FEDERAL FUNDS, SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 176,900	$ 180,318
Gross amounts offset on the Consolidated Balance Sheet	46,771	56,339
Net amounts of assets included on the Consolidated Balance Sheet	130,129	123,979
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	97,314	94,353
Net amounts	32,815	29,626
Deposits paid for securities borrowed
Gross amounts of recognized assets	101,566	118,591
Net amounts of assets included on the Consolidated Balance Sheet	101,566	118,591
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	16,919	15,139
Net amounts	84,647	103,452
Total
Total	278,466	298,909
Gross amounts offset on the Consolidated Balance Sheet	46,771	56,339
Net amounts of assets included on the Consolidated Balance Sheet	231,695	242,570
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	114,233	109,492
Net amounts	117,462	133,078
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	195,318	203,543
Gross amounts offset on the Consolidated Balance Sheet	46,771	56,339
Net amounts of liabilities included on the Consolidated Balance Sheet	148,547	147,204
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	69,502	72,928
Net amounts	79,045	74,276
Deposits received for securities loaned
Gross amounts of recognized liabilities	19,924	25,900
Net amounts of liabilities included on the Consolidated Balance Sheet	19,924	25,900
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	4,725	5,190
Net amounts	15,199	20,710
Total
Gross amounts of recognized liabilities	215,242	229,443
Gross amounts offset on the Consolidated Balance Sheet	46,771	56,339
Net amounts of liabilities included on the Consolidated Balance Sheet	168,471	173,104
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	74,227	78,118
Net amounts	$ 94,244	$ 94,986