Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income	$ 674		$ 555		$ 1,591		$ 1,539
Less: Preferred stock dividends	(15)	[1]	(6)	[1]	(29)	[1]	(13)	[1]
Less: Dividends and undistributed earnings allocated to participating securities	(5)	[2]	(6)	[2]	(11)	[2]	(15)	[2]
Net income available to common shareholders	654		543		1,551		1,511
Basic average common shares	472,355		490,840		479,536		495,015
Effect of dilutive securities: common stock options and common stock awards	7,655		3,940		6,277		3,402
Diluted average shares	480,010		494,780		485,813		498,417
Anti-dilutive securities	5,443	[3]	3,636	[3]	5,613	[3]	2,589	[3]
Earnings Per Share, Basic	$ 1.39		$ 1.11		$ 3.23		$ 3.05
Earnings Per Share, Diluted	$ 1.36	[4]	$ 1.10	[4]	$ 3.19	[4]	$ 3.03	[4]
Series C Preferred Stock [Member]
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Less: Preferred stock dividends	$ (8)				$ (8)

[1] Three and nine months ended September 30, 2012 included $8 million related to Series C preferred stock issued in August 2012. Remaining amounts for 2012 periods, and amounts for three and nine months ended September 30, 2011, related to Series A preferred stock, which was redeemed on October 4, 2012.

[2] Represented the portion of net income available to common equity allocated to participating securities; participating securities, composed of unvested restricted stock and director stock, have non-forfeitable rights to dividends during the vesting period on a basis equivalent to dividends paid to common shareholders.

[3] Represented common stock options and other equity-based awards outstanding, but not included in the computation of diluted average shares because their effect was anti-dilutive.

[4] Calculations reflect allocation of earnings to participating securities using the two-class method, as this computation is more dilutive than the calculation using the treasury stock method.