Earnings Per Common Share (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended						1 Months Ended	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Aug. 31, 2012 Series C Preferred Stock	Dec. 31, 2012 Series C Preferred Stock
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net income	$ 2,061		$ 1,920		$ 1,556
Less: Preferred stock dividends	(29)	[1]	(20)	[1]	0	[1]	(8)	(8)
Less: Dividends and undistributed earnings allocated to participating securities	(13)	[2]	(18)	[2]	(16)	[2]
Net income available to common shareholders	$ 2,019		$ 1,882		$ 1,540
Basic average common shares	474,458		492,598		495,394
Effect of dilutive securities: common stock options and common stock awards	6,671		3,474		2,530
Diluted average shares	481,129		496,072		497,924
Anti-dilutive securities	5,619	[3]	2,382	[3]	10,316	[3]
Earnings Per Share, Basic	$ 4.25		$ 3.82		$ 3.11
Earnings Per Share, Diluted	$ 4.20	[4]	$ 3.79	[4]	$ 3.09	[4]

[1] Amount for 2012 included $8 million related to Series C preferred stock issued in August 2012. Remaining amount for 2012 and amount for 2011 were related to Series A preferred stock, which was redeemed in October 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 awards, contain 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.