Consolidated Statement of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 454	$ 662	$ 2,023	$ 2,329
Other comprehensive income (loss)
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	(3,204)	(686)	(11,078)	(1,749)
Changes in net unrealized gains (losses) on investment securities having credit losses recognized in the consolidated statement of income	0	0	(3)	0
Net changes in benefit plan assets and obligations	12	26	34	77
Net changes in unrealized foreign currency translation	(251)	(91)	(423)	(25)
Other comprehensive loss before income taxes	(3,443)	(751)	(11,470)	(1,697)
Income tax benefit	(690)	(148)	(2,369)	(361)
Other comprehensive loss, net of taxes	(2,753)	(603)	(9,101)	(1,336)
Comprehensive income (loss)	$ (2,299)	$ 59	$ (7,078)	$ 993