Loans - Other Consumer Loans, by Delinquency, Geography and Risk (Details 7) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	$ 712,898	$ 718,997	$ 675,437
Student And Other Loans Thirty Or More Days Past Due And Still Accruing Insured By Us Government Agencies Under The Federal Family Education Loan Program	1,045	989
Other Consumer [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	79,921	79,221
Percentage Of Loans Thirty Plus Days Past Due To Total Retained Loans	1.40%	1.59%
Other Consumer [Member] | Noncriticized [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	19,502	18,524
Other Consumer [Member] | Criticized Performing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	935	983
Other Consumer [Member] | Criticized Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	511	527
Other Consumer [Member] | California [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	7,271	7,016
Other Consumer [Member] | New York [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	7,866	7,809
Other Consumer [Member] | Florida [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,942	2,852
Other Consumer [Member] | Illinois [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	4,803	4,711
Other Consumer [Member] | Texas [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	8,219	8,200
Other Consumer [Member] | New Jersey [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,707	2,665
Other Consumer [Member] | Arizona [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,975	2,976
Other Consumer [Member] | Washington [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,171	1,144
Other Consumer [Member] | Ohio [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	5,036	5,054
Other Consumer [Member] | Michigan [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	4,268	4,308
Other Consumer [Member] | All Other States [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	32,663	32,486
Other Consumer [Member] | Current and less than 30 days past due and still accruing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	77,760	76,969
Other Consumer [Member] | 30-119 days past due [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,508	1,631
Other Consumer [Member] | Days Past Due, 120 or More [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	653	621
Other Consumer [Member] | Past Due And Still Accruing 90 Days Or More Member
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	586	551
Other Consumer [Member] | Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	856	881
Consumer Loans Auto Financing Receivable [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	48,245	47,426
Percentage Of Loans Thirty Plus Days Past Due To Total Retained Loans	0.79%	1.13%
Consumer Loans Auto Financing Receivable [Member] | Noncriticized [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	7,474	6,775
Consumer Loans Auto Financing Receivable [Member] | Criticized Performing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	161	166
Consumer Loans Auto Financing Receivable [Member] | Criticized Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	6	3
Consumer Loans Auto Financing Receivable [Member] | California [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	4,569	4,413
Consumer Loans Auto Financing Receivable [Member] | New York [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	3,722	3,616
Consumer Loans Auto Financing Receivable [Member] | Florida [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,928	1,881
Consumer Loans Auto Financing Receivable [Member] | Illinois [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,601	2,496
Consumer Loans Auto Financing Receivable [Member] | Texas [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	4,511	4,467
Consumer Loans Auto Financing Receivable [Member] | New Jersey [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,879	1,829
Consumer Loans Auto Financing Receivable [Member] | Arizona [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,521	1,495
Consumer Loans Auto Financing Receivable [Member] | Washington [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	749	735
Consumer Loans Auto Financing Receivable [Member] | Ohio [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,648	2,633
Consumer Loans Auto Financing Receivable [Member] | Michigan [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,256	2,282
Consumer Loans Auto Financing Receivable [Member] | All Other States [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	21,861	21,579
Consumer Loans Auto Financing Receivable [Member] | Current and less than 30 days past due and still accruing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	47,866	46,891
Consumer Loans Auto Financing Receivable [Member] | 30-119 days past due [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	374	528
Consumer Loans Auto Financing Receivable [Member] | Days Past Due, 120 or More [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	5	7
Consumer Loans Auto Financing Receivable [Member] | Past Due And Still Accruing 90 Days Or More Member
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	0	0
Consumer Loans Auto Financing Receivable [Member] | Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	102	118
Consumer business banking
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	17,822	17,652
Percentage Of Loans Thirty Plus Days Past Due To Total Retained Loans	2.57%	2.71%
Consumer business banking | Noncriticized [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	12,028	11,749
Consumer business banking | Criticized Performing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	774	817
Consumer business banking | Criticized Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	505	524
Consumer business banking | California [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,449	1,342
Consumer business banking | New York [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,765	2,792
Consumer business banking | Florida [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	372	313
Consumer business banking | Illinois [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,367	1,364
Consumer business banking | Texas [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	2,700	2,680
Consumer business banking | New Jersey [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	374	376
Consumer business banking | Arizona [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,146	1,165
Consumer business banking | Washington [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	176	160
Consumer business banking | Ohio [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,526	1,541
Consumer business banking | Michigan [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,388	1,389
Consumer business banking | All Other States [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	4,559	4,530
Consumer business banking | Current and less than 30 days past due and still accruing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	17,364	17,173
Consumer business banking | 30-119 days past due [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	283	326
Consumer business banking | Days Past Due, 120 or More [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	175	153
Consumer business banking | Past Due And Still Accruing 90 Days Or More Member
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	0	0
Consumer business banking | Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	649	694
Student And Other Loans [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	13,854	14,143
Percentage Of Loans Thirty Plus Days Past Due To Total Retained Loans	2.01%	1.76%
Student And Other Loans [Member] | California [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,253	1,261
Student And Other Loans [Member] | New York [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,379	1,401
Student And Other Loans [Member] | Florida [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	642	658
Student And Other Loans [Member] | Illinois [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	835	851
Student And Other Loans [Member] | Texas [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	1,008	1,053
Student And Other Loans [Member] | New Jersey [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	454	460
Student And Other Loans [Member] | Arizona [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	308	316
Student And Other Loans [Member] | Washington [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	246	249
Student And Other Loans [Member] | Ohio [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	862	880
Student And Other Loans [Member] | Michigan [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	624	637
Student And Other Loans [Member] | All Other States [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	6,243	6,377
Student And Other Loans [Member] | Current and less than 30 days past due and still accruing [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	12,530	12,905
Student And Other Loans [Member] | 30-119 days past due [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	851	777
Student And Other Loans [Member] | Days Past Due, 120 or More [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	473	461
Student And Other Loans [Member] | Past Due And Still Accruing 90 Days Or More Member
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	586	551
Student And Other Loans [Member] | Nonaccrual [Member]
Schedule of Loan Credit Quality, by Portfolio Segment and Class, by Geography, Delinquency, Risk Rating [Line Items]
Retained loans	$ 105	$ 69