Fair Value Measurements (Details) (USD $)	12 Months Ended
	Dec. 31, 2010		Sep. 30, 2011		Jun. 30, 2011	Sep. 30, 2010	Jun. 30, 2010	Dec. 31, 2009
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	$ 78,599,000,000		$ 92,441,000,000
Derivative assets	73,000,000,000		79,044,000,000
Mortgage servicing rights	14,900,000,000		7,880,000,000		12,372,000,000	12,251,000,000	14,745,000,000	19,465,000,000
Loans held-for-sale	25,942,000,000		11,183,000,000
Other assets	70,531,000,000		38,378,000,000
Liabilities
Federal funds purchased and securities loaned or sold under agreements to repurchase	37,424,000,000		36,943,000,000
Long-term debt	50,984,000,000		48,235,000,000
Gross transfers between Level One and Level Two	1,300,000,000
Short-term Debt [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Liabilities
Commercial paper and other short-term borrowings	6,472,000,000		5,527,000,000	[1]
Level 3 [Member] | Asset-backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Commercial paper and other short-term borrowings	706,000,000		667,000,000
Level 3 [Member] | U.S. government and agency securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	0	[2]	0
Liabilities
Total trading account liabilities	0		0
U.S. government and agency securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	60,811,000,000	[2]	51,725,000,000
Liabilities
Total trading account liabilities	29,340,000,000		21,373,000,000
U.S. government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total trading account assets	28,237,000,000	[2]	30,354,000,000	[1]
Liabilities
Total trading account liabilities	23,357,000,000		18,867,000,000	[1]
U.S. government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total trading account assets	32,574,000,000	[2]	21,371,000,000	[1]
Liabilities
Total trading account liabilities	5,983,000,000		2,506,000,000	[1]
U.S. government and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total trading account assets	0	[2],[3]	0	[3]
Liabilities
Total trading account liabilities	0	[3]	0	[3]
Level 3 [Member] | Corporate securities and other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	7,751,000,000		7,492,000,000
Level 3 [Member] | Corporate securities, trading loans and other [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Total trading account liabilities	7,000,000		70,000,000
Corporate securities, trading loans and other [Member] | Fair Value, Measurements, Recurring [Member]
Liabilities
Total trading account liabilities	11,350,000,000		10,272,000,000
Corporate securities, trading loans and other [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Liabilities
Total trading account liabilities	224,000,000		675,000,000	[1]
Corporate securities, trading loans and other [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Liabilities
Total trading account liabilities	11,119,000,000		9,527,000,000	[1]
Corporate securities, trading loans and other [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Liabilities
Total trading account liabilities	0	[3]	0	[3]
Corporate securities and other [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	49,352,000,000		45,482,000,000
Corporate securities and other [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total trading account assets	732,000,000		1,345,000,000	[1]
Corporate securities and other [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total trading account assets	40,869,000,000		36,645,000,000	[1]
Corporate securities and other [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total trading account assets	0	[3]	0	[3]
Level 3 [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	623,000,000		597,000,000
Liabilities
Total trading account liabilities	0		0
Equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	32,129,000,000		23,639,000,000
Liabilities
Total trading account liabilities	15,482,000,000		18,614,000,000
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total trading account assets	23,249,000,000		16,227,000,000	[1]
Liabilities
Total trading account liabilities	14,568,000,000		16,366,000,000	[1]
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total trading account assets	8,257,000,000		6,815,000,000	[1]
Liabilities
Total trading account liabilities	914,000,000		2,248,000,000	[1]
Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total trading account assets	0	[3]	0	[3]
Liabilities
Total trading account liabilities	0	[3]	0	[3]
Level 3 [Member] | Non-U.S. sovereign debt [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	243,000,000		375,000,000
Liabilities
Total trading account liabilities	0		0
Non-U.S. sovereign debt [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	33,523,000,000		43,112,000,000
Liabilities
Total trading account liabilities	15,813,000,000		17,767,000,000
Non-U.S. sovereign debt [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total trading account assets	24,934,000,000		33,531,000,000	[1]
Liabilities
Total trading account liabilities	14,748,000,000		17,126,000,000	[1]
Non-U.S. sovereign debt [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total trading account assets	8,346,000,000		9,206,000,000	[1]
Liabilities
Total trading account liabilities	1,065,000,000		641,000,000	[1]
Non-U.S. sovereign debt [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total trading account assets	0	[3]	0	[3]
Liabilities
Total trading account liabilities	0	[3]	0	[3]
Level 3 [Member] | Mortgage trading loans and ABS [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	6,908,000,000		3,771,000,000
Mortgage trading loans and ABS [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total trading account assets	18,856,000,000		12,440,000,000
Mortgage trading loans and ABS [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total trading account assets	0		0	[1]
Mortgage trading loans and ABS [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total trading account assets	11,948,000,000		8,669,000,000	[1]
Mortgage trading loans and ABS [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total trading account assets	0	[3]	0	[3]
Level 3 [Member] | U.S. Treasury securities and agency securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	0		0
U.S. Treasury securities and agency securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	49,105,000,000		60,031,000,000
U.S. Treasury securities and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	46,003,000,000		56,600,000,000	[1]
U.S. Treasury securities and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	3,102,000,000		3,431,000,000	[1]
U.S. Treasury securities and agency securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	4,000,000		13,000,000
Agency [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	191,217,000,000		160,079,000,000
Agency [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Agency [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	191,213,000,000		160,066,000,000	[1]
Agency [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Agency-collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities			55,000,000
Agency-collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	37,017,000,000		53,238,000,000
Agency-collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Agency-collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	37,017,000,000		53,183,000,000	[1]
Agency-collateralized mortgage obligations [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Non-agency residential [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities			1,080,000,000
Non-agency residential [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	23,117,000,000		17,594,000,000
Non-agency residential [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Non-agency residential [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	21,649,000,000		16,514,000,000	[1]
Non-agency residential [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Non-agency commercial [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities			35,000,000
Non-agency commercial [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	6,852,000,000		6,599,000,000
Non-agency commercial [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Non-agency commercial [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	6,833,000,000		6,564,000,000	[1]
Non-agency commercial [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Non-U.S. Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	3,000,000		0
Non-U.S. Securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	4,139,000,000		4,963,000,000
Non-U.S. Securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	1,440,000,000		1,938,000,000	[1]
Non-U.S. Securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	2,696,000,000		3,025,000,000	[1]
Non-U.S. Securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Corporate/Agency bonds [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	137,000,000		364,000,000
Corporate/Agency bonds [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	5,291,000,000		4,116,000,000
Corporate/Agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Corporate/Agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	5,154,000,000		3,752,000,000	[1]
Corporate/Agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Other taxable securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	13,018,000,000		9,342,000,000
Other taxable securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	15,392,000,000		12,468,000,000
Other taxable securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	20,000,000		20,000,000	[1]
Other taxable securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	2,354,000,000		3,106,000,000	[1]
Other taxable securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Tax-exempt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	1,224,000,000		2,873,000,000
Tax-exempt securities [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Total available-for-sale debt securities	5,497,000,000		5,179,000,000
Tax-exempt securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Total available-for-sale debt securities	0		0	[1]
Tax-exempt securities [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Total available-for-sale debt securities	4,273,000,000		2,306,000,000	[1]
Tax-exempt securities [Member] | Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Total available-for-sale debt securities	0	[3]	0	[3]
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	0		0
Total trading account assets	15,525,000,000		12,235,000,000
Derivative assets	18,773,000,000	[4]	16,047,000,000	[4]		20,400,000,000
Total available-for-sale debt securities	15,873,000,000		13,762,000,000
Loans And Leases Fair Value Disclosure	3,321,000,000		5,300,000,000
Mortgage servicing rights	14,900,000,000		7,880,000,000
Loans held-for-sale			3,630,000,000
Other assets			5,750,000,000
Total assets	79,388,000,000		64,604,000,000
Liabilities
Interest-bearing deposits in U.S. offices	0		0
Federal funds purchased and securities loaned or sold under agreements to repurchase	0		0
Total trading account liabilities	7,000,000		70,000,000
Derivative liabilities	11,028,000,000	[4]	9,800,000,000			10,900,000,000
Commercial paper and other short-term borrowings	706,000,000		667,000,000
Accrued expenses and other liabilities	828,000,000		13,000,000
Long-term debt	2,986,000,000		2,657,000,000
Total liabilities	15,555,000,000		13,162,000,000
Fair Value, Measurements, Recurring [Member]
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	78,599,000,000		92,441,000,000
Total trading account assets	194,671,000,000		176,398,000,000
Derivative assets	73,000,000,000	[4]	79,044,000,000	[4]
Total available-for-sale debt securities	337,627,000,000		324,267,000,000
Loans And Leases Fair Value Disclosure	3,321,000,000		11,224,000,000
Mortgage servicing rights	14,900,000,000		7,880,000,000
Loans held-for-sale	25,942,000,000		11,183,000,000
Other assets	70,531,000,000		38,378,000,000
Total assets	798,591,000,000		740,815,000,000
Liabilities
Interest-bearing deposits in U.S. offices	2,732,000,000		3,268,000,000
Federal funds purchased and securities loaned or sold under agreements to repurchase	37,424,000,000		36,943,000,000
Total trading account liabilities	71,985,000,000		68,026,000,000
Derivative liabilities	55,914,000,000	[4]	59,304,000,000	[4]
Commercial paper and other short-term borrowings	7,178,000,000		6,194,000,000
Accrued expenses and other liabilities	33,229,000,000		15,518,000,000
Long-term debt	50,984,000,000		48,235,000,000
Total liabilities	259,446,000,000		237,488,000,000
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	0		0	[1]
Total trading account assets	77,152,000,000		81,457,000,000	[1]
Derivative assets	2,627,000,000	[4]	4,978,000,000	[1],[4]
Total available-for-sale debt securities	47,463,000,000		58,558,000,000	[1]
Loans And Leases Fair Value Disclosure	0	[1]	0	[1]
Mortgage servicing rights	0		0	[1]
Loans held-for-sale	0		0	[1]
Other assets	32,624,000,000		22,804,000,000	[1]
Total assets	159,866,000,000		167,797,000,000	[1]
Liabilities
Interest-bearing deposits in U.S. offices	0		0	[1]
Federal funds purchased and securities loaned or sold under agreements to repurchase	0		0	[1]
Total trading account liabilities	52,897,000,000		53,034,000,000	[1]
Derivative liabilities	1,799,000,000	[4]	4,951,000,000	[1],[4]
Commercial paper and other short-term borrowings	0		0	[1]
Accrued expenses and other liabilities	31,470,000,000		13,485,000,000	[1]
Long-term debt	0		0	[1]
Total liabilities	86,166,000,000		71,470,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	78,599,000,000		92,441,000,000	[1]
Total trading account assets	101,994,000,000		82,706,000,000	[1]
Derivative assets	1,516,244,000,000	[4]	2,151,021,000,000	[1],[4]
Total available-for-sale debt securities	274,291,000,000		251,947,000,000	[1]
Loans And Leases Fair Value Disclosure	0	[1]	5,924,000,000	[1]
Mortgage servicing rights	0		0	[1]
Loans held-for-sale	21,802,000,000		7,553,000,000	[1]
Other assets	31,051,000,000		9,824,000,000	[1]
Total assets	2,023,981,000,000		2,601,416,000,000	[1]
Liabilities
Interest-bearing deposits in U.S. offices	2,732,000,000		3,268,000,000	[1]
Federal funds purchased and securities loaned or sold under agreements to repurchase	37,424,000,000		36,943,000,000	[1]
Total trading account liabilities	19,081,000,000		14,922,000,000	[1]
Derivative liabilities	1,492,963,000,000	[4]	2,129,395,000,000	[1],[4]
Accrued expenses and other liabilities	931,000,000		2,020,000,000	[1]
Long-term debt	47,998,000,000		45,578,000,000	[1]
Total liabilities	1,607,601,000,000		2,237,653,000,000	[1]
Fair Value, Measurements, Recurring [Member] | Netting Adjustments [Member]
Assets
Federal funds sold and securities borrowed or purchased under agreements to resell	0	[3]	0	[3]
Total trading account assets	0	[3]	0	[3]
Derivative assets	(1,464,644,000,000)	[3],[4]	(2,093,002,000,000)	[3],[4]
Total available-for-sale debt securities	0	[3]	0	[3]
Loans And Leases Fair Value Disclosure	0	[3]	0	[3]
Mortgage servicing rights	0	[3]	0	[3]
Loans held-for-sale	0	[3]	0	[3]
Other assets	0	[3]	0	[3]
Total assets	(1,464,644,000,000)	[3]	(2,093,002,000,000)	[3]
Liabilities
Interest-bearing deposits in U.S. offices	0	[3]	0	[3]
Federal funds purchased and securities loaned or sold under agreements to repurchase	0	[3]	0	[3]
Total trading account liabilities	0	[3]	0	[3]
Derivative liabilities	(1,449,876,000,000)	[3],[4]	(2,084,797,000,000)	[3],[4]
Commercial paper and other short-term borrowings	0	[3]	0	[3]
Accrued expenses and other liabilities	0	[3]	0	[3]
Long-term debt	0	[3]	0	[3]
Total liabilities	$ (1,449,876,000,000)	[3]	$ (2,084,797,000,000)	[3]

[1] Gross transfers between Level 1 and Level 2 were not significant during the nine months ended September 30, 2011.

[2] Certain prior period amounts have been reclassified to conform to current period presentation.

[3] Amounts represent the impact of legally enforceable master netting agreements and also cash collateral held or placed with the same counterparties.

[4] For further disaggregation of derivative assets and liabilities, see Note 4 – Derivatives.