SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Carrying Amounts and Classifications of Consolidated Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity
Cash and due from banks	$ 23,775	$ 23,043	$ 20,900	$ 32,108
Trading account assets	251,556	243,925
Investments	352,290	353,304
Total loans, net of allowance	654,679	612,309
Other assets	105,160	128,008
Total assets	1,842,465	1,792,077
Significant unconsolidated VIE assets
Variable Interest Entity
Cash and due from banks	0	100
Trading account assets	8,500	8,000
Investments	4,400	4,400
Total loans, net of allowance	22,200	18,800
Other assets	500	1,500
Total assets	$ 35,600	$ 32,800