COMMISSIONS AND FEES; ADMINISTRATION AND OTHER FIDUCIARY FEES - Administration and Other Fiduciary Fees (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Commissions and fees
Total administration and other fiduciary fees	$ 1,037	$ 896
Custody fees
Commissions and fees
Total administration and other fiduciary fees	514	444
Fiduciary fees
Commissions and fees
Total administration and other fiduciary fees	392	310
Guarantee fees
Commissions and fees
Total administration and other fiduciary fees	131	142
Administration and other fiduciary fees
Commissions and fees
Total administration and other fiduciary fees	1,037	896
Revenue not accounted for under ASC 606, revenue from contracts with customers	$ 131	$ 142