Loans and Allowance for Credit Losses (Details 8) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2011 Loans	Sep. 30, 2011 Loans
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	2,944	8,256
Amount Defaulted	$ 111	$ 278
Commercial Loan [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	245	513
Amount Defaulted	13	23
Commercial Real Estate Loans [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	29	37
Amount Defaulted	32	37
Residential Mortgage [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	318	1,011
Amount Defaulted	51	178
Credit Card [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	2,183	6,304
Amount Defaulted	12	34
Other Retail [Member]
Loans modified as TDRs have subsequently been fully or partially charged-off
Number of Loans	169	391
Amount Defaulted	$ 3	$ 6