Credit Quality and Allowance for Credit Losses (Nonaccrual, Reduced-Rate Loans and Foreclosed Property) (Details) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Nonaccrual loans	$ 941		$ 1,080
Reduced-rate loans	33	[1]	43	[1]
Total nonperforming loans	974		1,123
Foreclosed property	70		112
Total nonperforming assets	1,044		1,235
Business Loans [Member]
Nonaccrual loans	868		1,007
Reduced-rate loans	13		26
Retail Loans [Member]
Nonaccrual loans	73		73
Reduced-rate loans	$ 20		$ 17

[1] Reduced-rate business loans totaled $13 million and $26 million, respectively, and reduced-rate retail loans totaled $20 million and $17 million, respectively, at June 30, 2011 and December 31, 2010.