Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 2,842	$ 3,662	$ 2,697
Other comprehensive income (loss):
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	(9,276)	(2,115)	2,331
Changes in net unrealized gains (losses) on investment securities having credit losses recognized in the consolidated statement of income	(4)	0	(9)
Net changes in benefit plan assets and obligations	(87)	455	18
Net changes in unrealized foreign currency translation	(273)	(11)	12
Other comprehensive income (loss) before income taxes	(9,640)	(1,671)	2,352
Income tax expense (benefit)	(2,002)	(362)	490
Other comprehensive income (loss), net of taxes	(7,638)	(1,309)	1,862
Comprehensive income (loss)	$ (4,796)	$ 2,353	$ 4,559