAN ASSETS
Defined Benefit Plan, Fair Value of Plan Assets, Beginning of Year	[4]	5,096		3,259
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	[4]	595		1,918
Defined Benefit Plan Acquisitions Divestitures Plan Assets	[4]	0		0
Defined Benefit Plan, Plan Assets, Contributions by Employer	[4]	33		31
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant	[4]	74		76
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	[4]	2		(1)
Defined Benefit Plan, ESOP Debt Servicing	[3],[4]	63		56
Defined Benefit Plan, Plan Assets, Benefits Paid	[4]	(245)		(243)
Defined Benefit Plan, Fair Value of Plan Assets, End of Year	[4]	5,618		5,096		$ 3,259
Defined Benefit Plan, Funded (Unfunded) Status of Plan	[4]	$ 848		$ 132

[1] For the pension benefit plans, the benefit obligation is the projected benefit obligation. For other retiree benefit plans, the benefit obligation is the accumulated postretirement benefit obligation.

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

[3] Represents the net impact of ESOP debt service requirements, which is netted against plan assets for other retiree benefits.

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