ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - CHANGES IN AOCI AND RECLASSIFICATION OUT OF AOCI (Details) - USD ($) $ in Millions		3 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021
Accumulated Other Comprehensive Income/(Loss)		$ (14,062)		$ (13,744)
OCI before Reclassifications	[1]	(380)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]	62
Other Comprehensive Income (Loss), Net of Tax		(318)	$ 289
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest		0
Accumulated Other Comprehensive Income (Loss), Derivative Qualifying as Hedge, Excluded Component, Including Portion Attributable to Noncontrolling Interest [Member]
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]	120
Reclassification from AOCI, Current Period, Tax	[2]	0
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		20		15
OCI before Reclassifications	[1]	5
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]
Other Comprehensive Income (Loss), Net of Tax		5
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest		0
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]	1
Reclassification from AOCI, Current Period, Tax	[2]	0
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income/(Loss)		(2,821)		(2,963)
OCI before Reclassifications	[1]	80
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]	62
Other Comprehensive Income (Loss), Net of Tax		142
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest		0
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]	29
Reclassification from AOCI, Current Period, Tax	[2]	20
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		(11,261)		$ (10,796)
OCI before Reclassifications	[1]	(465)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]
Other Comprehensive Income (Loss), Net of Tax		(465)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest		$ 0

[1] Net of tax expense/(benefit) of $1, $29 and $120 for gains/losses on investment securities, postretirement benefit items and foreign currency translation, respectively. Income tax effects within cumulative translation include impacts from items such as net investment hedge transactions. Foreign cumulative translation is not adjusted for income taxes related to permanent investments in international subsidiaries.

[2] Net of tax expense/(benefit) of $0, $20 and $0 for gains/losses on investment securities, postretirement benefit items and foreign currency translation, respectively.