SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Variable Interest Entity
Cash	$ 28,906	$ 26,349	$ 25,308
Trading account assets	342,914	375,079
Investments	500,849	447,359
Total loans, net of allowance	647,049	650,927
Increase in other assets	123,947	110,683
Total assets	2,361,876	2,260,090
Unconsolidated VIEs
Variable Interest Entity
Cash	0	0
Trading account assets	1,400	2,000
Investments	9,300	10,600
Total loans, net of allowance	32,300	29,300
Increase in other assets	900	300
Total assets	$ 43,900	$ 42,200