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, 2019	$ 24,431	$ 2,962	$ 504	$ 10,132	$ 21,918	$ (876)	$ (10,209)
Beginning balance ( in shares) at Dec. 31, 2019			503,880
Treasury stock, beginning balance (in shares) at Dec. 31, 2019							146,490
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,420				2,420
Other comprehensive income (loss)	1,063					1,063
Preferred stock redeemed	(500)	(491)			(9)
Common stock dividends	(734)				(734)
Preferred stock cash dividend	(152)				(152)
Common stock acquired (in shares)							6,464
Common stock acquired	(500)						$ (500)
Common stock awards exercised (in shares)							(2,233)
Common stock awards exercised	172			72			$ 100
Other (in shares)							2
Other	0			1	(1)		$ 0
Ending balance at Dec. 31, 2020	26,200	2,471	$ 504	10,205	23,442	187	$ (10,609)
Ending balance (in shares) at Dec. 31, 2020			503,880
Treasury stock, ending balance (in shares) at Dec. 31, 2020							150,723
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,693				2,693
Other comprehensive income (loss)	(1,320)					(1,320)
Common stock issued (in shares)							(21,724)
Common stock issued	1,900			516			$ 1,384
Preferred stock redeemed	(500)	(495)			(5)
Common stock dividends	(779)				(779)
Preferred stock cash dividend	(114)				(114)
Common stock acquired (in shares)							11,250
Common stock acquired	(900)						$ (900)
Common stock awards exercised (in shares)							(2,350)
Common stock awards exercised	164			48			$ 116
Other (in shares)							(2)
Other	19			18	1		$ 0
Ending balance at Dec. 31, 2021	27,363	1,976	$ 504	10,787	25,238	(1,133)	$ (10,009)
Ending balance (in shares) at Dec. 31, 2021			503,880
Treasury stock, ending balance (in shares) at Dec. 31, 2021							137,897
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,774				2,774
Other comprehensive income (loss)	(2,578)					(2,578)
Common stock dividends	(871)				(871)
Preferred stock cash dividend	(112)				(112)
Common stock acquired (in shares)							19,524
Common stock acquired	(1,500)						$ (1,500)
Common stock awards exercised (in shares)							(2,565)
Common stock awards exercised	129			(43)			$ 172
Other (in shares)							(1)
Other	(14)			(14)	(1)		$ 1
Ending balance at Dec. 31, 2022	$ 25,191	$ 1,976	$ 504	$ 10,730	$ 27,028	$ (3,711)	$ (11,336)
Ending balance (in shares) at Dec. 31, 2022			503,880
Treasury stock, ending balance (in shares) at Dec. 31, 2022							154,855