COMMISSIONS AND FEES; ADMINISTRATION AND OTHER FIDUCIARY FEES - Administration and Other Fiduciary Fees (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Commissions and fees
Total administration and other fiduciary fees	$ 989	$ 1,023	$ 1,885	$ 1,989
Custody fees
Commissions and fees
Total administration and other fiduciary fees	510	530	955	1,002
Custody fees | ICG
Commissions and fees
Total administration and other fiduciary fees	485	506	902	952
Custody fees | PBWM
Commissions and fees
Total administration and other fiduciary fees	22	22	42	45
Custody fees | Legacy Franchises
Commissions and fees
Total administration and other fiduciary fees	3	2	11	5
Fiduciary fees
Commissions and fees
Total administration and other fiduciary fees	344	343	654	693
Fiduciary fees | ICG
Commissions and fees
Total administration and other fiduciary fees	69	68	144	133
Fiduciary fees | PBWM
Commissions and fees
Total administration and other fiduciary fees	185	196	338	401
Fiduciary fees | Legacy Franchises
Commissions and fees
Total administration and other fiduciary fees	90	79	172	159
Guarantee fees
Commissions and fees
Total administration and other fiduciary fees	135	150	276	294
Guarantee fees | ICG
Commissions and fees
Total administration and other fiduciary fees	126	134	258	266
Guarantee fees | PBWM
Commissions and fees
Total administration and other fiduciary fees	7	14	15	24
Guarantee fees | Legacy Franchises
Commissions and fees
Total administration and other fiduciary fees	1	2	3	4
Administration and other fiduciary fees
Commissions and fees
Total administration and other fiduciary fees	989	1,023	1,885	1,989
Revenue not accounted for under ASC 606, revenue from contracts with customers	135	150	276	294
Administration and other fiduciary fees | ICG
Commissions and fees
Total administration and other fiduciary fees	680	708	1,304	1,351
Administration and other fiduciary fees | PBWM
Commissions and fees
Total administration and other fiduciary fees	214	232	395	470
Administration and other fiduciary fees | Legacy Franchises
Commissions and fees
Total administration and other fiduciary fees	$ 94	$ 83	$ 186	$ 168