Consolidated Statement of Changes in Shareholders' Equity - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2020	$ 26,200	$ 2,471	$ 504	$ 10,205	$ 23,442	$ 187	$ (10,609)
Beginning balance ( in shares) at Dec. 31, 2020			503,880,000
Treasury stock, beginning balance (in shares) at Dec. 31, 2020							150,723,000
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)							(21,724,000)
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)							11,250,000
Common stock acquired	(900)						$ (900)
Common stock awards exercised (in shares)							(2,350,000)
Common stock awards exercised	164			48			$ 116
Other (in shares)							(2,000)
Other	19			18	1
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			503,880,000
Treasury stock, ending balance (in shares) at Dec. 31, 2021							137,897,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared (in USD per share)	$ 2.18
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)							19,524,000
Common stock acquired	(1,500)						$ (1,500)
Common stock awards exercised (in shares)							(2,565,000)
Common stock awards exercised	129			(43)			$ 172
Other (in shares)							(1,000)
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			503,880,000
Treasury stock, ending balance (in shares) at Dec. 31, 2022	154,855,475						154,855,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared (in USD per share)	$ 2.40
Net income	$ 1,944				1,944
Other comprehensive income (loss)	1,357					1,357
Common stock dividends	(837)				(837)
Preferred stock cash dividend	(122)				(122)
Common stock acquired (in shares)							49,212,000
Common stock acquired	(3,837)						$ (3,837)
Common stock awards exercised (in shares)							(2,133,000)
Common stock awards exercised	159			11			$ 148
Other (in shares)							2,000
Other	(56)				(56)
Ending balance at Dec. 31, 2023	$ 23,799	$ 1,976	$ 504	$ 10,741	$ 27,957	$ (2,354)	$ (15,025)
Ending balance (in shares) at Dec. 31, 2023			503,880,000
Treasury stock, ending balance (in shares) at Dec. 31, 2023	201,935,599						201,936,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividends declared (in USD per share)	$ 2.64