Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Preferred Shares	Common Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Series D Preferred Stock	Series D Preferred Stock Retained Earnings
Beginning Balance at Dec. 31, 2021	$ 22,177	$ 0	$ 153	$ 11,495	$ (2,945)	$ 13,474
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,099					2,099
Other comprehensive income (loss)	(28)				(28)	0
Repurchase of common shares	(1,483)		(2)	(126)		(1,355)
Other changes, primarily employee plans	26			82		(56)
Cash dividends declared preferred							$ (14)	$ (14)
Cash dividends declared common	(394)					(394)
Ending Balance at Mar. 31, 2022	22,383	0	151	11,451	(2,973)	13,754
Beginning Balance at Dec. 31, 2022	24,711	0	149	11,493	(3,210)	16,279
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,816					1,816
Other comprehensive income (loss)	104				104	0
Repurchase of common shares	(195)		0	(17)		(178)
Other changes, primarily employee plans	20			46		(26)
Cash dividends declared preferred							$ (14)	$ (14)
Cash dividends declared common	(450)					(450)
Ending Balance at Mar. 31, 2023	$ 25,992	$ 0	$ 149	$ 11,522	$ (3,106)	$ 17,427