POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - COMPONENTS OF NET PERIODIC BENEFIT COST (Details) - USD ($) $ in Millions		12 Months Ended
		Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2017
Pension Plan
AMOUNTS RECOGNIZED IN NET PERIODIC BENEFIT COST
Defined Benefit Plan, Service Cost	[2]	$ 259	[1]	$ 280	[1]	$ 310
Defined Benefit Plan, Interest Cost		339	[1]	348	[1]	300
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(732)		(751)		(675)
Defined Benefit Plan, Amortization of Gain (Loss)		225		295		375
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		26		28		28
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		9		0	[3]	186
Defined Benefit Plan, Other Cost (Credit)		13		8		4
Defined Benefit Plan Gross Periodic Benefit Cost		139		208		528
Employee Stock Ownership Plan (ESOP), Dividends on ESOP Preferred Stock		0		0		0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		139		208		528
CHANGE IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN AOCI
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax		1,580		(524)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax		9		12
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		(225)		(295)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax		(26)		(28)
Other Comprehensive Income Defined Benefit Plan Settlement And Curtailment Cost Before Tax		(9)		0
Other Comprehensive Income, Defined Benefit Plan, Currency Translation and Other, Before Tax		(84)		73
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax		1,245		(762)
Defined Benefit Plans, Amount Recognized In Periodic Benefit Cost And Accumulated Other Comprehensive Income		1,384		(554)
Other Retiree Benefits
AMOUNTS RECOGNIZED IN NET PERIODIC BENEFIT COST
Defined Benefit Plan, Service Cost	[2]	101	[4]	112	[4]	133
Defined Benefit Plan, Interest Cost		187	[4]	177	[4]	175
Defined Benefit Plan, Expected Return (Loss) on Plan Assets		(447)		(451)		(431)
Defined Benefit Plan, Amortization of Gain (Loss)		66		69		122
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)		(48)		(41)		(45)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		0		0	[3]	16
Defined Benefit Plan, Other Cost (Credit)		8		7	[3]	21
Defined Benefit Plan Gross Periodic Benefit Cost		(133)		(127)		(9)
Employee Stock Ownership Plan (ESOP), Dividends on ESOP Preferred Stock		(28)		(37)		(45)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		(161)		(164)		$ (54)
CHANGE IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN AOCI
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax		(1,434)		624
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax		0		(231)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		(66)		(69)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax		48		41
Other Comprehensive Income Defined Benefit Plan Settlement And Curtailment Cost Before Tax		0		0
Other Comprehensive Income, Defined Benefit Plan, Currency Translation and Other, Before Tax		14		(3)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax		(1,438)		362
Defined Benefit Plans, Amount Recognized In Periodic Benefit Cost And Accumulated Other Comprehensive Income		$ (1,599)		$ 198

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

[2] Service cost includes amounts related to discontinued operations in fiscal year ended June 30, 2017, which are not material.

[3] For fiscal year ended June 30, 2017, amortization of net actuarial loss/prior service cost due to settlement and curtailments and $18 of the special termination benefits are included in Net earnings from discontinued operations.

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