Employee benefits - Disclosure of Actuarial Assumptions for Defined Benefit Plans (Details) - Allowance for retirement defined benefit	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of defined benefit plans [line items]
Discount rate (iBoxx Corporate AA) for retirement	3.85%	3.20%	3.20%
Annual rate of increase in wages		2.50%	2.50%
Annual mobility rate		5.70%	5.20%
Rate of contributions		49.29%	48.01%
Rate of wages costs		22.62%	24.32%
16-24 years	20.00%	20.00%	15.00%
25-29 years	15.00%	16.00%	14.00%
30-34 years	12.00%	12.00%	10.00%
35-39 years	9.00%	8.00%	6.00%
40-44 years	4.00%	4.00%	4.00%
45-49 years	2.00%	2.00%	2.00%
+50 years
Executives \| Employees born before 1 January 1968
Disclosure of defined benefit plans [line items]
Age at retirement	64 years	64 years	64 years
Executives \| Employees born after 1 January 1968
Disclosure of defined benefit plans [line items]
Age at retirement	65 years	65 years	65 years
Non-executives \| Employees born before 1 January 1968
Disclosure of defined benefit plans [line items]
Age at retirement	62 years	62 years	62 years
Non-executives \| Employees born after 1 January 1968
Disclosure of defined benefit plans [line items]
Age at retirement	64 years	64 years	64 years

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2025-01-01
-Paragraph 144
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_144&doctype=Standard
-URIDate 2025-03-27

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- Definition

The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [domain]; Defined benefit obligation, at present value; Actuarial assumptions [domain]]

+ References

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- Definition

The retirement age 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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Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

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The amount of annual mobility rate of actuarial assumptions.

+ References

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- Definition

The annual turnover rate for 16-24 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

+ References

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- Definition

The annual turnover rate for 25-29 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The annual turnover rate for 30-34 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The annual turnover rate for 35-39 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The annual turnover rate for 40-44 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The annual turnover rate for 45-49 years old employees used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The annual turnover rate for employees over 50 years old used as a significant actuarial assumption to determine the present value of a defined benefit obligation.

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- Definition

The amount of rate of wages costs in actuarial assumptions.

+ References

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- Definition

The percent of rate of contributions for actuarial assumptions.

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