SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 320,598	$ 281,274
Gross amounts offset on the Consolidated Balance Sheet	115,215	111,400
Net amounts of assets included on the Consolidated Balance Sheet	205,383	169,874
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	166,638	134,150
Net amounts	38,745	35,724
Deposits paid for securities borrowed
Gross amounts of recognized assets	89,622	90,047
Gross amounts offset on the Consolidated Balance Sheet	5,643	8,599
Net amounts of assets included on the Consolidated Balance Sheet	83,979	81,448
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	19,958	27,067
Net amounts	64,021	54,381
Total
Gross amounts of recognized assets	410,220	371,321
Gross amounts offset on the Consolidated Balance Sheet	120,858	119,999
Net amounts of assets included on the Consolidated Balance Sheet	289,362	251,322
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	186,596	161,217
Net amounts	102,766	90,105
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	309,749	266,564
Gross amounts offset on the Consolidated Balance Sheet	115,215	111,400
Net amounts of liabilities included on the Consolidated Balance Sheet	194,534	155,164
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	99,500	91,034
Net amounts	95,034	64,130
Deposits received for securities loaned
Gross amounts of recognized liabilities	18,336	19,774
Gross amounts offset on the Consolidated Balance Sheet	5,643	8,599
Net amounts of liabilities included on the Consolidated Balance Sheet	12,693	11,175
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	3,978	3,138
Net amounts	8,715	8,037
Total
Gross amounts of recognized liabilities	328,085	286,338
Gross amounts offset on the Consolidated Balance Sheet	120,858	119,999
Net amounts of liabilities included on the Consolidated Balance Sheet	207,227	166,339
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	103,478	94,172
Net amounts	$ 103,749	$ 72,167