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, 2017	$ 22,270	$ 3,196	$ 504	$ 9,799	$ 18,809		$ (1,009)		$ (9,029)
Beginning balance (shares) at Dec. 31, 2017			503,880						136,230
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	659				659
Other comprehensive income	(65)						(65)
Cash dividends declared:
Common stock dividends	(154)				(154)
Preferred stock cash dividend	(55)				(55)
Common stock acquired	(350)								$ (350)
Common stock acquired (shares)									3,324
Common stock awards exercised	42			(3)					$ 45
Common stock awards vested (shares)									(1,075)
Other	3				3
Other (shares)									(7)
Ending balance at Mar. 31, 2018	22,350	3,196	$ 504	9,796	19,262		(1,074)		$ (9,334)
Ending balance (shares) at Mar. 31, 2018			503,880						138,472
Beginning balance at Dec. 31, 2018	24,737	3,690	$ 504	10,061	20,553		(1,356)		$ (8,715)
Beginning balance (shares) at Dec. 31, 2018			503,880						123,933
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of certain tax effects	(84)				84	[1]	(84)	[1]
Net income	508				508
Other comprehensive income	260						260
Cash dividends declared:
Common stock dividends	(177)				(177)
Preferred stock cash dividend	(55)				(55)
Common stock acquired	(300)								$ (300)
Common stock acquired (shares)									4,230
Common stock awards exercised	71			26					$ 45
Common stock awards vested (shares)									(1,002)
Other	(6)			(5)	(2)				$ 1
Other (shares)									(2)
Ending balance at Mar. 31, 2019	$ 25,038	$ 3,690	$ 504	$ 10,082	$ 20,911		$ (1,180)		$ (8,969)
Ending balance (shares) at Mar. 31, 2019			503,880						127,159

[1] ⁽¹⁾ Represents the reclassification from accumulated other comprehensive income into retained earnings as a result of our adoption of ASU 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income in the first quarter of 2019.