Loans - Consumer Loans excluding Credit Card, FICO and LTV (Details 6b) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	$ 712,898	$ 718,997	$ 675,437
Residential real estate, excluding PCI [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	160,788	163,660
Loans guaranteed by the U.S. government	15,842	15,584
Residential real estate, excluding PCI [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	10,124	10,339
Residential real estate, excluding PCI [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	4,482	4,674
Residential real estate, excluding PCI [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	5,566	5,671
Residential real estate, excluding PCI [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	14,114	14,570
Residential real estate, excluding PCI [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	22,180	23,443
Residential real estate, excluding PCI [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	6,907	7,122
Residential real estate, excluding PCI [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	69,628	70,431
Residential real estate, excluding PCI [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	11,945	11,826
Subprime Mortgage [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	9,289	9,664
Loans guaranteed by the U.S. government	0	0
Subprime Mortgage [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	361	367
Subprime Mortgage [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,007	1,061
Subprime Mortgage [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	502	506
Subprime Mortgage [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,219	1,284
Subprime Mortgage [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	801	817
Subprime Mortgage [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,446	1,556
Subprime Mortgage [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,854	1,906
Subprime Mortgage [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,099	2,167
Prime Mortgages, including option ARMs [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	76,292	76,196
Loans guaranteed by the U.S. government	15,842	15,584
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	3,137	3,168
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,323	1,416
Prime Mortgages, including option ARMs [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	4,601	4,626
Prime Mortgages, including option ARMs [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,672	1,636
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	8,730	9,343
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,331	2,349
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	34,281	33,849
Prime Mortgages, including option ARMs [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	4,375	4,225
Home Equity Senior Lien [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	21,202	21,765
Loans guaranteed by the U.S. government	0	0
Home Equity Senior Lien [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	317	341
Home Equity Senior Lien [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	152	160
Home Equity Senior Lien [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	652	663
Home Equity Senior Lien [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	247	241
Home Equity Senior Lien [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	1,771	1,850
Home Equity Senior Lien [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	593	601
Home Equity Senior Lien [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	14,908	15,350
Home Equity Senior Lien [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,562	2,559
Home Equity Junior Lien [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	54,005	56,035
Loans guaranteed by the U.S. government	0	0
Home Equity Junior Lien [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	6,309	6,463
Home Equity Junior Lien [Member] | Current Estimated LTV Greater Than 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,000	2,037
Home Equity Junior Lien [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	8,359	8,775
Home Equity Junior Lien [Member] | Current Estimated Ltv Between 101% And 125% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,428	2,510
Home Equity Junior Lien [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	10,878	11,433
Home Equity Junior Lien [Member] | Current Estimated LTV Between 80% To 100% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	2,537	2,616
Home Equity Junior Lien [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Equal to or greater than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	18,585	19,326
Home Equity Junior Lien [Member] | Current Estimated LTV Less Than 80% [Member] | Refreshed FICO Scores Less than 660 [Member]
Consumer Loans Excluding Credit Card Portfolio Segment, by Class, by FICO Score, by LTV Ratio [Line Items]
Retained loans	$ 2,909	$ 2,875