SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 292,088	$ 246,788
Gross amounts offset on the Consolidated Balance Sheet	128,302	87,424
Net amounts of assets included on the Consolidated Balance Sheet	163,786	159,364
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	128,476	124,557
Net amounts	35,310	34,807
Deposits paid for securities borrowed
Gross amounts of recognized assets	95,983	111,320
Net amounts of assets included on the Consolidated Balance Sheet	95,983	111,320
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	26,429	35,766
Net amounts	69,554	75,554
Total
Gross amounts of recognized assets	388,071	358,108
Gross amounts offset on the Consolidated Balance Sheet	128,302	87,424
Net amounts of assets included on the Consolidated Balance Sheet	259,769	270,684
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	154,905	160,323
Net amounts	104,864	110,361
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	297,163	253,514
Gross amounts offset on the Consolidated Balance Sheet	128,302	87,424
Net amounts of liabilities included on the Consolidated Balance Sheet	168,861	166,090
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	87,803	82,823
Net amounts	81,058	83,267
Deposits received for securities loaned
Gross amounts of recognized liabilities	12,272	11,678
Net amounts of liabilities included on the Consolidated Balance Sheet	12,272	11,678
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	2,551	3,415
Net amounts	9,721	8,263
Total
Gross amounts of recognized liabilities	309,435	265,192
Gross amounts offset on the Consolidated Balance Sheet	128,302	87,424
Net amounts of liabilities included on the Consolidated Balance Sheet	181,133	177,768
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	90,354	86,238
Net amounts	$ 90,779	$ 91,530