Consolidated Statement of Changes In Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	PREFERRED STOCK	COMMON STOCK	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	TREASURY STOCK
Beginning balance at Dec. 31, 2013	$ 20,378	$ 491	$ 504	$ 9,776	$ 13,395	$ (95)	$ (3,693)
Beginning balance (shares) at Dec. 31, 2013			503,883				69,754
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,545				1,545
Other comprehensive income (loss)	(12)					(12)
Preferred stock issued	742	742
Cash dividends declared:
Common stock dividends	(366)				(366)
Preferred stock cash dividend	(43)				$ (43)
Common stock acquired	(1,240)						$ (1,240)
Common stock acquired (shares)							18,187
Common stock awards and options exercised, including related taxes	152			4			$ 148
Common stock awards and options exercised, including related taxes (shares)			(3)				(3,984)
Other	0
Other (shares)							(8)
Ending balance (shares) at Sep. 30, 2014			503,880				83,949
Ending balance at Sep. 30, 2014	21,156	1,233	$ 504	9,780	$ 14,531	(107)	$ (4,785)
Beginning balance at Dec. 31, 2014	21,473	1,961	$ 504	9,791	14,882	(507)	$ (5,158)
Beginning balance (shares) at Dec. 31, 2014			503,880				88,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,416
Other comprehensive income (loss)	(594)					(594)
Preferred stock issued	742	742
Cash dividends declared:
Common stock dividends	(401)				(401)
Preferred stock cash dividend	(101)				(101)
Common stock acquired	(1,170)						$ (1,170)
Common stock acquired (shares)							15,552
Common stock awards and options exercised, including related taxes	140			(45)			$ 185
Common stock awards and options exercised, including related taxes (shares)							(4,148)
Other	(5)			(4)	(1)
Other (shares)							(2)
Ending balance (shares) at Sep. 30, 2015			503,880				100,087
Ending balance at Sep. 30, 2015	$ 21,500	$ 2,703	$ 504	$ 9,742	$ 15,795	$ (1,101)	$ (6,143)