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, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Accumulated Other Comprehensive Income/(Loss)		$ (14,942)		$ (14,942)		$ (14,936)
OCI before Reclassifications	[1]			(158)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			146
Other Comprehensive Income (Loss), Net of Tax		354	$ (22)	(12)	$ (84)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				(6)
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]			50
Reclassification from AOCI, Current Period, Tax	[2]			0
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest [Member]
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]			(1)
Accumulated Other Comprehensive Income/(Loss)		5		5		11
OCI before Reclassifications	[1]			(4)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			(2)
Other Comprehensive Income (Loss), Net of Tax				(6)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Reclassification from AOCI, Current Period, Tax	[2]			0
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss) before Reclassifications, Tax	[1]			13
Accumulated Other Comprehensive Income/(Loss)		(4,056)		(4,056)		(4,198)
OCI before Reclassifications	[1]			(6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			148
Other Comprehensive Income (Loss), Net of Tax				142
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Reclassification from AOCI, Current Period, Tax	[2]			44
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		$ (10,891)		(10,891)		$ (10,749)
OCI before Reclassifications	[1]			(148)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			0
Other Comprehensive Income (Loss), Net of Tax				(148)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				$ (6)

[1] Net of tax expense/(benefit) of $(1), $13 and $50 for gains/losses on investment securities, pension and other retiree benefit items and foreign currency translation, respectively.

[2] Net of tax expense/(benefit) of $0, $44 and $0 for gains/losses on investment securities, pension and other retiree benefit items and foreign currency translation, respectively.