Consolidated Statement of Changes In Shareholders' Equity (USD $) In Millions, except Share data in Thousands, 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				16,542
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,061				2,061
Other comprehensive income (loss)	1,019					1,019
Redemption of preferred stock	(500)	(500)
Preferred stock issued	488	488
Accretion of issuance costs	0	(1)			(1)
Cash dividends declared:
Common stock dividends	(456)				(456)
Preferred stock cash dividend	(29)				(29)
Common stock acquired	(1,440)						(1,440)
Common stock acquired (shares)							33,408
Common stock awards and options exercised, including related taxes	327			110			217
Common stock awards and options exercised, including related taxes (shares)			(66)				(4,693)
Other	1						1
Other (shares)							(19)
Ending balance at Dec. 31, 2012	20,869	489	504	9,667	11,751	360	(1,902)
Ending balance (shares) at Dec. 31, 2012			503,900				45,238
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,136				2,136
Other comprehensive income (loss)	(455)					(455)
Accretion of issuance costs	0	(2)			(2)
Cash dividends declared:
Common stock dividends	(463)				(463)
Preferred stock cash dividend	(26)				(26)
Common stock acquired	(2,040)						(2,040)
Common stock acquired (shares)							31,237
Common stock awards and options exercised, including related taxes	362			113			249
Common stock awards and options exercised, including related taxes (shares)	(2,725)		(17)				(6,709)
Other	(5)			(4)	(1)
Other (shares)							(12)
Ending balance at Dec. 31, 2013	20,378	491	504	9,776	13,395	(95)	(3,693)
Ending balance (shares) at Dec. 31, 2013			503,883				69,754
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,037				2,037
Other comprehensive income (loss)	(412)					(412)
Preferred stock issued	1,470	1,470
Cash dividends declared:
Common stock dividends	(490)				(490)
Preferred stock cash dividend	(61)				(61)
Common stock acquired	(1,650)						(1,650)
Common stock acquired (shares)	23,800						23,749
Common stock awards and options exercised, including related taxes	202			17			185
Common stock awards and options exercised, including related taxes (shares)	(801)		(3)				(4,805)
Other	(1)			(2)	1
Other (shares)							(13)
Ending balance at Dec. 31, 2014	$ 21,473	$ 1,961	$ 504	$ 9,791	$ 14,882	$ (507)	$ (5,158)
Ending balance (shares) at Dec. 31, 2014			503,880				88,685