Consolidated Statement of Changes In Shareholders' Equity (Unaudited) (USD $) In Millions, except Share data, unless otherwise specified	Total	PREFERRED STOCK	PREFERRED STOCK Series C Preferred Stock	COMMON STOCK	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	TREASURY STOCK
Beginning balance at Dec. 31, 2011	$ 19,398	$ 500		$ 504	$ 9,557	$ 10,176	$ (659)	$ (680)
Beginning balance (shares) at Dec. 31, 2011				503,966,000				16,542,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	917					917
Other comprehensive income	122						122
Cash dividends declared:
Common stock	(233)					(233)
Preferred stock	(14)					(14)
Common stock acquired (shares)								11,098,000
Common stock acquired	(480)							(480)
Common stock awards and options exercised, including related taxes (shares)				(35,000)				(2,534,000)
Common stock awards and options exercised, including related taxes	186				65			121
Other	1				1
Other (shares)								3,000
Ending balance at Jun. 30, 2012	19,897	500		504	9,623	10,846	(537)	(1,039)
Ending balance (shares) at Jun. 30, 2012				503,931,000				25,109,000
Beginning balance at Dec. 31, 2012	20,869	489		504	9,667	11,751	360	(1,902)
Beginning balance (shares) at Dec. 31, 2012				503,900,000				45,238,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,043					1,043
Other comprehensive income	(883)						(883)
Accretion of issuance costs	0		1			(1)
Cash dividends declared:
Common stock	(235)					(235)
Preferred stock	(13)					(13)
Common stock acquired (shares)	15,000,000							15,068,000
Common stock acquired	(920)							(920)
Common stock awards and options exercised, including related taxes (shares)				(9,000)				(4,807,000)
Common stock awards and options exercised, including related taxes	220				46			174
Other (shares)								(3,000)
Ending balance at Jun. 30, 2013	$ 20,081	$ 490		$ 504	$ 9,713	$ 12,545	$ (523)	$ (2,648)
Ending balance (shares) at Jun. 30, 2013				503,891,000				55,496,000