Fair Values of Assets and Liabilities (Details 3) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Adjusted carrying values for assets measured at fair value on a nonrecurring basis
Loans	$ 151	$ 405
Other real estate owned	275	812
Other intangible assets	0	1
Other assets	0	13
Level 1 [Member]
Adjusted carrying values for assets measured at fair value on a nonrecurring basis
Loans	0	0
Other real estate owned	0	0
Other intangible assets	0	0
Other assets	0	0
Level 2 [Member]
Adjusted carrying values for assets measured at fair value on a nonrecurring basis
Loans	151	404
Other real estate owned	275	812
Other intangible assets	0	0
Other assets	0	4
Level 3 [Member]
Adjusted carrying values for assets measured at fair value on a nonrecurring basis
Loans	0	1
Other real estate owned	0	0
Other intangible assets	0	1
Other assets	$ 0	$ 9