Loans and Allowance for Credit Losses (Details 7) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012 Loans	Jun. 30, 2011 Loans	Jun. 30, 2012 Loans	Jun. 30, 2011 Loans
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	3,309	2,347	6,633	4,731
Amount Defaulted	$ 184	$ 55	$ 420	$ 164
Commercial Loan [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	216	179	457	268
Amount Defaulted	10	5	31	10
Commercial Real Estate Loans [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	29	8	83	8
Amount Defaulted	72	5	164	5
Residential Mortgage [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	247	97	311	440
Amount Defaulted	22	18	34	92
Credit Card [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	2,390	1,850	4,916	3,563
Amount Defaulted	13	10	28	18
Other Retail [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	158	116	342	199
Amount Defaulted	1	2	4	4
Total loans, excluding GNMA and covered loans [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	3,040	2,250	6,109	4,478
Amount Defaulted	118	40	261	129
Loans purchased from GNMA [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	262	97	483	253
Amount Defaulted	39	15	72	35
Covered Financing Receivable [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	7		41
Amount Defaulted	$ 27		$ 87