Employee benefit obligations (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Employee benefit obligations.
Re-measurement of employee benefit obligations	$ 1,000,000	$ 1,000,000	$ 5,000,000	$ 8,000,000
Increase (Decrease) In Defined Benefit Obligation.	4,000,000	2,000,000	(3,000,000)	(7,000,000)
Increase (Decrease) In Asset Valuation.	$ 5,000,000	$ 3,000,000	$ 2,000,000	$ 1,000,000

The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [domain]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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