Income taxes - Income tax expense (benefit) components (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income tax expense:
U.S. federal	$ 18,481	$ 20,764	$ (10,316)
U.S. state	767	763	762
Foreign	1,567	1,492	1,052
Total income taxes	20,815	23,019	(8,502)
Income tax expense:
Current	30,464	7,642	4,815
Deferred	(9,649)	15,377	(13,317)
Total income taxes	$ 20,815	$ 23,019	$ (8,502)