Consolidated Statement of Changes In Shareholders' Equity (Unaudited) (USD $) In Millions, except Share data, unless otherwise specified	Total	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	1,591				1,591
Other comprehensive income	845					845
Commitment to redeem preferred stock	(500)	(500)
Preferred stock issued	488	488
Cash dividends declared:
Common stock	(346)				(346)
Preferred stock	(29)				(29)
Common stock acquired (shares)							22,496,000
Common stock acquired	(960)						(960)
Common stock awards and options exercised, including related taxes (shares)			(48,000)				(3,938,000)
Common stock awards and options exercised, including related taxes	260			75			185
Other	2			2
Other (shares)							(9,000)
Ending balance at Sep. 30, 2012	20,749	488	504	9,634	11,392	186	(1,455)
Ending balance (shares) at Sep. 30, 2012			503,918,000				35,091,000
Beginning balance at Jun. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	674
Cash dividends declared:
Common stock					(113)
Ending balance at Sep. 30, 2012	20,749				11,392
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	1,583				1,583
Other comprehensive income	(474)					(474)
Accretion of issuance costs	0	1			(1)
Cash dividends declared:
Common stock	(350)				(350)
Preferred stock	(20)				(20)
Common stock acquired (shares)	23,200,000						23,235,000
Common stock acquired	(1,480)						(1,480)
Common stock awards and options exercised, including related taxes (shares)			(15,000)				(5,874,000)
Common stock awards and options exercised, including related taxes	302			86			216
Other (shares)							(12,000)
Ending balance at Sep. 30, 2013	20,430	490	504	9,753	12,963	(114)	(3,166)
Ending balance (shares) at Sep. 30, 2013			503,885,000				62,587,000
Beginning balance at Jun. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	540
Cash dividends declared:
Common stock					(115)
Ending balance at Sep. 30, 2013	$ 20,430				$ 12,963