SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity
Cash and due from banks	$ 26,349	$ 23,967	$ 23,645
Trading account assets	375,079	276,140
Investments	447,359	368,563
Total loans, net of allowance	650,927	686,700
Other assets	110,683	107,709
Total assets	2,260,090	1,951,158
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Cash and due from banks	0	0
Trading account assets	2,000	2,600
Investments	10,600	9,900
Total loans, net of allowance	29,300	26,700
Other assets	300	500
Total assets	$ 42,200	$ 39,700