Asset Quality (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Concession types for our commercial accruing and nonaccruing TDRs
Interest rate reduction	$ 184	$ 177	$ 165
Forgiveness of principal	11	23	10
Other modification of loan terms	22	8	7
Total	217	208	182
Total commercial and consumer TDRs	293	276	242
Total commercial TDRs to total commercial loans	0.63%	0.60%	0.55%
Total commercial TDRs to total loans	0.44%	0.42%	0.37%
Total commercial loans	34,622	34,782	33,298
Total loans	$ 49,226	$ 49,575	$ 48,552