Shareholders' Equity (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended		3 Months Ended	6 Months Ended
	Apr. 30, 2011	Nov. 30, 2008	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2008 Series B Preferred Stock [Member]	Jun. 30, 2011 Series B Preferred Stock [Member]	Jun. 30, 2012 Common Stock [Member]	Jun. 30, 2012 Common Stock [Member] Maximum [Member]
Shareholders' Equity (Textual) [Abstract]
Common Stock general repurchase program					$ 312						$ 230
Treasury Stock, Value										2,500		344
Common Stock repurchase program											259
Common Stock employee compensation and benefit program					32						29
Issuance of preferred stock to the U.S. Treasury									2,500
Shareholders' Equity (Additional Textual) [Abstract]
Amortization of discount on preferred stock including deemed dividend				49
Warrants repurchased	70					70
Repurchases from shares on the open market					82
Repurchases from employees in connection with employee elections under compensation and benefit programs					3
Elimination of dividends			31
Discount amortization			4					140
Amount paid to US treasury during the investment period							2,867
Return to US treasury above initial investment		$ 367