Fair Values of Assets and Liabilities (Details 5) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Losses recognized related to nonrecurring fair value measurements of individual assets or portfolios
Loans	$ 21	$ 106	$ 39	$ 121
Other assets	$ 40	$ 62	$ 87	$ 149