Loans - Consumer, Excluding Credit Card Loans, Residential Real Estate, Excluding PCI Loans (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 889,907	$ 832,792	$ 747,508
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Retained	364,406	344,355	$ 294,979
Consumer, excluding credit card | Total residential real estate – excluding PCI
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 231,226	$ 211,798
Total 30 day delinquency rate	1.11%	1.40%
Nonaccrual loans	$ 4,092	$ 4,694
Consumer, excluding credit card | Total residential real estate – excluding PCI | California
Loans and Leases Receivable Disclosure [Line Items]
Retained	67,429	56,208
Consumer, excluding credit card | Total residential real estate – excluding PCI | New York
Loans and Leases Receivable Disclosure [Line Items]
Retained	32,791	30,609
Consumer, excluding credit card | Total residential real estate – excluding PCI | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Retained	16,062	14,944
Consumer, excluding credit card | Total residential real estate – excluding PCI | Texas
Loans and Leases Receivable Disclosure [Line Items]
Retained	12,942	11,660
Consumer, excluding credit card | Total residential real estate – excluding PCI | Florida
Loans and Leases Receivable Disclosure [Line Items]
Retained	10,520	9,586
Consumer, excluding credit card | Total residential real estate – excluding PCI | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Retained	8,624	8,157
Consumer, excluding credit card | Total residential real estate – excluding PCI | Colorado
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,981	6,216
Consumer, excluding credit card | Total residential real estate – excluding PCI | Washington
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,672	5,627
Consumer, excluding credit card | Total residential real estate – excluding PCI | Massachusetts
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,204	5,799
Consumer, excluding credit card | Total residential real estate – excluding PCI | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Retained	5,349	5,298
Consumer, excluding credit card | Total residential real estate – excluding PCI | All other
Loans and Leases Receivable Disclosure [Line Items]
Retained	57,652	57,694
Consumer, excluding credit card | Total residential real estate – excluding PCI | No FICO/LTV available
Loans and Leases Receivable Disclosure [Line Items]
Retained	3,813	4,714
Consumer, excluding credit card | Total residential real estate – excluding PCI | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	100	223
Consumer, excluding credit card | Total residential real estate – excluding PCI | Greater than 125% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	63	109
Consumer, excluding credit card | Total residential real estate – excluding PCI | 101 percent to 125 percent and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	803	1,618
Consumer, excluding credit card | Total residential real estate – excluding PCI | 101 percent to 125 percent and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	398	725
Consumer, excluding credit card | Total residential real estate – excluding PCI | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,987	7,696
Consumer, excluding credit card | Total residential real estate – excluding PCI | 80% to 100% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	1,663	2,405
Consumer, excluding credit card | Total residential real estate – excluding PCI | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	196,896	171,889
Consumer, excluding credit card | Total residential real estate – excluding PCI | Less than 80% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	11,139	11,731
Consumer, excluding credit card | Total residential real estate – excluding PCI | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	9,364	10,688
90 days past due	4,858	6,056
Consumer, excluding credit card | Total residential real estate – excluding PCI | U.S. government-guaranteed | All other
Loans and Leases Receivable Disclosure [Line Items]
Retained	9,400	10,700
Consumer, excluding credit card | Total residential real estate – excluding PCI | Current
Loans and Leases Receivable Disclosure [Line Items]
Retained	221,760	200,762
Consumer, excluding credit card | Total residential real estate – excluding PCI | Current | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,500	2,600
Consumer, excluding credit card | Total residential real estate – excluding PCI | 30–149 days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	4,470	4,750
Consumer, excluding credit card | Total residential real estate – excluding PCI | 30–149 days past due | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	3,100	3,200
Consumer, excluding credit card | Total residential real estate – excluding PCI | 150 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	4,996	6,286
Consumer, excluding credit card | Total residential real estate – excluding PCI | 150 or more days past due | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	3,800	4,900
Consumer, excluding credit card | Total residential real estate – excluding PCI | 30 or more days past due | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,900	8,100
Consumer, excluding credit card | Total residential real estate – excluding PCI | 90 or more days past due | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	2,200	3,400
Consumer, excluding credit card | Home equity
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 39,063	$ 45,559
Total 30 day delinquency rate	2.87%	2.77%
Nonaccrual loans	$ 1,845	$ 2,191
Consumer, excluding credit card | Home equity | California
Loans and Leases Receivable Disclosure [Line Items]
Retained	7,644	8,945
Consumer, excluding credit card | Home equity | New York
Loans and Leases Receivable Disclosure [Line Items]
Retained	7,978	9,147
Consumer, excluding credit card | Home equity | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,947	3,420
Consumer, excluding credit card | Home equity | Texas
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,225	2,532
Consumer, excluding credit card | Home equity | Florida
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,133	2,409
Consumer, excluding credit card | Home equity | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,253	2,590
Consumer, excluding credit card | Home equity | Colorado
Loans and Leases Receivable Disclosure [Line Items]
Retained	677	807
Consumer, excluding credit card | Home equity | Washington
Loans and Leases Receivable Disclosure [Line Items]
Retained	1,229	1,451
Consumer, excluding credit card | Home equity | Massachusetts
Loans and Leases Receivable Disclosure [Line Items]
Retained	371	459
Consumer, excluding credit card | Home equity | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Retained	1,772	2,143
Consumer, excluding credit card | Home equity | All other
Loans and Leases Receivable Disclosure [Line Items]
Retained	9,834	11,656
Consumer, excluding credit card | Home equity | No FICO/LTV available
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,486	3,056
Consumer, excluding credit card | Home equity | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	70	165
Consumer, excluding credit card | Home equity | Greater than 125% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	15	32
Consumer, excluding credit card | Home equity | 101 percent to 125 percent and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	668	1,344
Consumer, excluding credit card | Home equity | 101 percent to 125 percent and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	221	434
Consumer, excluding credit card | Home equity | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	2,961	4,537
Consumer, excluding credit card | Home equity | 80% to 100% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	945	1,409
Consumer, excluding credit card | Home equity | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	27,317	29,648
Consumer, excluding credit card | Home equity | Less than 80% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	4,380	4,934
Consumer, excluding credit card | Home equity | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	0	0
90 days past due	0	0
Consumer, excluding credit card | Home equity | Current
Loans and Leases Receivable Disclosure [Line Items]
Retained	37,941	44,299
Consumer, excluding credit card | Home equity | 30–149 days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	646	708
Consumer, excluding credit card | Home equity | 150 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	476	552
Consumer, excluding credit card | Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 192,163	$ 166,239
Total 30 day delinquency rate	0.75%	1.03%
Nonaccrual loans	$ 2,247	$ 2,503
Consumer, excluding credit card | Residential mortgage | California
Loans and Leases Receivable Disclosure [Line Items]
Retained	59,785	47,263
Consumer, excluding credit card | Residential mortgage | New York
Loans and Leases Receivable Disclosure [Line Items]
Retained	24,813	21,462
Consumer, excluding credit card | Residential mortgage | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Retained	13,115	11,524
Consumer, excluding credit card | Residential mortgage | Texas
Loans and Leases Receivable Disclosure [Line Items]
Retained	10,717	9,128
Consumer, excluding credit card | Residential mortgage | Florida
Loans and Leases Receivable Disclosure [Line Items]
Retained	8,387	7,177
Consumer, excluding credit card | Residential mortgage | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,371	5,567
Consumer, excluding credit card | Residential mortgage | Colorado
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,304	5,409
Consumer, excluding credit card | Residential mortgage | Washington
Loans and Leases Receivable Disclosure [Line Items]
Retained	5,443	4,176
Consumer, excluding credit card | Residential mortgage | Massachusetts
Loans and Leases Receivable Disclosure [Line Items]
Retained	5,833	5,340
Consumer, excluding credit card | Residential mortgage | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Retained	3,577	3,155
Consumer, excluding credit card | Residential mortgage | All other
Loans and Leases Receivable Disclosure [Line Items]
Retained	47,818	46,038
Consumer, excluding credit card | Residential mortgage | No FICO/LTV available
Loans and Leases Receivable Disclosure [Line Items]
Retained	1,327	1,658
Consumer, excluding credit card | Residential mortgage | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	30	58
Consumer, excluding credit card | Residential mortgage | Greater than 125% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	48	77
Consumer, excluding credit card | Residential mortgage | 101 percent to 125 percent and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	135	274
Consumer, excluding credit card | Residential mortgage | 101 percent to 125 percent and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	177	291
Consumer, excluding credit card | Residential mortgage | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	4,026	3,159
Consumer, excluding credit card | Residential mortgage | 80% to 100% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	718	996
Consumer, excluding credit card | Residential mortgage | Less than 80% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	169,579	142,241
Consumer, excluding credit card | Residential mortgage | Less than 80% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained	6,759	6,797
Consumer, excluding credit card | Residential mortgage | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained	9,364	10,688
90 days past due	4,858	6,056
Consumer, excluding credit card | Residential mortgage | Current
Loans and Leases Receivable Disclosure [Line Items]
Retained	183,819	156,463
Consumer, excluding credit card | Residential mortgage | 30–149 days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	3,824	4,042
Consumer, excluding credit card | Residential mortgage | 150 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Retained	$ 4,520	$ 5,734