Income taxes - Income before income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
U.S.	$ 6,445	$ 9,122	$ 7,998
Non-U.S.	973	910	921
Income before income taxes	$ 7,418	$ 10,032	$ 8,919