Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Taxes calculated using the estimated annual effective tax rate	$ 395	$ 322	$ 756	$ 597
Discrete tax items	(5)	(11)	(41)	(100)
Provision for income taxes	$ 390	$ 311	$ 715	$ 497
Effective tax rate	15.00%	14.00%	14.00%	12.00%