TRADING ACCOUNT ASSETS AND LIABILITIES (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Trading account assets and Trading account liabilities
Trading account assets	$ 291,722	$ 320,929
Trading account liabilities	122,048	115,549
Mortgage-backed securities
Trading account assets and Trading account liabilities
Trading account assets	32,933	37,069
U.S. government-sponsored agency guaranteed
Trading account assets and Trading account liabilities
Trading account assets	26,833	31,160
Prime
Trading account assets and Trading account liabilities
Trading account assets	1,417	1,248
Alt-A
Trading account assets and Trading account liabilities
Trading account assets	765	801
Subprime
Trading account assets and Trading account liabilities
Trading account assets	1,326	812
Non-U.S. residential
Trading account assets and Trading account liabilities
Trading account assets	478	607
Commercial
Trading account assets and Trading account liabilities
Trading account assets	2,114	2,441
U.S. Treasury and federal agency securities
Trading account assets and Trading account liabilities
Trading account assets	21,039	20,356
U.S. Treasury
Trading account assets and Trading account liabilities
Trading account assets	18,091	17,472
Agency obligations
Trading account assets and Trading account liabilities
Trading account assets	2,948	2,884
State and municipal securities
Trading account assets and Trading account liabilities
Trading account assets	3,620	3,806
Foreign government securities
Trading account assets and Trading account liabilities
Trading account assets	79,618	89,239
Corporate
Trading account assets and Trading account liabilities
Trading account assets	31,024	35,224
Derivatives, assets
Trading account assets and Trading account liabilities
Trading account assets	51,749	54,620
Equity securities
Trading account assets and Trading account liabilities
Trading account assets	53,598	56,998
Asset-backed securities
Trading account assets and Trading account liabilities
Trading account assets	5,473	5,352
Other debt securities
Trading account assets and Trading account liabilities
Trading account assets	12,668	18,265
Securities sold, not yet purchased
Trading account assets and Trading account liabilities
Trading account liabilities	71,905	63,798
Derivatives, liabilities
Trading account assets and Trading account liabilities
Trading account liabilities	$ 50,143	$ 51,751