FEDERAL FUNDS, SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 246,788	$ 204,460
Gross amounts offset on the Consolidated Balance Sheet	87,424	73,476
Net amounts of assets included on the Consolidated Balance Sheet	159,364	130,984
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	124,557	103,022
Net amounts	34,807	27,962
Deposits paid for securities borrowed
Gross amounts of recognized assets	111,320	101,494
Net amounts of assets included on the Consolidated Balance Sheet	111,320	101,494
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	35,766	22,271
Net amounts	75,554	79,223
Total
Total	358,108	305,954
Gross amounts offset on the Consolidated Balance Sheet	87,424	73,476
Net amounts of assets included on the Consolidated Balance Sheet	270,684	232,478
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	160,323	125,293
Net amounts	110,361	107,185
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	253,514	216,122
Gross amounts offset on the Consolidated Balance Sheet	87,424	73,476
Net amounts of liabilities included on the Consolidated Balance Sheet	166,090	142,646
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	82,823	73,716
Net amounts	83,267	68,930
Deposits received for securities loaned
Gross amounts of recognized liabilities	11,678	13,305
Net amounts of liabilities included on the Consolidated Balance Sheet	11,678	13,305
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	3,415	4,079
Net amounts	8,263	9,226
Total
Gross amounts of recognized liabilities	265,192	229,427
Gross amounts offset on the Consolidated Balance Sheet	87,424	73,476
Net amounts of liabilities included on the Consolidated Balance Sheet	177,768	155,951
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	86,238	77,795
Net amounts	$ 91,530	$ 78,156