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	4,063					4,063
Other comprehensive income (loss)	(198)				(198)	0
Repurchase of common shares	(2,094)		(2)	(179)		(1,913)
Other changes, primarily employee plans	103			160		(57)
Cash dividends declared preferred							$ (29)	$ (29)
Cash dividends declared common	(787)					(787)
Ending Balance at Jun. 30, 2022	23,235	0	151	11,476	(3,143)	14,751
Beginning Balance at Mar. 31, 2022	22,383	0	151	11,451	(2,973)	13,754
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,964					1,964
Other comprehensive income (loss)	(170)				(170)	0
Repurchase of common shares	(611)			(53)		(558)
Other changes, primarily employee plans	77			78		(1)
Cash dividends declared preferred							(15)	(15)
Cash dividends declared common	(393)					(393)
Ending Balance at Jun. 30, 2022	23,235	0	151	11,476	(3,143)	14,751
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	3,990					3,990
Other comprehensive income (loss)	126				126	0
Repurchase of common shares	(1,312)		(1)	(123)		(1,188)
Other changes, primarily employee plans	112			139		(27)
Cash dividends declared preferred							(29)	(29)
Cash dividends declared common	(895)					(895)
Ending Balance at Jun. 30, 2023	26,703	0	148	11,509	(3,084)	18,130
Beginning Balance at Mar. 31, 2023	25,992	0	149	11,522	(3,106)	17,427
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,174					2,174
Other comprehensive income (loss)	22				22	0
Repurchase of common shares	(1,117)		(1)	(106)		(1,010)
Other changes, primarily employee plans	92			93		(1)
Cash dividends declared preferred							$ (15)	$ (15)
Cash dividends declared common	(445)					(445)
Ending Balance at Jun. 30, 2023	$ 26,703	$ 0	$ 148	$ 11,509	$ (3,084)	$ 18,130