SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Securities (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities purchased under agreements to resell	$ 242,379	$ 192,950
Securities borrowed	78,976	81,115
Total, net	321,355	274,065
Allowance for credit losses on securities purchased and borrowed	(8)	(3)
Total, net of allowance	321,347	274,062
Securities sold under agreements to repurchase	327,517	239,767
Securities loaned	22,209	14,988
Total, net	349,726	254,755
Securities-for-securities lending transactions	$ 4,900	$ 5,200