INVESTMENTS (Details) (USD $)	3 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Investments summary
Securities available-for-sale, at fair value	$ 271,261,000,000		$ 265,204,000,000
Debt securities held-to-maturity	10,943,000,000		11,483,000,000
Non-marketable equity securities carried at fair value	5,228,000,000		8,836,000,000
Non-marketable equity securities carried at cost	8,042,000,000		7,890,000,000
Total investments	295,474,000,000		293,413,000,000
Decrease in non-marketable equity securities carried at fair value	1,500,000,000	1,300,000,000
Securities available-for-sale
Fair value	271,261,000,000		265,204,000,000
Mortgage-backed securities
Investments summary
Securities available-for-sale, at fair value	52,244,000,000		51,025,000,000
Debt securities held-to-maturity	5,220,000,000		7,430,000,000
Securities available-for-sale
Amortized cost	50,362,000,000		49,649,000,000
Gross unrealized gains	1,948,000,000		1,464,000,000
Gross unrealized losses	66,000,000		88,000,000
Fair value	52,244,000,000		51,025,000,000
U.S. government-sponsored agency guaranteed
Investments summary
Securities available-for-sale, at fair value	44,217,000,000		45,781,000,000
Securities available-for-sale
Amortized cost	42,511,000,000		44,394,000,000
Gross unrealized gains	1,768,000,000		1,438,000,000
Gross unrealized losses	62,000,000		51,000,000
Fair value	44,217,000,000		45,781,000,000
Prime
Investments summary
Securities available-for-sale, at fair value	126,000,000		113,000,000
Debt securities held-to-maturity	243,000,000		287,000,000
Securities available-for-sale
Amortized cost	122,000,000		118,000,000
Gross unrealized gains	4,000,000		1,000,000
Gross unrealized losses			6,000,000
Fair value	126,000,000		113,000,000
Alt-A
Investments summary
Securities available-for-sale, at fair value	149,000,000		1,000,000
Debt securities held-to-maturity	2,236,000,000		3,328,000,000
Securities available-for-sale
Amortized cost	149,000,000		1,000,000
Fair value	149,000,000		1,000,000
Subprime
Investments summary
Debt securities held-to-maturity	203,000,000		336,000,000
Non-U.S. residential
Investments summary
Securities available-for-sale, at fair value	7,278,000,000		4,658,000,000
Debt securities held-to-maturity	2,231,000,000		2,967,000,000
Securities available-for-sale
Amortized cost	7,122,000,000		4,671,000,000
Gross unrealized gains	156,000,000		9,000,000
Gross unrealized losses			22,000,000
Fair value	7,278,000,000		4,658,000,000
Commercial
Investments summary
Securities available-for-sale, at fair value	474,000,000		472,000,000
Debt securities held-to-maturity	307,000,000		512,000,000
Securities available-for-sale
Amortized cost	458,000,000		465,000,000
Gross unrealized gains	20,000,000		16,000,000
Gross unrealized losses	4,000,000		9,000,000
Fair value	474,000,000		472,000,000
U.S. Treasury and federal agency securities
Investments summary
Securities available-for-sale, at fair value	84,408,000,000		85,138,000,000
Securities available-for-sale
Amortized cost	82,545,000,000		83,100,000,000
Gross unrealized gains	1,881,000,000		2,040,000,000
Gross unrealized losses	18,000,000		2,000,000
Fair value	84,408,000,000		85,138,000,000
U.S. Treasury
Investments summary
Securities available-for-sale, at fair value	57,422,000,000		50,229,000,000
Securities available-for-sale
Amortized cost	56,015,000,000		48,790,000,000
Gross unrealized gains	1,425,000,000		1,439,000,000
Gross unrealized losses	18,000,000
Fair value	57,422,000,000		50,229,000,000
Agency obligations
Investments summary
Securities available-for-sale, at fair value	26,986,000,000		34,909,000,000
Securities available-for-sale
Amortized cost	26,530,000,000		34,310,000,000
Gross unrealized gains	456,000,000		601,000,000
Gross unrealized losses			2,000,000
Fair value	26,986,000,000		34,909,000,000
State and municipal securities
Investments summary
Securities available-for-sale, at fair value	18,103,000,000		14,399,000,000
Debt securities held-to-maturity	1,223,000,000		1,327,000,000
Securities available-for-sale
Amortized cost	19,775,000,000		16,819,000,000
Gross unrealized gains	134,000,000		134,000,000
Gross unrealized losses	1,806,000,000		2,554,000,000
Fair value	18,103,000,000		14,399,000,000
Foreign government
Investments summary
Securities available-for-sale, at fair value	91,064,000,000		84,514,000,000
Debt securities held-to-maturity	2,849,000,000
Securities available-for-sale
Amortized cost	90,358,000,000		84,360,000,000
Gross unrealized gains	887,000,000		558,000,000
Gross unrealized losses	181,000,000		404,000,000
Fair value	91,064,000,000		84,514,000,000
Corporate
Investments summary
Securities available-for-sale, at fair value	9,767,000,000		10,257,000,000
Debt securities held-to-maturity	818,000,000		1,749,000,000
Securities available-for-sale
Amortized cost	9,401,000,000		10,005,000,000
Gross unrealized gains	397,000,000		305,000,000
Gross unrealized losses	31,000,000		53,000,000
Fair value	9,767,000,000		10,257,000,000
Asset-backed securities
Investments summary
Securities available-for-sale, at fair value	12,011,000,000		11,003,000,000
Debt securities held-to-maturity	833,000,000		977,000,000
Securities available-for-sale
Amortized cost	12,090,000,000		11,053,000,000
Gross unrealized gains	76,000,000		31,000,000
Gross unrealized losses	155,000,000		81,000,000
Fair value	12,011,000,000		11,003,000,000
Other debt securities
Investments summary
Securities available-for-sale, at fair value	54,000,000		683,000,000
Securities available-for-sale
Amortized cost	51,000,000		670,000,000
Gross unrealized gains	3,000,000		13,000,000
Fair value	54,000,000		683,000,000
Total debt securities AFS
Investments summary
Securities available-for-sale, at fair value	267,651,000,000		257,019,000,000
Securities available-for-sale
Amortized cost	264,582,000,000		255,656,000,000
Gross unrealized gains	5,326,000,000		4,545,000,000
Gross unrealized losses	2,257,000,000		3,182,000,000
Fair value	267,651,000,000		257,019,000,000
Marketable equity securities AFS
Investments summary
Securities available-for-sale, at fair value	3,610,000,000		8,185,000,000
Securities available-for-sale
Amortized cost	3,736,000,000		6,722,000,000
Gross unrealized gains	37,000,000		1,658,000,000
Gross unrealized losses	163,000,000		195,000,000
Fair value	3,610,000,000		8,185,000,000
Total securities AFS
Investments summary
Securities available-for-sale, at fair value	271,261,000,000		265,204,000,000
Securities available-for-sale
Amortized cost	268,318,000,000		262,378,000,000
Gross unrealized gains	5,363,000,000		6,203,000,000
Gross unrealized losses	2,420,000,000		3,377,000,000
Fair value	$ 271,261,000,000		$ 265,204,000,000