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	5,942					5,942
Other comprehensive income (loss)	(432)				(432)	0
Repurchase of common shares	(2,694)		(3)	(240)		(2,451)
Other changes, primarily employee plans	168			227		(59)
Cash dividends declared preferred							$ (43)	$ (43)
Cash dividends declared common	(1,178)					(1,178)
Ending Balance at Sep. 30, 2022	23,940	0	150	11,482	(3,377)	15,685
Beginning Balance at Jun. 30, 2022	23,235	0	151	11,476	(3,143)	14,751
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,879					1,879
Other comprehensive income (loss)	(234)				(234)	0
Repurchase of common shares	(600)		(1)	(61)		(538)
Other changes, primarily employee plans	65			67		(2)
Cash dividends declared preferred							(14)	(14)
Cash dividends declared common	(391)					(391)
Ending Balance at Sep. 30, 2022	23,940	0	150	11,482	(3,377)	15,685
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	6,441					6,441
Other comprehensive income (loss)	34				34	0
Repurchase of common shares	(2,611)		(3)	(246)		(2,362)
Other changes, primarily employee plans	126			154		(28)
Cash dividends declared preferred							(43)	(43)
Cash dividends declared common	(1,334)					(1,334)
Ending Balance at Sep. 30, 2023	27,324	0	146	11,401	(3,176)	18,953
Beginning Balance at Jun. 30, 2023	26,703	0	148	11,509	(3,084)	18,130
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,451					2,451
Other comprehensive income (loss)	(92)				(92)	0
Repurchase of common shares	(1,299)		(2)	(123)		(1,174)
Other changes, primarily employee plans	14			15		(1)
Cash dividends declared preferred							$ (14)	$ (14)
Cash dividends declared common	(439)					(439)
Ending Balance at Sep. 30, 2023	$ 27,324	$ 0	$ 146	$ 11,401	$ (3,176)	$ 18,953