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, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
Accumulated Other Comprehensive Income/(Loss)		$ (15,156)		$ (15,156)		$ (14,749)
OCI before Reclassifications				(185)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				101
Other Comprehensive Income (Loss), Net of Tax		(22)	$ 121	(84)	$ 461
Adoption of New Accounting Standard_Reclass from AOCI to Retained Earnings				(326)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				(3)
Accumulated Other Comprehensive Income (Loss), Derivative Qualifying as Hedge, Excluded Component, Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		(3,065)		(3,065)		(3,246)
OCI before Reclassifications	[1]			199
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			0
Other Comprehensive Income (Loss), Net of Tax				199
Adoption of New Accounting Standard_Reclass from AOCI to Retained Earnings				(18)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		(120)		(120)		(173)
OCI before Reclassifications	[1]			54
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			(1)
Other Comprehensive Income (Loss), Net of Tax				53
Adoption of New Accounting Standard_Reclass from AOCI to Retained Earnings				0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Accumulated Other Comprehensive Income/(Loss)		(4,116)		(4,116)		(4,058)
OCI before Reclassifications	[1]			149
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[2]			101
Other Comprehensive Income (Loss), Net of Tax				250
Adoption of New Accounting Standard_Reclass from AOCI to Retained Earnings				(308)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				0
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income/(Loss)		$ (7,855)		(7,855)		$ (7,272)
OCI before Reclassifications				(587)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				1
Other Comprehensive Income (Loss), Net of Tax				(586)
Adoption of New Accounting Standard_Reclass from AOCI to Retained Earnings				0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest				$ (3)

[1] Net of tax expense/(benefit) of $61, $0 and $38 for gains/losses on hedges, investment securities and pension and other retiree benefit items, respectively.

[2] Net of tax expense/(benefit) of $0, $0 and $32 for gains/losses on hedges, investment securities and pension and other retiree benefit items, respectively.