Post-employment benefits for associates - Sensitivity analysis (Details) $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($)
Discount rate
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.25%
Percentage of reasonably possible decrease in actuarial assumption	0.25%
Increase (decrease) in defined benefit obligation due to increase in actuarial assumption	$ (23)
Increase (decrease) in defined benefit obligation due to decrease in actuarial assumption	$ 25
Life expectancy
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Actuarial assumption of life expectancy after retirement	1 year
Increase (decrease) in defined benefit obligation due to increase in actuarial assumption	$ 12
Rate of pension increase
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.25%
Percentage of reasonably possible decrease in actuarial assumption	0.25%
Increase (decrease) in defined benefit obligation due to increase in actuarial assumption	$ 8
Increase (decrease) in defined benefit obligation due to decrease in actuarial assumption	$ (4)
Interest on savings account
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.25%
Percentage of reasonably possible decrease in actuarial assumption	0.25%
Increase (decrease) in defined benefit obligation due to increase in actuarial assumption	$ 3
Increase (decrease) in defined benefit obligation due to decrease in actuarial assumption	$ (3)
Rate of salary increase
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.25%
Percentage of reasonably possible decrease in actuarial assumption	0.25%
Increase (decrease) in defined benefit obligation due to increase in actuarial assumption	$ 3
Increase (decrease) in defined benefit obligation due to decrease in actuarial assumption	$ (3)

The life expectancy after retirement used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [domain]]

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The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]]

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]]

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The reasonably possible percentage of the decrease in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [domain]]

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The reasonably possible percentage of the increase in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [domain]]

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