Consolidated Statement of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 975	$ 1,018
Other comprehensive income (loss):
Changes in net unrealized gains (losses) on investment securities having no credit losses recognized in the consolidated statement of income	1,308	(4,829)
Changes in net unrealized gains (losses) on investment securities having credit losses recognized in the consolidated statement of income	0	(1)
Net changes in benefit plan assets and obligations	(3)	11
Net changes in unrealized foreign currency translation	37	2
Other comprehensive income (loss) before income taxes	1,342	(4,817)
Income tax expense (benefit)	283	(1,022)
Other comprehensive income (loss), net of taxes	1,059	(3,795)
Comprehensive income (loss)	$ 2,034	$ (2,777)