Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Taxes calculated using the estimated annual effective tax rate	$ 229	$ 391	$ 794	$ 1,147
Discrete tax items	(16)	(28)	(63)	(69)
Provision for income taxes	$ 213	$ 363	$ 731	$ 1,078
Effective tax rate	11.00%	14.00%	12.00%	14.00%