TRADING ACCOUNT ASSETS AND LIABILITIES (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Trading account assets and Trading account liabilities
Trading account assets	$ 310,246	$ 291,734
Trading account liabilities	128,818	126,082
Mortgage-backed securities
Trading account assets and Trading account liabilities
Trading account assets	36,344	32,739
U.S. government-sponsored agency guaranteed
Trading account assets and Trading account liabilities
Trading account assets	30,747	27,535
Prime
Trading account assets and Trading account liabilities
Trading account assets	1,314	877
Alt-A
Trading account assets and Trading account liabilities
Trading account assets	825	609
Subprime
Trading account assets and Trading account liabilities
Trading account assets	788	989
Non-U.S. residential
Trading account assets and Trading account liabilities
Trading account assets	404	396
Commercial
Trading account assets and Trading account liabilities
Trading account assets	2,266	2,333
U.S. Treasury and federal agency securities
Trading account assets and Trading account liabilities
Trading account assets	22,784	19,399
U.S. Treasury
Trading account assets and Trading account liabilities
Trading account assets	20,236	18,227
Agency obligations
Trading account assets and Trading account liabilities
Trading account assets	2,548	1,172
State and municipal securities
Trading account assets and Trading account liabilities
Trading account assets	6,649	5,364
Foreign government securities
Trading account assets and Trading account liabilities
Trading account assets	84,157	79,551
Corporate
Trading account assets and Trading account liabilities
Trading account assets	34,898	37,026
Derivatives, assets
Trading account assets and Trading account liabilities
Trading account assets	60,776	62,327
Equity securities
Trading account assets and Trading account liabilities
Trading account assets	42,250	33,230
Asset-backed securities
Trading account assets and Trading account liabilities
Trading account assets	5,945	7,071
Other debt securities
Trading account assets and Trading account liabilities
Trading account assets	16,443	15,027
Securities sold, not yet purchased
Trading account assets and Trading account liabilities
Trading account liabilities	70,559	69,809
Derivatives, liabilities
Trading account assets and Trading account liabilities
Trading account liabilities	$ 58,259	$ 56,273