Loans - Impaired (Details) (USD $)									3 Months Ended				3 Months Ended				3 Months Ended							3 Months Ended							3 Months Ended							3 Months Ended							3 Months Ended						3 Months Ended							3 Months Ended									3 Months Ended		12 Months Ended										3 Months Ended							3 Months Ended							3 Months Ended													3 Months Ended					3 Months Ended					3 Months Ended					3 Months Ended
Loans - Impaired (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Consumer, excluding credit card	Dec. 31, 2012 Consumer, excluding credit card	Mar. 31, 2012 Consumer, excluding credit card	Mar. 31, 2013 Consumer, excluding credit card Consumer Loan Excluding Credit Card	Dec. 31, 2012 Consumer, excluding credit card Consumer Loan Excluding Credit Card	Mar. 31, 2013 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member]	Mar. 31, 2012 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member]	Dec. 31, 2012 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member]	Dec. 31, 2011 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member]	Mar. 31, 2013 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member] Days Past Due, 60 or More, with Notification of Bankruptcy Filing or Other Event [Member]	Mar. 31, 2013 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member] Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member] Regulatory Guidance Regarding Chapter 7 Loans [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Senior Lien	Mar. 31, 2012 Consumer, excluding credit card Home Equity - Senior Lien	Dec. 31, 2012 Consumer, excluding credit card Home Equity - Senior Lien	Dec. 31, 2011 Consumer, excluding credit card Home Equity - Senior Lien	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Senior Lien Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Home Equity - Senior Lien Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Senior Lien Regulatory Guidance Regarding Chapter 7 Loans [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Junior Lien	Mar. 31, 2012 Consumer, excluding credit card Home Equity - Junior Lien	Dec. 31, 2012 Consumer, excluding credit card Home Equity - Junior Lien	Dec. 31, 2011 Consumer, excluding credit card Home Equity - Junior Lien	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Junior Lien Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Home Equity - Junior Lien Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Home Equity - Junior Lien Regulatory Guidance Regarding Chapter 7 Loans [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Prime Mortgages, Including Option ARMs	Mar. 31, 2012 Consumer, excluding credit card Prime Mortgages, Including Option ARMs	Dec. 31, 2012 Consumer, excluding credit card Prime Mortgages, Including Option ARMs	Dec. 31, 2011 Consumer, excluding credit card Prime Mortgages, Including Option ARMs	Mar. 31, 2013 Consumer, excluding credit card Prime Mortgages, Including Option ARMs Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Prime Mortgages, Including Option ARMs Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Prime Mortgages, Including Option ARMs Regulatory Guidance Regarding Prime, including Option ARM, mortgages [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Subprime Mortgages	Mar. 31, 2012 Consumer, excluding credit card Subprime Mortgages	Dec. 31, 2012 Consumer, excluding credit card Subprime Mortgages	Dec. 31, 2011 Consumer, excluding credit card Subprime Mortgages	Mar. 31, 2013 Consumer, excluding credit card Subprime Mortgages Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Subprime Mortgages Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Subprime Mortgages Regulatory Guidance Regarding Chapter 7 Loans [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Other Consumer [Member]	Mar. 31, 2012 Consumer, excluding credit card Other Consumer [Member]	Dec. 31, 2012 Consumer, excluding credit card Other Consumer [Member]	Dec. 31, 2011 Consumer, excluding credit card Other Consumer [Member]	Mar. 31, 2013 Consumer, excluding credit card Other Consumer [Member] Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Other Consumer [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Auto Loans	Mar. 31, 2012 Consumer, excluding credit card Auto Loans	Dec. 31, 2012 Consumer, excluding credit card Auto Loans	Dec. 31, 2011 Consumer, excluding credit card Auto Loans	Mar. 31, 2013 Consumer, excluding credit card Auto Loans Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Auto Loans Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Auto Loans Regulatory Guidance Regarding Chapter 7 Loans [Member] Nonaccrual [Member]	Mar. 31, 2013 Consumer, excluding credit card Business Banking Loans	Mar. 31, 2012 Consumer, excluding credit card Business Banking Loans	Dec. 31, 2012 Consumer, excluding credit card Business Banking Loans	Dec. 31, 2011 Consumer, excluding credit card Business Banking Loans	Mar. 31, 2013 Consumer, excluding credit card Business Banking Loans Nonaccrual [Member]	Dec. 31, 2012 Consumer, excluding credit card Business Banking Loans Nonaccrual [Member]	Mar. 31, 2013 Credit card	Dec. 31, 2012 Credit card	Mar. 31, 2012 Credit card	Mar. 31, 2013 Credit card Credit Card Loan	Mar. 31, 2012 Credit card Credit Card Loan	Dec. 31, 2012 Credit card Credit Card Loan	Mar. 31, 2013 Credit card Credit Card Loan Completion of Short Term Modification [Member]	Dec. 31, 2012 Credit card Credit Card Loan Completion of Short Term Modification [Member]	Mar. 31, 2013 Credit card Credit Card Loan Noncompliance With Modified Terms [Member]	Dec. 31, 2012 Credit card Credit Card Loan Noncompliance With Modified Terms [Member]	Mar. 31, 2013 Credit card Credit Card Loan Nonaccrual [Member]	Dec. 31, 2012 Credit card Credit Card Loan Nonaccrual [Member]	Mar. 31, 2013 Wholesale	Dec. 31, 2012 Wholesale	Mar. 31, 2012 Wholesale	Mar. 31, 2013 Wholesale Wholesale Loan [Member]	Mar. 31, 2012 Wholesale Wholesale Loan [Member]	Dec. 31, 2012 Wholesale Wholesale Loan [Member]	Dec. 31, 2011 Wholesale Wholesale Loan [Member]	Mar. 31, 2013 Wholesale Wholesale Loan [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Wholesale Loan [Member] Nonaccrual [Member]	Mar. 31, 2012 Wholesale Wholesale Loan [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Commercial and Industrial [Member]	Mar. 31, 2012 Wholesale Commercial and Industrial [Member]	Dec. 31, 2012 Wholesale Commercial and Industrial [Member]	Dec. 31, 2011 Wholesale Commercial and Industrial [Member]	Mar. 31, 2013 Wholesale Commercial and Industrial [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Commercial and Industrial [Member] Nonaccrual [Member]	Mar. 31, 2012 Wholesale Commercial and Industrial [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Wholesale Real Estate [Member]	Mar. 31, 2012 Wholesale Wholesale Real Estate [Member]	Dec. 31, 2012 Wholesale Wholesale Real Estate [Member]	Dec. 31, 2011 Wholesale Wholesale Real Estate [Member]	Mar. 31, 2013 Wholesale Wholesale Real Estate [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Wholesale Real Estate [Member] Nonaccrual [Member]	Mar. 31, 2012 Wholesale Wholesale Real Estate [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member]	Dec. 31, 2012 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member]	Mar. 31, 2012 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member]	Dec. 31, 2011 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member]	Mar. 31, 2013 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member] Nonaccrual [Member]	Mar. 31, 2012 Wholesale Financial Institutions, Government Agencies and Other Wholesale [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Financial Institutions [Member]	Mar. 31, 2012 Wholesale Financial Institutions [Member]	Dec. 31, 2012 Wholesale Financial Institutions [Member]	Mar. 31, 2013 Wholesale Financial Institutions [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Financial Institutions [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Government Agencies [Member]	Mar. 31, 2012 Wholesale Government Agencies [Member]	Dec. 31, 2012 Wholesale Government Agencies [Member]	Mar. 31, 2013 Wholesale Government Agencies [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Government Agencies [Member] Nonaccrual [Member]	Mar. 31, 2013 Wholesale Wholesale Other [Member]	Mar. 31, 2012 Wholesale Wholesale Other [Member]	Dec. 31, 2012 Wholesale Wholesale Other [Member]	Mar. 31, 2013 Wholesale Wholesale Other [Member] Nonaccrual [Member]	Dec. 31, 2012 Wholesale Wholesale Other [Member] Nonaccrual [Member]	Mar. 31, 2013 Minimum Consumer, excluding credit card loan_payment	Mar. 31, 2013 Minimum Consumer, excluding credit card Residential Real Estate, Excluding Purchased Credit-Impaired [Member] Regulatory Guidance Regarding Chapter 7 Loans [Member]
Financing Receivable, Impaired [Line Items]
Number of Payments Under Modified Terms to Recognize Interest on Cash Basis																																																																																																																									6
Rate of Default for Modified Loans, Estimated Weighted Average																								17.00%																																											36.49%		38.23%																																																					10.00%
Impaired Financing Receivable, Recorded Investment [Abstract]
Impaired Financing Receivable, with Related Allowance, Recorded Investment									$ 10,468,000,000		$ 10,100,000,000						$ 570,000,000		$ 542,000,000					$ 688,000,000		$ 677,000,000					$ 6,081,000,000		$ 5,810,000,000					$ 3,129,000,000		$ 3,071,000,000					$ 616,000,000		$ 621,000,000				$ 74,000,000		$ 78,000,000					$ 542,000,000		$ 543,000,000																			$ 1,021,000,000		$ 1,091,000,000					$ 407,000,000		$ 588,000,000					$ 431,000,000		$ 375,000,000											$ 5,000,000		$ 6,000,000			$ 0		$ 0			$ 178,000,000		$ 122,000,000
Impaired Financing Receivable, with No Related Allowance, Recorded Investment									3,039,000,000		3,145,000,000						585,000,000		550,000,000					598,000,000		546,000,000					1,142,000,000		1,308,000,000					714,000,000		741,000,000					66,000,000		72,000,000				66,000,000		72,000,000					0		0																			281,000,000		384,000,000					99,000,000		173,000,000					134,000,000		133,000,000											2,000,000		2,000,000			0		0			46,000,000		76,000,000
Impaired Financing Receivable, Recorded Investment									13,507,000,000		13,245,000,000			4,735,000,000	4,402,000,000		1,155,000,000		1,092,000,000		659,000,000	607,000,000		1,286,000,000		1,223,000,000		670,000,000	599,000,000		7,223,000,000		7,118,000,000		2,045,000,000	1,888,000,000		3,843,000,000		3,812,000,000		1,361,000,000	1,308,000,000		682,000,000		693,000,000		490,000,000	503,000,000	140,000,000		150,000,000		102,000,000	109,000,000		542,000,000		543,000,000		388,000,000	394,000,000				4,287,000,000		4,762,000,000										1,302,000,000		1,475,000,000					506,000,000		761,000,000					565,000,000		508,000,000											7,000,000		8,000,000			0		0			224,000,000		198,000,000
Impaired Financing Receivable, Related Allowance									644,000,000		591,000,000						129,000,000		159,000,000					198,000,000		188,000,000					192,000,000		70,000,000					125,000,000		174,000,000					127,000,000		138,000,000				11,000,000		12,000,000					116,000,000		126,000,000							1,434,000,000		1,681,000,000										228,000,000		319,000,000					108,000,000		205,000,000					79,000,000		82,000,000											2,000,000		2,000,000			0		0			39,000,000		30,000,000
Loans Receivable Held for Investment, Net of Deferred Income	722,529,000,000	726,835,000,000	712,898,000,000	290,082,000,000	292,620,000,000	304,770,000,000	290,082,000,000	292,620,000,000	150,427,000,000		151,896,000,000			8,375,000,000	8,460,000,000		18,743,000,000		19,385,000,000		943,000,000	931,000,000		46,055,000,000		48,000,000,000		2,161,000,000	2,277,000,000		77,626,000,000		76,256,000,000		3,479,000,000	3,445,000,000		8,003,000,000		8,255,000,000		1,792,000,000	1,807,000,000		81,218,000,000		80,987,000,000		673,000,000	714,000,000	50,552,000,000		49,913,000,000		135,000,000	163,000,000		18,739,000,000		18,883,000,000		458,000,000	481,000,000	121,865,000,000	127,993,000,000	124,475,000,000	121,865,000,000		127,993,000,000					1,000,000	1,000,000	310,582,000,000	306,222,000,000	283,653,000,000	310,582,000,000		306,222,000,000		1,247,000,000	1,434,000,000		111,584,000,000		109,865,000,000		453,000,000	708,000,000		61,380,000,000		60,740,000,000		564,000,000	520,000,000								43,794,000,000		36,227,000,000	7,000,000	8,000,000	8,997,000,000		9,544,000,000	0	0	84,827,000,000		89,846,000,000	223,000,000	198,000,000
Financing Receivable, Modifications, Recorded Investment									13,507,000,000	9,288,000,000	13,245,000,000	9,088,000,000				1,700,000,000	1,155,000,000	338,000,000	1,092,000,000	335,000,000			482,000,000	1,286,000,000	706,000,000	1,223,000,000	657,000,000			501,000,000	7,223,000,000	5,018,000,000	7,118,000,000	4,877,000,000			441,000,000	3,843,000,000	3,226,000,000	3,812,000,000	3,219,000,000			236,000,000	481,000,000	469,000,000	502,000,000	503,000,000	289,000,000	312,000,000	140,000,000	91,000,000	150,000,000	88,000,000	102,000,000	109,000,000	66,000,000	341,000,000	378,000,000	352,000,000	415,000,000	187,000,000	203,000,000				3,798,000,000		4,189,000,000										421,000,000	664,000,000	696,000,000	750,000,000	357,000,000		525,000,000	254,000,000	419,000,000	575,000,000	531,000,000	200,000,000		314,000,000	124,000,000	148,000,000	99,000,000	176,000,000	114,000,000		116,000,000	43,000,000	22,000,000	97,000,000	43,000,000	43,000,000	95,000,000
Modified Loans Repurchased From U S Government Agencies Excluded From Troubled Debt Restructurings				7,200,000,000	7,500,000,000
Loans and Leases Receivable, Impaired, Troubled Debt Restructurings Not Having Yet Made Six Payments									3,200,000,000		2,900,000,000
Period Past Due, Credit Analysis Factors, Charge off Criteria													90 days											180 days
Loans and Leases Receivable, Impaired, Reverted to Original Payment Terms Amount																																																																			489,000,000		573,000,000	206,000,000	232,000,000	283,000,000	341,000,000
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Impaired Financing Receivable, Unpaid Principal Balance									19,085,000,000		18,555,000,000						1,517,000,000		1,408,000,000					2,519,000,000		2,352,000,000					9,275,000,000		9,095,000,000					5,774,000,000		5,700,000,000					860,000,000		883,000,000				247,000,000		259,000,000					613,000,000		624,000,000																			1,722,000,000		1,923,000,000					614,000,000		957,000,000					665,000,000		626,000,000											22,000,000		22,000,000			0		0			421,000,000		318,000,000
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Impaired Financing Receivable, Average Recorded Investment									13,425,000,000	9,187,000,000							1,139,000,000	336,000,000						1,272,000,000	686,000,000						7,187,000,000	4,949,000,000						3,827,000,000	3,216,000,000						687,000,000	780,000,000					144,000,000	92,000,000						543,000,000	688,000,000								4,521,000,000	6,845,000,000											1,369,000,000	2,232,000,000						606,000,000	918,000,000						532,000,000	875,000,000												8,000,000	28,000,000				0	16,000,000				223,000,000	395,000,000
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Impaired Financing Receivable, Interest Income, Accrual Method									154,000,000	100,000,000							15,000,000	3,000,000						20,000,000	6,000,000						69,000,000	49,000,000						50,000,000	42,000,000																												58,000,000	89,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method									$ 52,000,000	$ 11,000,000							$ 10,000,000	$ 1,000,000						$ 13,000,000	$ 1,000,000						$ 14,000,000	$ 5,000,000						$ 15,000,000	$ 4,000,000