SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 304,427	$ 281,274
Gross amounts offset on the Consolidated Balance Sheet	125,497	111,400
Net amounts of assets included on the Consolidated Balance Sheet	178,930	169,874
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	142,194	134,150
Net amounts	36,736	35,724
Deposits paid for securities borrowed
Gross amounts of recognized assets	87,669	90,047
Gross amounts offset on the Consolidated Balance Sheet	4,063	8,599
Net amounts of assets included on the Consolidated Balance Sheet	83,606	81,448
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	27,015	27,067
Net amounts	56,591	54,381
Total
Gross amounts of recognized assets	392,096	371,321
Gross amounts offset on the Consolidated Balance Sheet	129,560	119,999
Net amounts of assets included on the Consolidated Balance Sheet	262,536	251,322
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	169,209	161,217
Net amounts	93,327	90,105
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	339,022	266,564
Gross amounts offset on the Consolidated Balance Sheet	125,497	111,400
Net amounts of liabilities included on the Consolidated Balance Sheet	213,525	155,164
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	125,995	91,034
Net amounts	87,530	64,130
Deposits received for securities loaned
Gross amounts of recognized liabilities	12,862	19,774
Gross amounts offset on the Consolidated Balance Sheet	4,063	8,599
Net amounts of liabilities included on the Consolidated Balance Sheet	8,799	11,175
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	3,109	3,138
Net amounts	5,690	8,037
Total
Gross amounts of recognized liabilities	351,884	286,338
Gross amounts offset on the Consolidated Balance Sheet	129,560	119,999
Net amounts of liabilities included on the Consolidated Balance Sheet	222,324	166,339
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	129,104	94,172
Net amounts	$ 93,220	$ 72,167