Provisions for employee benefits - Actuarial assumptions used in the measurement of the liabilities (Details)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Other benefit plans
Disclosure Of Benefit Plans [Line Items]
Rate of price inflation	2.00%	2.00%
Other benefit plans \| Minimum
Disclosure Of Benefit Plans [Line Items]
Discount rate	2.40%	2.80%
Other benefit plans \| Maximum
Disclosure Of Benefit Plans [Line Items]
Discount rate	3.20%	3.10%
Italian defined benefit plans
Disclosure Of Benefit Plans [Line Items]
Discount rate	3.20%	3.10%
Rate of compensation increase	3.00%	3.00%
Rate of price inflation	2.00%	2.00%
Foreign defined benefit plan \| Minimum
Disclosure Of Benefit Plans [Line Items]
Discount rate	1.30%	1.10%
Rate of compensation increase	2.00%	2.00%
Rate of price inflation	1.00%	1.00%
Life expectations on retirement at age 65	1414 years	1414 years
Foreign defined benefit plan \| Maximum
Disclosure Of Benefit Plans [Line Items]
Discount rate	20.50%	26.10%
Rate of compensation increase	19.70%	15.00%
Rate of price inflation	14.00%	14.00%
Life expectations on retirement at age 65	2424 years	2424 years
FISDE
Disclosure Of Benefit Plans [Line Items]
Discount rate	3.20%	3.10%
Rate of price inflation	2.00%	2.00%
Life expectations on retirement at age 65	24 years	24 years

No definition available.

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- Definition

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]]

+ References

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

+ Details

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- Definition

The expected rate of inflation that is 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

+ Details

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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

+ Details

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- Definition

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]]

+ References

+ Details

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