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, 2022	$ 25,191	$ 1,976	$ 504	$ 10,730	$ 27,028	$ (3,711)	$ (11,336)
Beginning balance (shares) at Dec. 31, 2022			503,880,000
Treasury stock, beginning balance (in shares) at Dec. 31, 2022							154,855,000
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 dividends	(23)				(23)
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
Treasury stock, ending balance (in shares) at Mar. 31, 2023							167,418,000
Beginning balance at Dec. 31, 2023	$ 23,799	$ 1,976	$ 504	10,741	27,957	(2,354)	$ (15,025)
Beginning balance (shares) at Dec. 31, 2023			503,880,000
Treasury stock, beginning balance (in shares) at Dec. 31, 2023	201,935,599						201,936,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 463				463
Other comprehensive income (loss)	(15)					(15)
Preferred stock issued (shares)		1,481,000,000
Preferred stock issued	1,481
Preferred stock redeemed	(1,000)	$ (989)			(11)
Cash dividends declared:
Common stock dividends	(208)				(208)
Preferred stock cash dividends	(34)				(34)
Common stock acquired	(100)						$ (100)
Common stock acquired (shares)							1,365,000
Common stock awards exercised	49			(17)			$ 66
Common stock awards exercised (in shares)							(926,000)
Other	(2)				(1)		$ (1)
Ending balance at Mar. 31, 2024	$ 24,433	$ 2,468	$ 504	$ 10,724	$ 28,166	$ (2,369)	$ (15,060)
Ending balance (shares) at Mar. 31, 2024			503,880,000
Treasury stock, ending balance (in shares) at Mar. 31, 2024	202,375,172						202,375,000