Loans and Allowance for Credit Losses Textual (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014	Dec. 31, 2008
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Unearned income, net deferred loan fees and unamortized discount and premium	$ 4,000,000,000		$ 4,000,000,000		$ 4,500,000,000
Temporary advance arrangements	86,000,000,000		86,000,000,000		87,000,000,000
Commercial letters of credit, international trade	1,500,000,000		1,500,000,000		1,200,000,000
Allowance for credit losses, PCI loans	7,000,000	$ 8,000,000	7,000,000	$ 8,000,000	11,000,000
Nonaccrual loans	12,443,000,000		12,443,000,000		12,848,000,000
90 days or more past due and still accruing	15,161,000,000		15,161,000,000		17,810,000,000
High value properties, threshold ($1 million or more)	1,000,000		1,000,000
Impaired loans	24,921,000,000		24,921,000,000		25,408,000,000
Total unfunded loan commitments on troubled debt restructurings	373,000,000		373,000,000		341,000,000
Loans remodified	566,000,000	558,000,000	1,100,000,000	1,200,000
Financing receivable modifications, principal forgiven	20,000,000	44,000,000	46,000,000	92,000,000
Purchased Credit Impaired Loans (carrying value)	21,555,000,000		21,555,000,000		23,320,000,000
Total PCI loans (unpaid principal balance)	30,369,000,000		30,369,000,000		32,924,000,000	$ 98,200,000,000
Home Affordable Modification Program [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	152,000,000		152,000,000		149,000,000
Second Lien Modification Program [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	36,000,000		36,000,000		34,000,000
Proprietary Program [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	262,000,000		262,000,000		269,000,000
Purchased Credit-Impaired Loans [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
90 days or more past due and still accruing	3,400,000,000		3,400,000,000		3,700,000,000
Trial modifications [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	450,000,000		450,000,000		452,000,000
Trial modifications [Member] | Financing Receivable Accruing [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	163,000,000		163,000,000		167,000,000
Trial modifications [Member] | Financing Receivable Nonaccruing [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Impaired loans	287,000,000		287,000,000		285,000,000
In process of foreclosure [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Recorded investment amount in consumer mortgage loans collateralized by residential real estate property	12,400,000,000		$ 12,400,000,000		12,700,000,000
Consumer Loans Exempt Under Regulatory Rules [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Nonperforming status threshold			120 days
Commercial Real Estate Mortgage and Construction Loans [Member] | Criticized [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Loans, excluding Purchased Credit Impaired Loans	8,700,000,000		$ 8,700,000,000
Nonaccrual loans	1,400,000,000		1,400,000,000
FHA Insured/VA Guaranteed [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Financing receivable, certain purchases net of certain transfers to held for sale	(228,000,000)	$ (1,300,000,000)	900,000,000	$ 237,000,000
90 days or more past due and still accruing	14,359,000,000		14,359,000,000		16,827,000,000
FHA Insured/VA Guaranteed [Member] | Impaired Loans [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Government insured/guaranteed loans	1,900,000,000		1,900,000,000		2,100,000,000
FHA Insured/VA Guaranteed [Member] | Financing Receivable 90 Days Or More Past Due [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Government insured/guaranteed loans	13,900,000,000		13,900,000,000		16,200,000,000
FHA Insured/VA Guaranteed [Member] | In process of foreclosure [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Recorded investment amount in consumer mortgage loans collateralized by residential real estate property	6,500,000,000		6,500,000,000		6,600,000,000
Student Loans guaranteed under FFELP [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
90 days or more past due and still accruing	46,000,000		46,000,000		63,000,000
Total Commercial [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Allowance for credit losses, PCI loans	7,000,000		7,000,000		11,000,000
Nonaccrual loans	2,522,000,000		2,522,000,000		2,239,000,000
Impaired loans	3,902,000,000		$ 3,902,000,000		3,759,000,000
Nonperforming status threshold			90 days
Purchased Credit Impaired Loans (carrying value)	873,000,000		$ 873,000,000		1,507,000,000	18,700,000,000
Total Commercial [Member] | Loans held for sale [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Nonaccrual loans	0		0		1,000,000
Total Commercial [Member] | Purchased Credit-Impaired Loans [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
90 days or more past due and still accruing	64,000,000		64,000,000		83,000,000
Purchased Credit Impaired Loans (carrying value)	873,000,000		873,000,000		1,507,000,000
Total Commercial [Member] | Loans Excluding Certain Loans Acquired In Transfer With Evidence Of Credit Deterioration [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Loans, excluding Purchased Credit Impaired Loans	437,149,000,000		437,149,000,000		413,319,000,000
Nonaccrual loans	2,522,000,000		2,522,000,000		2,239,000,000
90 days or more past due and still accruing	27,000,000		27,000,000		47,000,000
Total Commercial [Member] | Criticized [Member] | Purchased Credit-Impaired Loans [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Purchased Credit Impaired Loans (carrying value)	376,000,000		376,000,000		585,000,000
Total Commercial [Member] | Criticized [Member] | Loans Excluding Certain Loans Acquired In Transfer With Evidence Of Credit Deterioration [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Loans, excluding Purchased Credit Impaired Loans	25,105,000,000		25,105,000,000		25,005,000,000
Total Consumer [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Allowance for credit losses, PCI loans	0		0		0
Nonaccrual loans	9,921,000,000		9,921,000,000		10,609,000,000
Loans, 90 days or more past due	5,900,000,000		5,900,000,000		6,700,000,000
90 days or more past due and still accruing	729,000,000		729,000,000		873,000,000
Impaired loans	21,019,000,000		$ 21,019,000,000		21,649,000,000
Nonperforming status threshold			60 days
Purchased Credit Impaired Loans (carrying value)	20,682,000,000		$ 20,682,000,000		21,813,000,000	$ 40,100,000,000
Total Consumer [Member] | Loans Excluding Certain Loans Acquired In Transfer With Evidence Of Credit Deterioration [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Loans, excluding Purchased Credit Impaired Loans	429,755,000,000		429,755,000,000		425,912,000,000
Government insured/guaranteed loans	23,889,000,000		23,889,000,000		26,268,000,000
180 or more DPD	4,348,000,000		4,348,000,000		4,737,000,000
FICO not required	6,536,000,000		6,536,000,000		5,854,000,000
Real estate 1-4 family first mortgage [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Nonaccrual loans	$ 8,045,000,000		$ 8,045,000,000		$ 8,583,000,000
180 or more DPD and still accruing, percentage of portfolio	1.60%		1.60%		1.70%
Impaired loans	$ 18,035,000,000		$ 18,035,000,000		$ 18,600,000,000
Purchased Credit Impaired Loans (carrying value)	20,601,000,000		20,601,000,000		21,712,000,000
Real estate 1-4 family first mortgage [Member] | Mortgages held for sale [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Nonaccrual loans	144,000,000		144,000,000		177,000,000
Real estate 1-4 family first mortgage [Member] | Purchased Credit-Impaired Loans [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
180 or more DPD	3,502,000,000		3,502,000,000		3,654,000,000
Purchased Credit Impaired Loans (carrying value)	20,601,000,000		20,601,000,000		21,712,000,000
Real estate 1-4 family first mortgage [Member] | Loans Excluding Certain Loans Acquired In Transfer With Evidence Of Credit Deterioration [Member]
Accounts Notes Loans And Financing Receivable (Textual) [Abstract]
Loans, excluding Purchased Credit Impaired Loans	247,267,000,000		247,267,000,000		243,674,000,000
Government insured/guaranteed loans	23,889,000,000		23,889,000,000		26,268,000,000
180 or more DPD	3,897,000,000		3,897,000,000		4,258,000,000
FICO not required	$ 0		$ 0		$ 0