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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock (shares)							137,897,000
Beginning balance at Dec. 31, 2021	$ 27,363	$ 1,976	$ 504	$ 10,787	$ 25,238	$ (1,133)	$ (10,009)
Beginning balance (shares) at Dec. 31, 2021			503,880,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	604				604
Other comprehensive income (loss)	(1,565)					(1,565)
Cash dividends declared:
Common stock dividends	(209)				(209)
Preferred stock cash dividend	(20)				(20)
Common stock awards exercised	66			(11)			$ 77
Common stock awards exercised (in shares)							(1,132,000)
Other	(15)			(14)	(1)
Ending balance at Mar. 31, 2022	$ 26,224	1,976	$ 504	10,762	25,612	(2,698)	$ (9,932)
Ending balance (shares) at Mar. 31, 2022			503,880,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock (shares)							136,765,000
Treasury stock (shares)	154,855,475						154,855,000
Beginning balance at Dec. 31, 2022	$ 25,191	1,976	$ 504	10,730	27,028	(3,711)	$ (11,336)
Beginning balance (shares) at Dec. 31, 2022			503,880,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	549				549
Other comprehensive income (loss)	439					439
Cash dividends declared:
Common stock dividends	(212)				(212)
Preferred stock cash dividend	(23)				(23)
Common stock acquired	(1,262)						$ (1,262)
Common stock acquired (shares)							13,647,000
Common stock awards exercised	69			(6)			$ 75
Common stock awards exercised (in shares)							(1,085,000)
Other	(1)						$ (1)
Other (shares)							1,000
Ending balance at Mar. 31, 2023	$ 24,750	$ 1,976	$ 504	$ 10,724	$ 27,342	$ (3,272)	$ (12,524)
Ending balance (shares) at Mar. 31, 2023			503,880,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock (shares)	167,418,570						167,418,000