Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Taxes calculated using the estimated annual effective tax rate	$ 289	$ 395	$ 565	$ 756
Discrete tax items	(9)	(5)	(47)	(41)
Provision for income taxes	$ 280	$ 390	$ 518	$ 715
Effective tax rate	14.00%	15.00%	13.00%	14.00%