FEDERAL FUNDS, SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 194,788	$ 176,167
Gross amounts offset on the Consolidated Balance Sheet	58,821	56,390
Net amounts of assets included on the Consolidated Balance Sheet	135,967	119,777
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	105,941	92,039
Net amounts	30,026	27,738
Deposits paid for securities borrowed
Gross amounts of recognized assets	100,037	99,873
Net amounts of assets included on the Consolidated Balance Sheet	100,037	99,873
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	15,835	16,619
Net amounts	84,202	83,254
Total
Total	294,825	276,040
Gross amounts offset on the Consolidated Balance Sheet	58,821	56,390
Net amounts of assets included on the Consolidated Balance Sheet	236,004	219,650
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	121,776	108,658
Net amounts	114,228	110,992
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	194,728	188,040
Gross amounts offset on the Consolidated Balance Sheet	58,821	56,390
Net amounts of liabilities included on the Consolidated Balance Sheet	135,907	131,650
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	65,748	60,641
Net amounts	70,159	71,009
Deposits received for securities loaned
Gross amounts of recognized liabilities	16,845	14,657
Net amounts of liabilities included on the Consolidated Balance Sheet	16,845	14,657
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	2,871	3,226
Net amounts	13,974	11,431
Total
Gross amounts of recognized liabilities	211,573	202,697
Gross amounts offset on the Consolidated Balance Sheet	58,821	56,390
Net amounts of liabilities included on the Consolidated Balance Sheet	152,752	146,307
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	68,619	63,867
Net amounts	$ 84,133	$ 82,440