Income taxes - Income tax expense (benefit) components (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income tax expense:
U.S. Federal	$ 20,764	$ (10,316)	$ 20,384
U.S. State	763	762	(527)
Foreign	1,492	1,052	1,055
Total income taxes	23,019	(8,502)	20,912
Income tax expense:
Current	7,642	4,815	5,326
Deferred	15,377	(13,317)	15,586
Total income taxes	$ 23,019	$ (8,502)	$ 20,912