Intangible assets - Narrative (Details) € in Millions	6 Months Ended
Jun. 30, 2025 EUR (€)
Disclosure of information for cash-generating units [line items]
Increase (decrease) in goodwill	€ (1,478)
Impairment loss recognised in profit or loss, goodwill	0
Goodwill \| Santander Bank Polska
Disclosure of information for cash-generating units [line items]
Increase (decrease) through transfers, intangible assets and goodwill	€ (1,178)

The increase (decrease) in goodwill. [Refer: Goodwill]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2024-01-01
-Paragraph B67
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2024-en-r&anchor=para_B67_d&doctype=Appendix&subtype=B
-URIDate 2024-03-27

+ Details

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- Definition

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.

+ Details

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- Definition

The amount of impairment loss recognised in profit or loss for goodwill. [Refer: Impairment loss recognised in profit or loss; Goodwill]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2024-01-01
-Paragraph B67
-Subparagraph d
-Clause v
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2024-en-r&anchor=para_B67_d_v&doctype=Appendix&subtype=B
-URIDate 2024-03-27

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- Definition

The increase (decrease) in intangible assets and goodwill resulting from transfers. [Refer: Intangible assets and goodwill]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 38
-IssueDate 2024-01-01
-Paragraph 118
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2024-en-r&anchor=para_118_e&doctype=Standard
-URIDate 2024-03-27

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