ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - CHANGES IN AOCI AND RECLASSIFICATION OUT OF AOCI (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
Accumulated Other Comprehensive Income/(Loss)		$ (12,167)		$ (12,167)		$ (12,220)
OCI before Reclassifications	[1]			62
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			(11)
Other Comprehensive Income (Loss), Net of Tax		416	$ 302	51	$ (325)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				(2)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		11		11		13
OCI before Reclassifications	[1]			(2)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			0
Other Comprehensive Income (Loss), Net of Tax				(2)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]			0
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)		37		37		67
OCI before Reclassifications	[1]			(19)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			(11)
Other Comprehensive Income (Loss), Net of Tax				(30)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]			(9)
Reclassification from AOCI, Current Period, Tax	[2]			(1)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		$ (12,214)		(12,214)		$ (12,300)
OCI before Reclassifications	[1]			83
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			0
Other Comprehensive Income (Loss), Net of Tax				83
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				(2)
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]			(85)
Reclassification from AOCI, Current Period, Tax	[2]			$ 0

[1] Net of tax (benefit)/expense of $0, $(9) and $(85) for gains/losses on investment securities, postretirement benefit plans and foreign currency translation, respectively. Income tax effects within foreign currency translation include impacts from items such as net investment hedge transactions.

[2] Net of tax (benefit)/expense of $0, $(1) and $0 for gains/losses on investment securities, postretirement benefit plans and foreign currency translation, respectively.