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	Cumulative Effect, Period Of Adoption, Adjustment
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	[1]						84		(84)
Net income		508					508
Other comprehensive income (loss)		260							260
Cash dividends declared:
Common stock dividends		(177)					(177)
Preferred stock cash dividend		(55)					(55)
Common stock acquired (shares)										4,230
Common stock acquired		(300)								$ (300)
Common stock awards exercised		71				26				$ 45
Common stock awards exercised (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
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)
Net income		1,095
Other comprehensive income (loss)		566
Cash dividends declared:
Common stock dividends		(352)
Preferred stock cash dividend		(105)
Ending balance at Jun. 30, 2019		25,454		3,690	$ 504	10,109	21,274		(874)	$ (9,249)
Ending balance (shares) at Jun. 30, 2019					503,880					131,307
Beginning balance at Mar. 31, 2019		25,038		3,690	$ 504	10,082	20,911		(1,180)	$ (8,969)
Beginning balance (shares) at Mar. 31, 2019					503,880					127,159
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		587					587
Other comprehensive income (loss)		306							306
Cash dividends declared:
Common stock dividends		(175)					(175)
Preferred stock cash dividend		(50)					(50)
Common stock acquired (shares)										4,598
Common stock acquired		(300)								$ (300)
Common stock awards exercised		47				27				$ 20
Common stock awards exercised (shares)										(452)
Other		1					1			$ 0
Other (shares)										2
Ending balance at Jun. 30, 2019		25,454		3,690	$ 504	10,109	21,274		(874)	$ (9,249)
Ending balance (shares) at Jun. 30, 2019					503,880					131,307
Cash dividends declared:
Decrease in retained earnings		24,431
Beginning balance at Dec. 31, 2019		24,431		2,962	$ 504	10,132	21,918		(876)	$ (10,209)
Beginning balance (shares) at Dec. 31, 2019					503,880					146,490
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		634					634
Other comprehensive income (loss)		(44)							(44)
Preferred stock redeemed		(500)		(491)			(9)
Cash dividends declared:
Common stock dividends		(183)					(183)
Preferred stock cash dividend		(44)					(44)
Common stock acquired (shares)										6,464
Common stock acquired		(500)								$ (500)
Common stock awards exercised		68				23				$ 45
Common stock awards exercised (shares)										(1,017)
Other	[2]	(1)					(1)
Other (shares)	[2]									(1)
Ending balance at Mar. 31, 2020		23,861		2,471	$ 504	10,155	22,315		(920)	$ (10,664)
Ending balance (shares) at Mar. 31, 2020					503,880					151,936
Beginning balance at Dec. 31, 2019		24,431		2,962	$ 504	10,132	21,918		(876)	$ (10,209)
Beginning balance (shares) at Dec. 31, 2019					503,880					146,490
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		1,328
Other comprehensive income (loss)		446
Cash dividends declared:
Common stock dividends		(366)
Preferred stock cash dividend		(76)
Ending balance at Jun. 30, 2020		24,873		2,471	$ 504	10,179	22,794		(430)	$ (10,645)
Ending balance (shares) at Jun. 30, 2020					503,880					151,496
Cash dividends declared:
Decrease in retained earnings											$ (3)
Beginning balance at Mar. 31, 2020		23,861		2,471	$ 504	10,155	22,315		(920)	$ (10,664)
Beginning balance (shares) at Mar. 31, 2020					503,880					151,936
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		694					694
Other comprehensive income (loss)		490							490
Cash dividends declared:
Common stock dividends		(183)					(183)
Preferred stock cash dividend		(32)					(32)
Common stock awards exercised		44				24				$ 20
Common stock awards exercised (shares)										(443)
Other		(1)	[2]				0	[2]		$ (1)
Other (shares)	[2]									3
Ending balance at Jun. 30, 2020		24,873		$ 2,471	$ 504	$ 10,179	$ 22,794		$ (430)	$ (10,645)
Ending balance (shares) at Jun. 30, 2020					503,880					151,496
Cash dividends declared:
Decrease in retained earnings		$ 24,873

[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.

[2] Includes the impact of transitioning to ASC 326 consisting of a decrease in retained earnings of $3 million in the first quarter of 2020.