Provisions - Schedule of changes in fair value of plan assets, United Kingdom (Details) - United Kingdom - Plan assets - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of net defined benefit liability (asset) [line items]
Fair value of plan assets at beginning of year	€ 9,400	€ 10,208	€ 10,152
Net incorporation of companies into the Group	0	0	(41)
Expected return on plan assets	496	478	498
Benefits paid	(469)	(465)	(434)
Contributions	203	182	225
Actuarial gains/(losses)	(421)	(1,440)	(406)
Exchange differences and other items	(469)	437	214
Fair value of plan assets at end of year	€ 8,740	€ 9,400	€ 10,208

The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan. [Refer: Net defined benefit liability (asset); Defined benefit plans [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.

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No definition available.

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The increase (decrease) in the net defined benefit liability (asset) resulting from business combinations and disposals. [Refer: Total for all business combinations [member]; Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)]

+ References

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- Definition

The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [domain]]

+ References

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The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]

+ References

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The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) that result in remeasurements of the net defined benefit liability (asset).

+ References

No definition available.

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Return On Plan Assets Net Defined Benefit Liability Asset Including Interest

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