Provisions - Schedule of funding status of the defined benefit obligations (Details) - Spain - EUR (€) € in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Post-employment plans
Disclosure of net defined benefit liability (asset) [line items]
To current employees	€ 34	€ 49	€ 51
Vested obligations to retired employees	1,610	1,850	1,936
To pre-retirees employees		0	0
Long-service bonuses and other benefits		0	0
Present value of the obligations	1,644	1,899	1,987
Less - Fair value of plan assets	1,058	1,234	1,235
Provisions - Provisions for pensions	586	665	752
Internal provisions for pensions	535	593	677
Net pension assets	(13)	(6)	(14)
Insurance contracts linked to pensions (note 14)	67	81	93	€ 104
Unrecognised net assets for pensions	(3)	(3)	(4)
Other similar obligations
Disclosure of net defined benefit liability (asset) [line items]
To current employees	0	0	0
Vested obligations to retired employees	0	0	0
To pre-retirees employees	919	844	812
Long-service bonuses and other benefits	11	13	12
Present value of the obligations	930	857	824
Less - Fair value of plan assets	3	5	7
Provisions - Provisions for pensions	927	852	817
Internal provisions for pensions	927	852	817
Net pension assets	0	0	0
Insurance contracts linked to pensions (note 14)	0	0	0	€ 0
Unrecognised net assets for pensions	€ 0	€ 0	€ 0

The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2025-01-01
-Paragraph 57
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_57_a&doctype=Standard
-URIDate 2025-03-27

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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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The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]

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The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]]

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The present value, without deducting any plan assets, of expected future payments required to settle the obligation of long-service bonuses and other benefits resulting from employee service in the current and prior periods.

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The present value, without deducting any plan assets, of expected future payments required to settle the obligation to current employees resulting from employee service in the current and prior periods.

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The present value, without deducting any plan assets, of expected future payments required to settle the obligation to pre-retirees resulting from employee service in the current and prior periods.

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The present value, without deducting any plan assets, of expected future payments required to settle the vested obligations to retired employees resulting from employee service in the current and prior periods.

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Insurance contracts linked to pensions

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Internal provisions for pensions.

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Net Pension Assets

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Unrecognized net assets for pensions.

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