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The amount of outstanding commitments made by the entity in related party transactions. [Refer: Total for all related parties [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2025-01-01
-Paragraph 18
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 230
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230_b&doctype=Standard
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 230
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230_b&doctype=Standard
-URIDate 2025-03-27

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The amount of assets attributable to related party transactions.

No definition available.

Name:	san_AssetsRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The amount of commission expense attributable to related party transactions.

No definition available.

Name:	san_CommissionExpenseRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of commission income attributable to related party transactions.

No definition available.

Name:	san_CommissionIncomeRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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The amount of contingent liabilities and other resulting from related party transactions.

No definition available.

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Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
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The derivative financial instruments resulting from related party transactions.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

The amount of finance costs incurred by the entity in related party transactions.

No definition available.

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Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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The amount of finance income recognized by the entity in related party transactions.

No definition available.

Name:	san_FinanceIncomeRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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The amount of gains or losses on financial assets and liabilities and others attributable to related party transactions.

No definition available.

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Data Type:	xbrli:monetaryItemType
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The amount of liabilities attributable to related party transactions.

No definition available.

Name:	san_LiabilitiesRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of related-party transactions classified as other.

No definition available.

Name:	san_OtherRelatedPartyTransactions
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The profit (loss) before tax expense or income, attributable to related party transactions.

No definition available.

Name:	san_ProfitLossRelatedParty
Namespace Prefix:	san_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DepositsCreditInstitutionsMember
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Data Type:	na
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Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DepositsCustomersMember
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Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DebtInstrumentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_OtherFinancialLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_CashCashBalanceAtCentralBanksAndOtherDepositsOnDemandMember
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Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_LoansAndAdvancesCreditInstitutionsMember
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Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_LoansAndAdvancesCustomersMember
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_DebtSecuritiesMember
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Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=srt_DirectorMember
Namespace Prefix:
Data Type:	na
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Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=san_SeniorManagementMember
Namespace Prefix:
Data Type:	na
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