Income taxes - Schedule of Valuation Allowance - (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Valuation Allowance [Roll Forward]
Balance as of January 1	$ 1,059	$ 914	$ 737
Acquisitions	(6)	12	0
Provision for income taxes	162	188	151
Foreign currency and other	121	(55)	26
Balance as of December 31	$ 1,336	$ 1,059	$ 914