Income taxes (Details) $ in Millions	Sep. 30, 2025 USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 104
Unrecognized tax benefits that would impact effective tax rate if recognized	104
Accrued interest related to the gross unrecognized tax benefits excluded from the unrecognized tax benefits	30
Accrued penalties related to the gross unrecognized tax benefits excluded from the unrecognized tax benefits	2
Amount of gross unrecognized tax benefits could be reduced by as a result of the revaluation of existing uncertain tax positions	$ 60