SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Variable Interest Entity
Cash and due from banks	$ 24,448	$ 23,645	$ 21,850
Trading account assets	286,511	256,117
Investments	349,281	358,607
Total loans, net of allowance	670,017	671,881
Other	110,483	109,273
Total assets	1,958,413	1,917,383
Unconsolidated VIEs
Variable Interest Entity
Cash and due from banks	0	0
Trading account assets	3,400	3,000
Investments	10,300	10,700
Total loans, net of allowance	25,700	24,500
Other	500	500
Total assets	$ 39,900	$ 38,700