INVESTMENTS (Details 4) (USD $)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Reclassification of debt securities from held-to-maturity to trading account assets	Dec. 31, 2011 Reclassification of debt securities from held-to-maturity to trading account assets	Jun. 30, 2012 Mortgage-backed securities	Dec. 31, 2011 Mortgage-backed securities	Jun. 30, 2012 Prime	Dec. 31, 2011 Prime	Jun. 30, 2012 Alt-A	Dec. 31, 2011 Alt-A	Jun. 30, 2012 Subprime	Dec. 31, 2011 Subprime	Jun. 30, 2012 Non-U.S. residential	Dec. 31, 2011 Non-U.S. residential	Jun. 30, 2012 Commercial	Dec. 31, 2011 Commercial	Jun. 30, 2012 State and municipal securities	Dec. 31, 2011 State and municipal securities	Jun. 30, 2012 Foreign government	Jun. 30, 2012 Corporate	Dec. 31, 2011 Corporate	Jun. 30, 2012 Asset-backed securities	Dec. 31, 2011 Asset-backed securities
Debt Securities Held-to-maturity
Amortized cost	$ 13,270,000,000	$ 13,759,000,000			$ 7,346,000,000	$ 9,475,000,000	$ 322,000,000	$ 360,000,000	$ 3,532,000,000	$ 4,732,000,000	$ 252,000,000	$ 383,000,000	$ 2,768,000,000	$ 3,487,000,000	$ 472,000,000	$ 513,000,000	$ 1,332,000,000	$ 1,422,000,000	$ 2,746,000,000	$ 930,000,000	$ 1,862,000,000	$ 916,000,000	$ 1,000,000,000
Net unrealized loss recognized in AOCI	1,921,000,000	2,276,000,000			1,679,000,000	2,045,000,000	57,000,000	73,000,000	1,138,000,000	1,404,000,000	45,000,000	47,000,000	438,000,000	520,000,000	1,000,000	1,000,000	85,000,000	95,000,000		124,000,000	113,000,000	33,000,000	23,000,000
Carrying value	11,349,000,000	11,483,000,000			5,667,000,000	7,430,000,000	265,000,000	287,000,000	2,394,000,000	3,328,000,000	207,000,000	336,000,000	2,330,000,000	2,967,000,000	471,000,000	512,000,000	1,247,000,000	1,327,000,000	2,746,000,000	806,000,000	1,749,000,000	883,000,000	977,000,000
Gross unrecognized gains	448,000,000	182,000,000			334,000,000	105,000,000	21,000,000	21,000,000	264,000,000	20,000,000	5,000,000	1,000,000	41,000,000	59,000,000	3,000,000	4,000,000	94,000,000	68,000,000	10,000,000	3,000,000		7,000,000	9,000,000
Gross unrecognized losses	614,000,000	1,165,000,000			513,000,000	752,000,000	21,000,000	20,000,000	215,000,000	319,000,000	28,000,000	71,000,000	220,000,000	290,000,000	29,000,000	52,000,000	49,000,000	72,000,000		4,000,000	254,000,000	48,000,000	87,000,000
Fair value	11,183,000,000	10,500,000,000			5,488,000,000	6,783,000,000	265,000,000	288,000,000	2,443,000,000	3,029,000,000	184,000,000	266,000,000	2,151,000,000	2,736,000,000	445,000,000	464,000,000	1,292,000,000	1,323,000,000	2,756,000,000	805,000,000	1,495,000,000	842,000,000	899,000,000
Mexican Government bonds purchased	2,600,000,000
Net unrealized losses recorded in AOCI and excluded from gross unrecognized losses			$ 1,900,000,000	$ 2,300,000,000