Loans - Consumer, Excluding Credit Card Loans, PCI Loans (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 779,705	$ 747,508	$ 735,369
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	316,781	294,979	$ 288,214
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	16,088	17,095
Related allowance for loan losses	1,758	1,758
Total loans	$ 16,496	$ 17,740
% of 30 days past due to total loans	6.58%	8.15%
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 9,908	$ 10,671
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	833	876
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	382	405
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	248	273
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,581	1,696
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	329	348
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	299	323
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	889	959
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	49	53
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	18	20
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,960	2,116
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Total loans	15,411	16,295
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	326	445
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	759	1,000
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	350	513
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,788	2,245
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,868	4,171
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	5,979	5,824
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	180	273
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	835	1,073
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,490	1,647
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,006	1,994
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	9,553	10,220
Related allowance for loan losses	1,083	1,193
Total loans	$ 9,580	$ 10,249
% of 30 days past due to total loans	11.56%	13.05%
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 5,591	$ 5,965
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	647	672
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	282	301
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	85	92
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	625	689
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	263	279
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	155	167
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	208	225
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	154	166
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	45	48
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,525	1,645
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Total loans	8,473	8,912
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	395	500
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	712	837
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	24	45
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	308	456
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,674	2,154
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,894	3,663
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	58	97
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	282	402
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,100	1,316
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,240	2,116
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,449	3,673
Related allowance for loan losses	180	180
Total loans	$ 4,331	$ 4,652
% of 30 days past due to total loans	21.13%	23.37%
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 1,077	$ 1,138
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	422	463
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	211	229
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	259	281
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	399	432
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	150	165
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	82	85
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	87	95
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	121	130
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	68	72
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,455	1,562
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,416	3,565
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	451	536
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	464	551
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	21	34
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	143	215
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	456	519
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	785	719
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	103	160
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	367	509
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	879	1,006
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,577	1,490
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	14,716	15,708
Related allowance for loan losses	194	194
Total loans	$ 15,338	$ 16,496
% of 30 days past due to total loans	14.49%	16.26%
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 8,634	$ 9,190
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	856	933
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	357	397
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	81	85
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,298	1,440
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	505	553
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	215	227
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	360	395
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	168	182
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	65	69
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,799	3,025
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Total loans	13,116	13,814
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	707	858
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,515	1,824
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	54	89
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	392	575
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,937	2,418
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	6,762	6,593
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	86	150
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	528	771
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,640	1,996
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,939	3,904
Consumer, excluding credit card | Purchased Credit-Impaired
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	43,806	46,696
Related allowance for loan losses	3,215	3,325
Total loans	$ 45,745	$ 49,137
% of 30 days past due to total loans	11.65%	13.33%
Consumer, excluding credit card | Purchased Credit-Impaired | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 25,210	$ 26,964
Consumer, excluding credit card | Purchased Credit-Impaired | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,758	2,944
Consumer, excluding credit card | Purchased Credit-Impaired | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,232	1,332
Consumer, excluding credit card | Purchased Credit-Impaired | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	673	731
Consumer, excluding credit card | Purchased Credit-Impaired | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,903	4,257
Consumer, excluding credit card | Purchased Credit-Impaired | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,247	1,345
Consumer, excluding credit card | Purchased Credit-Impaired | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	751	802
Consumer, excluding credit card | Purchased Credit-Impaired | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,544	1,674
Consumer, excluding credit card | Purchased Credit-Impaired | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	492	531
Consumer, excluding credit card | Purchased Credit-Impaired | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	196	209
Consumer, excluding credit card | Purchased Credit-Impaired | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,739	8,348
Consumer, excluding credit card | Purchased Credit-Impaired | Current and less than 30 days past due and still accruing
Loans and Leases Receivable Disclosure [Line Items]
Total loans	40,416	42,586
Consumer, excluding credit card | Purchased Credit-Impaired | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,879	2,339
Consumer, excluding credit card | Purchased Credit-Impaired | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,450	4,212
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	449	681
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,631	3,491
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	7,935	9,262
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Equal to or Greater than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	17,420	16,799
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Greater than 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	427	680
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 101% and 125%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,012	2,755
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Between 80% and 100%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	5,109	5,965
Consumer, excluding credit card | Purchased Credit-Impaired | Refreshed FICO Scores Less than 660 | Current Estimated LTV Ratio Less than 80%
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 9,762	$ 9,504