ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - CHANGES IN AOCI AND RECLASSIFICATION OUT OF AOCI (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Mar. 31, 2023
Mar. 31, 2022
Jun. 30, 2022
Accumulated Other Comprehensive Income/(Loss) $ (12,266)   $ (12,266)   $ (12,189)
OCI before Reclassifications [1]     (98)    
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [2]     14    
Other Comprehensive Income (Loss), Net of Tax 241 $ 112 (84) $ 292  
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest     (7)    
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest [Member]          
Accumulated Other Comprehensive Income/(Loss) 18   18   20
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        
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) 19   19   27
OCI before Reclassifications [1]     (22)    
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [2]     14    
Other Comprehensive Income (Loss), Net of Tax     (8)    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest     0    
Other Comprehensive Income (Loss) before Reclassifications, Tax [1]     (13)    
Reclassification from AOCI, Current Period, Tax [2]     7    
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]          
Accumulated Other Comprehensive Income/(Loss) $ (12,303)   (12,303)   $ (12,236)
OCI before Reclassifications [1]     (74)    
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [2]     0    
Other Comprehensive Income (Loss), Net of Tax     (74)    
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest     (7)    
Other Comprehensive Income (Loss) before Reclassifications, Tax [1]     (230)    
Reclassification from AOCI, Current Period, Tax [2]     $ 0    
[1] Net of tax (benefit)/expense of $(1), $(13) and $(230) 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, $7 and $0 for gains/losses on investment securities, postretirement benefit plans and foreign currency translation, respectively.