Loans - Impaired Loans (Details 3) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Financing Receivable, Impaired [Line Items]
Retained loans	$ 712,898,000,000	$ 675,437,000,000	$ 718,997,000,000
Modified Loans Repurchased From U S Government Agencies Excluded From Troubled Debt Restructurings	4,700,000,000	4,300,000,000
Average Impaired Loans And Related Interest Income Abstract
Loans And Leases Receivable, Impaired, Trouble Debt Restructuring Not Yet Made Six Payments	837,000,000	640,000,000
Consumer Loan Excluding Credit Card
Financing Receivable, Impaired [Line Items]
Retained loans	304,770,000,000		308,427,000,000
Residential real estate, excluding PCI [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	160,788,000,000		163,660,000,000
Impaired loans	9,288,000,000		9,088,000,000
Allowance for loan losses related to impaired loans	530,000,000		591,000,000
Unpaid principal balance of impaired loans	12,847,000,000		12,444,000,000
Impaired Loans On Nonaccrual Status	1,893,000,000		1,990,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	9,187,000,000	6,087,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	100,000,000	67,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	11,000,000	6,000,000
Residential real estate, excluding PCI [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	8,498,000,000		8,320,000,000
Residential real estate, excluding PCI [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	790,000,000		768,000,000
Home Equity Senior Lien [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	21,202,000,000		21,765,000,000
Impaired loans	338,000,000		335,000,000
Allowance for loan losses related to impaired loans	110,000,000		80,000,000
Unpaid principal balance of impaired loans	444,000,000		433,000,000
Impaired Loans On Nonaccrual Status	68,000,000		77,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	336,000,000	242,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	3,000,000	3,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	1,000,000	0
Home Equity Senior Lien [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	322,000,000		319,000,000
Home Equity Senior Lien [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	16,000,000		16,000,000
Home Equity Junior Lien [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	54,005,000,000		56,035,000,000
Impaired loans	706,000,000		657,000,000
Allowance for loan losses related to impaired loans	207,000,000		141,000,000
Unpaid principal balance of impaired loans	1,085,000,000		994,000,000
Impaired Loans On Nonaccrual Status	209,000,000		159,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	686,000,000	361,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	6,000,000	4,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	1,000,000	0
Home Equity Junior Lien [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	627,000,000		622,000,000
Home Equity Junior Lien [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	79,000,000		35,000,000
Prime Mortgages, including option ARMs [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	76,292,000,000		76,196,000,000
Impaired loans	5,018,000,000		4,877,000,000
Allowance for loan losses related to impaired loans	4,000,000		4,000,000
Unpaid principal balance of impaired loans	6,446,000,000		6,190,000,000
Impaired Loans On Nonaccrual Status	888,000,000		922,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	4,949,000,000	2,616,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	49,000,000	26,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	5,000,000	3,000,000
Prime Mortgages, including option ARMs [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	4,487,000,000		4,332,000,000
Prime Mortgages, including option ARMs [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	531,000,000		545,000,000
Subprime Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	9,289,000,000		9,664,000,000
Impaired loans	3,226,000,000		3,219,000,000
Allowance for loan losses related to impaired loans	209,000,000		366,000,000
Unpaid principal balance of impaired loans	4,872,000,000		4,827,000,000
Impaired Loans On Nonaccrual Status	728,000,000		832,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	3,216,000,000	2,868,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	42,000,000	34,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	4,000,000	3,000,000
Subprime Mortgage [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	3,062,000,000		3,047,000,000
Subprime Mortgage [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	164,000,000		172,000,000
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	79,921,000,000		79,221,000,000
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	48,245,000,000		47,426,000,000
Consumer business banking
Financing Receivable, Impaired [Line Items]
Retained loans	17,822,000,000		17,652,000,000
Credit Card Loan Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	124,475,000,000		132,175,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	6,845,000,000	9,494,000,000
Impaired Financing Receivable, Interest Income, Accrual Method	89,000,000	130,000,000
Wholesale
Financing Receivable, Impaired [Line Items]
Retained loans	283,653,000,000		278,395,000,000
Impaired loans	2,058,000,000		2,549,000,000
Allowance for loan losses related to impaired loans	448,000,000		516,000,000
Unpaid principal balance of impaired loans	3,076,000,000		3,917,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	2,232,000,000	5,036,000,000
Wholesale | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	1,438,000,000		1,959,000,000
Wholesale | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	620,000,000		590,000,000
Wholesale | Commercial and industrial [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	97,089,000,000		94,215,000,000
Impaired loans	886,000,000		1,005,000,000
Allowance for loan losses related to impaired loans	239,000,000		276,000,000
Unpaid principal balance of impaired loans	1,537,000,000		1,705,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	918,000,000	1,553,000,000
Wholesale | Commercial and industrial [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	642,000,000		828,000,000
Wholesale | Commercial and industrial [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	244,000,000		177,000,000
Wholesale | Real estate[Member]
Financing Receivable, Impaired [Line Items]
Retained loans	56,747,000,000		54,684,000,000
Impaired loans	819,000,000		913,000,000
Allowance for loan losses related to impaired loans	97,000,000		148,000,000
Unpaid principal balance of impaired loans	997,000,000		1,124,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	875,000,000	2,730,000,000
Wholesale | Real estate[Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	594,000,000		621,000,000
Wholesale | Real estate[Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	225,000,000		292,000,000
Wholesale | Financial institutions [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	35,629,000,000		38,219,000,000
Impaired loans	23,000,000		39,000,000
Allowance for loan losses related to impaired loans	3,000,000		5,000,000
Unpaid principal balance of impaired loans	47,000,000		63,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	28,000,000	94,000,000
Wholesale | Financial institutions [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	10,000,000		21,000,000
Wholesale | Financial institutions [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	13,000,000		18,000,000
Wholesale | Government agencies [Member]
Financing Receivable, Impaired [Line Items]
Retained loans	7,814,000,000		7,819,000,000
Impaired loans	14,000,000		16,000,000
Allowance for loan losses related to impaired loans	8,000,000		10,000,000
Unpaid principal balance of impaired loans	15,000,000		17,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	16,000,000	22,000,000
Wholesale | Government agencies [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	14,000,000		16,000,000
Wholesale | Government agencies [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	0		0
Wholesale | Wholesale Other Member
Financing Receivable, Impaired [Line Items]
Retained loans	86,374,000,000		83,458,000,000
Impaired loans	316,000,000		576,000,000
Allowance for loan losses related to impaired loans	101,000,000		77,000,000
Unpaid principal balance of impaired loans	480,000,000		1,008,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	395,000,000	637,000,000
Wholesale | Wholesale Other Member | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	178,000,000		473,000,000
Wholesale | Wholesale Other Member | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	138,000,000		103,000,000
Consumer Excluding Credit Card
Financing Receivable, Impaired [Line Items]
Retained loans	304,770,000,000		308,427,000,000
Consumer Excluding Credit Card | Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans	771,000,000		804,000,000
Allowance for loan losses related to impaired loans	230,000,000		237,000,000
Unpaid principal balance of impaired loans	912,000,000		948,000,000
Financing Receivable, Recorded Investment, Nonaccrual Status	564,000,000		592,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	780,000,000	871,000,000
Consumer Excluding Credit Card | Other Consumer [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	771,000,000		801,000,000
Consumer Excluding Credit Card | Other Consumer [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	0		3,000,000
Consumer Excluding Credit Card | Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans	92,000,000		91,000,000
Allowance for loan losses related to impaired loans	14,000,000		12,000,000
Unpaid principal balance of impaired loans	128,000,000		126,000,000
Financing Receivable, Recorded Investment, Nonaccrual Status	42,000,000		41,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	92,000,000	99,000,000
Consumer Excluding Credit Card | Consumer Loans Auto Financing Receivable [Member] | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	92,000,000		88,000,000
Consumer Excluding Credit Card | Consumer Loans Auto Financing Receivable [Member] | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	0		3,000,000
Consumer Excluding Credit Card | Consumer business banking
Financing Receivable, Impaired [Line Items]
Impaired loans	679,000,000		713,000,000
Allowance for loan losses related to impaired loans	216,000,000		225,000,000
Unpaid principal balance of impaired loans	784,000,000		822,000,000
Financing Receivable, Recorded Investment, Nonaccrual Status	522,000,000		551,000,000
Average Impaired Loans And Related Interest Income Abstract
Impaired loans (average)	688,000,000	772,000,000
Consumer Excluding Credit Card | Consumer business banking | Impaired Financing Receivable with Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	679,000,000		713,000,000
Consumer Excluding Credit Card | Consumer business banking | Impaired Financing Receivable with No Related Allowance [Domain]
Financing Receivable, Impaired [Line Items]
Impaired loans	$ 0		$ 0