SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Variable Interest Entity
Cash	$ 26,204	$ 26,349	$ 23,755
Trading account assets	360,659	375,079
Investments	472,959	447,359
Total loans, net of allowance	644,350	650,927
Increase in other assets	109,433	110,683
Total assets	2,314,266	2,260,090
Unconsolidated VIEs
Variable Interest Entity
Cash	0	0
Trading account assets	1,800	2,000
Investments	10,200	10,600
Total loans, net of allowance	31,300	29,300
Increase in other assets	400	300
Total assets	$ 43,700	$ 42,200