Loans and Allowance for Credit Losses (Details 7) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 Loans	Mar. 31, 2011 Loans
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	3,324	2,384
Amount Defaulted	$ 236	$ 109
Commercial Loan [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	241	89
Amount Defaulted	21	5
Commercial Real Estate Loans [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	54
Amount Defaulted	92
Residential Mortgage [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	64	343
Amount Defaulted	12	74
Credit Card [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	2,526	1,713
Amount Defaulted	15	8
Other Retail [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	184	83
Amount Defaulted	3	2
Total loans, excluding GNMA and covered loans [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	3,069	2,228
Amount Defaulted	143	89
Loans purchased from GNMA [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	221	156
Amount Defaulted	33	20
Covered Financing Receivable [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	34
Amount Defaulted	$ 60