Loans - Consumer, Excluding Credit Card Loans, PCI Loans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	$ 747,508	$ 724,177	$ 726,835
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	294,979	288,449	292,620
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	17,095	18,927
Related allowance for loan losses	1,758	1,758
Total loans	17,740	19,830
% of 30 days past due to total loans	8.15%	8.55%
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	10,671	11,937
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	876	962
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	405	451
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,696	1,865
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	273	327
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	348	381
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	323	361
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	959	1,072
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	53	62
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	20	23
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,116	2,389
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	16,295	18,135
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	445	583
Consumer, excluding credit card | Purchased Credit-Impaired, Home Equity | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,000	1,112
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	513	1,168
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	2,245	3,248
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	4,171	4,473
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	5,824	5,077
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	273	662
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	1,073	1,541
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	1,647	1,782
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	1,994	1,879
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	10,220	12,038
Related allowance for loan losses	1,193	1,726
Total loans	10,249	11,876
% of 30 days past due to total loans	13.05%	14.80%
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	5,965	6,845
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	672	807
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	301	353
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	689	826
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	92	106
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	279	334
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	167	187
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	225	266
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	166	189
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	48	55
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,645	1,908
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	8,912	10,118
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	500	589
Consumer, excluding credit card | Purchased Credit-Impaired, Prime Mortgage | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	837	1,169
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	45	240
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	456	1,017
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	2,154	2,787
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	3,663	2,897
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	97	290
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	402	884
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	1,316	1,699
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	2,116	2,062
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	3,673	4,175
Related allowance for loan losses	180	180
Total loans	4,652	5,471
% of 30 days past due to total loans	23.37%	26.67%
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,138	1,293
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	463	563
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	229	283
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	432	526
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	281	328
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	165	213
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	85	95
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	95	112
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	130	145
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	72	84
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,562	1,829
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	3,565	4,012
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	536	662
Consumer, excluding credit card | Purchased Credit-Impaired, Subprime Mortgage | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	551	797
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	34	115
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	215	316
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	519	544
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	719	521
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	160	459
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	509	919
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	1,006	1,197
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	1,490	1,400
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs
Loans and Leases Receivable Disclosure [Line Items]
Total retained loans	15,708	17,915
Related allowance for loan losses	194	494
Total loans	16,496	19,223
% of 30 days past due to total loans	16.26%	19.36%
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	9,190	10,419
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	933	1,196
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	397	481
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,440	1,817
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	85	100
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	553	701
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	227	264
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	395	463
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	182	206
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	69	75
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	3,025	3,501
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	13,814	15,501
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	858	1,006
Consumer, excluding credit card | Purchased Credit-Impaired, Option ARMs | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,824	2,716
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	89	301
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	575	1,164
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	2,418	3,311
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	6,593	5,671
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	150	575
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	771	1,563
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	1,996	2,769
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	3,904	3,869
Consumer, excluding credit card | Purchased Credit-Impaired
Loans and Leases Receivable Disclosure [Line Items]
Weighted Average Life of PCI Portfolio	8 years
Total retained loans	46,696	53,055
Related allowance for loan losses	3,325	4,158
Total loans	49,137	56,400
% of 30 days past due to total loans	13.33%	15.31%
Consumer, excluding credit card | Purchased Credit-Impaired | California
Loans and Leases Receivable Disclosure [Line Items]
Total loans	26,964	30,494
Consumer, excluding credit card | Purchased Credit-Impaired | New York
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,944	3,528
Consumer, excluding credit card | Purchased Credit-Impaired | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,332	1,568
Consumer, excluding credit card | Purchased Credit-Impaired | Florida
Loans and Leases Receivable Disclosure [Line Items]
Total loans	4,257	5,034
Consumer, excluding credit card | Purchased Credit-Impaired | Texas
Loans and Leases Receivable Disclosure [Line Items]
Total loans	731	861
Consumer, excluding credit card | Purchased Credit-Impaired | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,345	1,629
Consumer, excluding credit card | Purchased Credit-Impaired | Arizona
Loans and Leases Receivable Disclosure [Line Items]
Total loans	802	907
Consumer, excluding credit card | Purchased Credit-Impaired | Washington
Loans and Leases Receivable Disclosure [Line Items]
Total loans	1,674	1,913
Consumer, excluding credit card | Purchased Credit-Impaired | Michigan
Loans and Leases Receivable Disclosure [Line Items]
Total loans	531	602
Consumer, excluding credit card | Purchased Credit-Impaired | Ohio
Loans and Leases Receivable Disclosure [Line Items]
Total loans	209	237
Consumer, excluding credit card | Purchased Credit-Impaired | All other
Loans and Leases Receivable Disclosure [Line Items]
Total loans	8,348	9,627
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	42,586	47,766
Consumer, excluding credit card | Purchased Credit-Impaired | Days Past Due, 30 to 149
Loans and Leases Receivable Disclosure [Line Items]
Total loans	2,339	2,840
Consumer, excluding credit card | Purchased Credit-Impaired | 150 days past due
Loans and Leases Receivable Disclosure [Line Items]
Total loans	4,212	5,794
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	681	1,824
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	3,491	5,745
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	9,262	11,115
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	16,799	14,166
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	680	1,986
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	2,755	4,907
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	5,965	7,447
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	$ 9,504	$ 9,210