SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 272,676	$ 246,788
Gross amounts offset on the Consolidated Balance Sheet	102,920	87,424
Net amounts of assets included on the Consolidated Balance Sheet	169,756	159,364
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	133,878	124,557
Net amounts	35,878	34,807
Deposits paid for securities borrowed
Gross amounts of recognized assets	94,342	111,320
Gross amounts offset on the Consolidated Balance Sheet	2,973	0
Net amounts of assets included on the Consolidated Balance Sheet	91,369	111,320
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	25,456	35,766
Net amounts	65,913	75,554
Total
Gross amounts of recognized assets	367,018	358,108
Gross amounts offset on the Consolidated Balance Sheet	105,893	87,424
Net amounts of assets included on the Consolidated Balance Sheet	261,125	270,684
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	159,334	160,323
Net amounts	101,791	110,361
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	283,795	253,514
Gross amounts offset on the Consolidated Balance Sheet	102,920	87,424
Net amounts of liabilities included on the Consolidated Balance Sheet	180,875	166,090
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	92,860	82,823
Net amounts	88,015	83,267
Deposits received for securities loaned
Gross amounts of recognized liabilities	17,145	11,678
Gross amounts offset on the Consolidated Balance Sheet	2,973	0
Net amounts of liabilities included on the Consolidated Balance Sheet	14,172	11,678
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	4,629	3,415
Net amounts	9,543	8,263
Total
Gross amounts of recognized liabilities	300,940	265,192
Gross amounts offset on the Consolidated Balance Sheet	105,893	87,424
Net amounts of liabilities included on the Consolidated Balance Sheet	195,047	177,768
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	97,489	86,238
Net amounts	$ 97,558	$ 91,530