Loans - Consumer, Excluding Credit Card Loans, Other Consumer Loans (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	756,971,000,000	$ 747,508,000,000	$ 721,160,000,000
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	304,917,000,000	294,979,000,000	287,930,000,000
Consumer, excluding credit card | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	55,455,000,000	54,536,000,000
% of 30 days past due to total retained loans	0.90%	1.23%
Consumer, excluding credit card | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	20,375,000,000	20,058,000,000
% of 30 days past due to total retained loans	1.65%	1.73%
Consumer, excluding credit card | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	10,740,000,000	10,970,000,000
% of 30 days past due to total retained loans	1.64%	2.15%
Consumer, excluding credit card | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	86,570,000,000	85,564,000,000
% of 30 days past due to total retained loans	1.17%	1.47%
Consumer, excluding credit card | California | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	6,469,000,000	6,294,000,000
Consumer, excluding credit card | California | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,059,000,000	3,008,000,000
Consumer, excluding credit card | California | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,128,000,000	1,143,000,000
Consumer, excluding credit card | California | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	10,656,000,000	10,445,000,000
Consumer, excluding credit card | New York | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,703,000,000	3,662,000,000
Consumer, excluding credit card | New York | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,171,000,000	3,187,000,000
Consumer, excluding credit card | New York | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,235,000,000	1,259,000,000
Consumer, excluding credit card | New York | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	8,109,000,000	8,108,000,000
Consumer, excluding credit card | Illinois | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,365,000,000	3,175,000,000
Consumer, excluding credit card | Illinois | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,387,000,000	1,373,000,000
Consumer, excluding credit card | Illinois | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	716,000,000	729,000,000
Consumer, excluding credit card | Illinois | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	5,468,000,000	5,277,000,000
Consumer, excluding credit card | Florida | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	2,428,000,000	2,301,000,000
Consumer, excluding credit card | Florida | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	861,000,000	827,000,000
Consumer, excluding credit card | Florida | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	521,000,000	521,000,000
Consumer, excluding credit card | Florida | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,810,000,000	3,649,000,000
Consumer, excluding credit card | Texas | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	5,804,000,000	5,608,000,000
Consumer, excluding credit card | Texas | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	2,610,000,000	2,626,000,000
Consumer, excluding credit card | Texas | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	849,000,000	868,000,000
Consumer, excluding credit card | Texas | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	9,263,000,000	9,102,000,000
Consumer, excluding credit card | New Jersey | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,947,000,000	1,945,000,000
Consumer, excluding credit card | New Jersey | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	530,000,000	451,000,000
Consumer, excluding credit card | New Jersey | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	391,000,000	378,000,000
Consumer, excluding credit card | New Jersey | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	2,868,000,000	2,774,000,000
Consumer, excluding credit card | Arizona | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,879,000,000	2,003,000,000
Consumer, excluding credit card | Arizona | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,148,000,000	1,083,000,000
Consumer, excluding credit card | Arizona | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	234,000,000	239,000,000
Consumer, excluding credit card | Arizona | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,261,000,000	3,325,000,000
Consumer, excluding credit card | Washington | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,042,000,000	1,019,000,000
Consumer, excluding credit card | Washington | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	274,000,000	258,000,000
Consumer, excluding credit card | Washington | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	224,000,000	235,000,000
Consumer, excluding credit card | Washington | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,540,000,000	1,512,000,000
Consumer, excluding credit card | Michigan | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,634,000,000	1,633,000,000
Consumer, excluding credit card | Michigan | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,344,000,000	1,375,000,000
Consumer, excluding credit card | Michigan | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	453,000,000	466,000,000
Consumer, excluding credit card | Michigan | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,431,000,000	3,474,000,000
Consumer, excluding credit card | Ohio | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	2,261,000,000	2,157,000,000
Consumer, excluding credit card | Ohio | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,455,000,000	1,354,000,000
Consumer, excluding credit card | Ohio | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	607,000,000	629,000,000
Consumer, excluding credit card | Ohio | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	4,323,000,000	4,140,000,000
Consumer, excluding credit card | All other | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	24,923,000,000	24,739,000,000
Consumer, excluding credit card | All other | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	4,536,000,000	4,516,000,000
Consumer, excluding credit card | All other | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	4,382,000,000	4,503,000,000
Consumer, excluding credit card | All other | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	33,841,000,000	33,758,000,000
Consumer, excluding credit card | In Process of Active or Suspended Foreclosure
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,400,000,000	1,500,000,000
Consumer, excluding credit card | Current and less than 30 days past due and still accruing | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	54,956,000,000	53,866,000,000
Consumer, excluding credit card | Current and less than 30 days past due and still accruing | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	20,038,000,000	19,710,000,000
Consumer, excluding credit card | Current and less than 30 days past due and still accruing | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	9,968,000,000	10,080,000,000
Consumer, excluding credit card | Current and less than 30 days past due and still accruing | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	84,962,000,000	83,656,000,000
Consumer, excluding credit card | Days Past Due, 30 to 119 | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	492,000,000	663,000,000
Consumer, excluding credit card | Days Past Due, 30 to 119 | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	199,000,000	208,000,000
Consumer, excluding credit card | Days Past Due, 30 to 119 | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	466,000,000	576,000,000
Consumer, excluding credit card | Days Past Due, 30 to 119 | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	1,157,000,000	1,447,000,000
Consumer, excluding credit card | Days Past Due, 120 or More | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	7,000,000	7,000,000
Consumer, excluding credit card | Days Past Due, 120 or More | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	138,000,000	140,000,000
Consumer, excluding credit card | Days Past Due, 120 or More | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	306,000,000	314,000,000
Consumer, excluding credit card | Days Past Due, 120 or More | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	451,000,000	461,000,000
Consumer, excluding credit card | 90 or more days past due and still accruing | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	0	0
Consumer, excluding credit card | 90 or more days past due and still accruing | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	0	0
Consumer, excluding credit card | 90 or more days past due and still accruing | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	346,000,000	367,000,000
Consumer, excluding credit card | 90 or more days past due and still accruing | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	346,000,000	367,000,000
Consumer, excluding credit card | Nonaccrual | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	95,000,000	115,000,000
Consumer, excluding credit card | Nonaccrual | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	268,000,000	279,000,000
Consumer, excluding credit card | Nonaccrual | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	264,000,000	270,000,000
Consumer, excluding credit card | Nonaccrual | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	627,000,000	664,000,000
Consumer, excluding credit card | Noncriticized | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	10,061,000,000	9,822,000,000
Consumer, excluding credit card | Noncriticized | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	14,842,000,000	14,619,000,000
Consumer, excluding credit card | Noncriticized | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	24,903,000,000	24,441,000,000
Consumer, excluding credit card | Criticized performing | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	83,000,000	35,000,000
Consumer, excluding credit card | Criticized performing | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	714,000,000	708,000,000
Consumer, excluding credit card | Criticized performing | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	797,000,000	743,000,000
Consumer, excluding credit card | Criticized nonaccrual | Auto
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	0	0
Consumer, excluding credit card | Criticized nonaccrual | Business banking
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	212,000,000	213,000,000
Consumer, excluding credit card | Criticized nonaccrual | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	212,000,000	213,000,000
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Current and less than 30 days past due and still accruing | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	4,200,000,000	4,300,000,000
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Days Past Due, 30 to 119 | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	317,000,000	364,000,000
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Days Past Due, 120 or More | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	279,000,000	290,000,000
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Days Past Due, 30 or More, and Still Accruing | Student and other
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	596,000,000	$ 654,000,000
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Minimum | Days Past Due, 30 to 119 | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans, charge-off criteria, period past due	30 days
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Minimum | Days Past Due, 120 or More | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans, charge-off criteria, period past due	120 days
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Minimum | Days Past Due, 30 or More, and Still Accruing | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans, charge-off criteria, period past due	30 days
Consumer, excluding credit card | Student and Other Loans Insured or Guaranteed by U.S. Government Agencies | Maximum | Days Past Due, 30 to 119 | Other Consumer
Loans and Leases Receivable Disclosure [Line Items]
Loans, charge-off criteria, period past due	119 days