Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate, Excluding PCI Loans (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 844,195,000,000	$ 832,792,000,000	$ 756,971,000,000
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	43,932,000,000	45,559,000,000
Consumer, excluding credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 353,871,000,000	$ 344,355,000,000	$ 304,917,000,000
Period past due, credit analysis factors, charge off criteria	90 days	90 days
Consumer, excluding credit card | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 220,038,000,000	$ 211,798,000,000
% of 30 days past due to total retained loans	1.27%	1.40%
Consumer, excluding credit card | Residential real estate | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 59,971,000,000	$ 56,208,000,000
Consumer, excluding credit card | Residential real estate | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	31,245,000,000	30,609,000,000
Consumer, excluding credit card | Residential real estate | Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	15,473,000,000	14,944,000,000
Consumer, excluding credit card | Residential real estate | Texas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	12,148,000,000	11,660,000,000
Consumer, excluding credit card | Residential real estate | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	9,950,000,000	9,586,000,000
Consumer, excluding credit card | Residential real estate | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	8,386,000,000	8,157,000,000
Consumer, excluding credit card | Residential real estate | Washington
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	5,881,000,000	5,627,000,000
Consumer, excluding credit card | Residential real estate | Arizona
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	5,391,000,000	5,298,000,000
Consumer, excluding credit card | Residential real estate | Michigan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,312,000,000	3,295,000,000
Consumer, excluding credit card | Residential real estate | Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,889,000,000	2,899,000,000
Consumer, excluding credit card | Residential real estate | All other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	65,392,000,000	63,515,000,000
Consumer, excluding credit card | Residential real estate | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	10,554,000,000	10,688,000,000
Consumer, excluding credit card | Residential real estate | No FICO/LTV available
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,759,000,000	4,714,000,000
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	184,000,000	223,000,000
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	93,000,000	109,000,000
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,266,000,000	1,618,000,000
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	600,000,000	725,000,000
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	6,969,000,000	7,696,000,000
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,155,000,000	2,405,000,000
Consumer, excluding credit card | Residential real estate | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	181,680,000,000	171,889,000,000
Consumer, excluding credit card | Residential real estate | Less than 80% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	11,778,000,000	11,731,000,000
Consumer, excluding credit card | Residential real estate | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	209,809,000,000	200,762,000,000
Consumer, excluding credit card | Residential real estate | Current | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,100,000,000	2,600,000,000
Consumer, excluding credit card | Residential real estate | 30–149 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,222,000,000	4,750,000,000
Consumer, excluding credit card | Residential real estate | 30–149 days past due | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 2,800,000,000	3,200,000,000
Consumer, excluding credit card | Residential real estate | 30–149 days past due | U.S. government-guaranteed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period past due, credit analysis factors, charge off criteria	30 days
Consumer, excluding credit card | Residential real estate | 30–149 days past due | U.S. government-guaranteed | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period past due, credit analysis factors, charge off criteria	149 days
Consumer, excluding credit card | Residential real estate | 150 or more days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 6,007,000,000	6,286,000,000
Consumer, excluding credit card | Residential real estate | 150 or more days past due | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 4,700,000,000	4,900,000,000
Consumer, excluding credit card | Residential real estate | 150 or more days past due | U.S. government-guaranteed | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period past due, credit analysis factors, charge off criteria	150 days
Consumer, excluding credit card | Residential real estate | 90 or more days past due and government guaranteed | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 5,555,000,000	6,056,000,000
Consumer, excluding credit card | Residential real estate | Nonaccrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,576,000,000	4,694,000,000
Consumer, excluding credit card | Residential real estate | Nonaccrual loans | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,200,000,000	3,400,000,000
Consumer, excluding credit card | Residential real estate | 90 or more days past due and still accruing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 0	$ 0
Consumer, excluding credit card | Residential real estate | 90 or more days past due and still accruing | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period past due, credit analysis factors, charge off criteria	90 days	90 days
Consumer, excluding credit card | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 43,932,000,000	$ 45,559,000,000
% of 30 days past due to total retained loans	2.66%	2.77%
Consumer, excluding credit card | Home equity | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 8,618,000,000	$ 8,945,000,000
Consumer, excluding credit card | Home equity | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	8,810,000,000	9,147,000,000
Consumer, excluding credit card | Home equity | Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,292,000,000	3,420,000,000
Consumer, excluding credit card | Home equity | Texas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,437,000,000	2,532,000,000
Consumer, excluding credit card | Home equity | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,418,000,000	2,409,000,000
Consumer, excluding credit card | Home equity | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,514,000,000	2,590,000,000
Consumer, excluding credit card | Home equity | Washington
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,398,000,000	1,451,000,000
Consumer, excluding credit card | Home equity | Arizona
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,053,000,000	2,143,000,000
Consumer, excluding credit card | Home equity | Michigan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,296,000,000	1,350,000,000
Consumer, excluding credit card | Home equity | Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,587,000,000	1,652,000,000
Consumer, excluding credit card | Home equity | All other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	9,509,000,000	9,920,000,000
Consumer, excluding credit card | Home equity | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	0	0
Consumer, excluding credit card | Home equity | No FICO/LTV available
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,874,000,000	3,056,000,000
Consumer, excluding credit card | Home equity | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	129,000,000	165,000,000
Consumer, excluding credit card | Home equity | Greater than 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	30,000,000	32,000,000
Consumer, excluding credit card | Home equity | 101% to 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,051,000,000	1,344,000,000
Consumer, excluding credit card | Home equity | 101% to 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	347,000,000	434,000,000
Consumer, excluding credit card | Home equity | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,096,000,000	4,537,000,000
Consumer, excluding credit card | Home equity | 80% to 100% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,260,000,000	1,409,000,000
Consumer, excluding credit card | Home equity | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	29,228,000,000	29,648,000,000
Consumer, excluding credit card | Home equity | Less than 80% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,917,000,000	4,934,000,000
Consumer, excluding credit card | Home equity | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	42,765,000,000	44,299,000,000
Consumer, excluding credit card | Home equity | 30–149 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	626,000,000	708,000,000
Consumer, excluding credit card | Home equity | 150 or more days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	541,000,000	552,000,000
Consumer, excluding credit card | Home equity | 90 or more days past due and government guaranteed | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	0	0
Consumer, excluding credit card | Home equity | Nonaccrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,153,000,000	2,191,000,000
Consumer, excluding credit card | Residential Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 176,106,000,000	$ 166,239,000,000
% of 30 days past due to total retained loans	0.93%	1.03%
Consumer, excluding credit card | Residential Mortgage | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 51,353,000,000	$ 47,263,000,000
Consumer, excluding credit card | Residential Mortgage | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	22,435,000,000	21,462,000,000
Consumer, excluding credit card | Residential Mortgage | Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	12,181,000,000	11,524,000,000
Consumer, excluding credit card | Residential Mortgage | Texas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	9,711,000,000	9,128,000,000
Consumer, excluding credit card | Residential Mortgage | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	7,532,000,000	7,177,000,000
Consumer, excluding credit card | Residential Mortgage | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	5,872,000,000	5,567,000,000
Consumer, excluding credit card | Residential Mortgage | Washington
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	4,483,000,000	4,176,000,000
Consumer, excluding credit card | Residential Mortgage | Arizona
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,338,000,000	3,155,000,000
Consumer, excluding credit card | Residential Mortgage | Michigan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,016,000,000	1,945,000,000
Consumer, excluding credit card | Residential Mortgage | Ohio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,302,000,000	1,247,000,000
Consumer, excluding credit card | Residential Mortgage | All other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	55,883,000,000	53,595,000,000
Consumer, excluding credit card | Residential Mortgage | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	10,554,000,000	10,688,000,000
Consumer, excluding credit card | Residential Mortgage | U.S. government-guaranteed | All other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	10,600,000,000	10,700,000,000
Consumer, excluding credit card | Residential Mortgage | No FICO/LTV available
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	1,885,000,000	1,658,000,000
Consumer, excluding credit card | Residential Mortgage | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	55,000,000	58,000,000
Consumer, excluding credit card | Residential Mortgage | Greater than 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	63,000,000	77,000,000
Consumer, excluding credit card | Residential Mortgage | 101% to 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	215,000,000	274,000,000
Consumer, excluding credit card | Residential Mortgage | 101% to 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	253,000,000	291,000,000
Consumer, excluding credit card | Residential Mortgage | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,873,000,000	3,159,000,000
Consumer, excluding credit card | Residential Mortgage | 80% to 100% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	895,000,000	996,000,000
Consumer, excluding credit card | Residential Mortgage | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	152,452,000,000	142,241,000,000
Consumer, excluding credit card | Residential Mortgage | Less than 80% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	6,861,000,000	6,797,000,000
Consumer, excluding credit card | Residential Mortgage | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	167,044,000,000	156,463,000,000
Consumer, excluding credit card | Residential Mortgage | 30–149 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	3,596,000,000	4,042,000,000
Consumer, excluding credit card | Residential Mortgage | 150 or more days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	5,466,000,000	5,734,000,000
Consumer, excluding credit card | Residential Mortgage | 90 or more days past due and government guaranteed | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	5,555,000,000	6,056,000,000
Consumer, excluding credit card | Residential Mortgage | Nonaccrual loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	2,423,000,000	2,503,000,000
Consumer, excluding credit card | Residential Mortgage | Nonaccrual loans | U.S. government-guaranteed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total retained loans	$ 7,500,000,000	$ 8,100,000,000