FEDERAL FUNDS, SECURITIES BORROWED, LOANED AND SUBJECT TO REPURCHASE AGREEMENTS - Offsetting (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Securities purchased under agreements to resell
Gross amounts of recognized assets	$ 177,767	$ 176,167
Gross amounts offset on the Consolidated Balance Sheet	55,948	56,390
Net amounts of assets included on the Consolidated Balance Sheet	121,819	119,777
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	87,866	92,039
Net amounts	33,953	27,738
Deposits paid for securities borrowed
Gross amounts of recognized assets	103,274	99,873
Net amounts of assets included on the Consolidated Balance Sheet	103,274	99,873
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	16,291	16,619
Net amounts	86,983	83,254
Total
Total	281,041	276,040
Gross amounts offset on the Consolidated Balance Sheet	55,948	56,390
Net amounts of assets included on the Consolidated Balance Sheet	225,093	219,650
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	104,157	108,658
Net amounts	120,936	110,992
Securities sold under agreements to repurchase
Gross amounts of recognized liabilities	196,215	188,040
Gross amounts offset on the Consolidated Balance Sheet	55,948	56,390
Net amounts of liabilities included on the Consolidated Balance Sheet	140,267	131,650
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	67,435	60,641
Net amounts	72,832	71,009
Deposits received for securities loaned
Gross amounts of recognized liabilities	16,565	14,657
Net amounts of liabilities included on the Consolidated Balance Sheet	16,565	14,657
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	3,843	3,226
Net amounts	12,722	11,431
Total
Gross amounts of recognized liabilities	212,780	202,697
Gross amounts offset on the Consolidated Balance Sheet	55,948	56,390
Net amounts of liabilities included on the Consolidated Balance Sheet	156,832	146,307
Amounts not offset on the Consolidated Balance Sheet but eligible for offsetting upon counterparty default	71,278	63,867
Net amounts	$ 85,554	$ 82,440