Income taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Taxes calculated using the estimated annual effective tax rate	$ 249	$ 227	$ 614	$ 573
Discrete tax items	(29)	(35)	(114)	(73)
Provision for income taxes	$ 220	$ 192	$ 500	$ 500
Effective tax rate	14.00%	12.00%	12.00%	12.00%