TRADING ACCOUNT ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Trading account assets and Trading account liabilities
Trading account assets	$ 266,946	$ 296,786
Trading account liabilities	125,981	139,036
Securities sold, not yet purchased
Trading account assets and Trading account liabilities
Trading account liabilities	63,733	70,944
Derivatives, liabilities
Trading account assets and Trading account liabilities
Trading account liabilities	62,248	68,092
Derivatives, assets
Trading account assets and Trading account liabilities
Trading account assets	60,871	67,957
Mortgage-backed securities - U.S. agency-sponsored
Trading account assets and Trading account liabilities
Trading account assets	26,753	27,053
Mortgage-backed securities - Prime
Trading account assets and Trading account liabilities
Trading account assets	1,316	1,271
Mortgage-backed securities - Alt-A
Trading account assets and Trading account liabilities
Trading account assets	580	709
Mortgage-backed securities - Subprime
Trading account assets and Trading account liabilities
Trading account assets	840	1,382
Mortgage-backed securities - Non-U.S. residential
Trading account assets and Trading account liabilities
Trading account assets	663	1,476
Mortgage-backed securities - Commercial
Trading account assets and Trading account liabilities
Trading account assets	2,787	4,343
Mortgage-backed securities
Trading account assets and Trading account liabilities
Trading account assets	32,939	36,234
U.S. Treasury and federal agency securities
Trading account assets and Trading account liabilities
Trading account assets	27,763	20,474
U.S. Treasury
Trading account assets and Trading account liabilities
Trading account assets	26,417	18,906
Agency obligations
Trading account assets and Trading account liabilities
Trading account assets	1,346	1,568
State and municipal securities
Trading account assets and Trading account liabilities
Trading account assets	3,824	3,402
Foreign government securities
Trading account assets and Trading account liabilities
Trading account assets	57,676	64,937
Corporate
Trading account assets and Trading account liabilities
Trading account assets	18,012	27,797
Equity securities
Trading account assets and Trading account liabilities
Trading account assets	48,181	57,846
Asset-backed securities
Trading account assets and Trading account liabilities
Trading account assets	5,017	4,546
Other trading assets
Trading account assets and Trading account liabilities
Trading account assets	$ 12,663	$ 13,593