Name:	ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 24
-IssueDate 2021-01-01
-Paragraph 18
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2021-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2021-03-24

Name:	ifrs-full_OutstandingCommitmentsMadeByEntityRelatedPartyTransactions
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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
Period Type:	duration

The amount of contingent liabilities and other resulting from related party transactions.

No definition available.

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

The derivative financial instruments resulting from related party transactions.

No definition available.

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

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

No definition available.

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

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
Period Type:	duration

The amount of gains or losses on financial assets and liabilities and others attributable to related party transactions.

No definition available.

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

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

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=san_AssociatesAndJointVenturesMember
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Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DepositsCreditInstitutionsMember
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Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DepositsCustomersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=san_DebtInstrumentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
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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
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_LoansAndAdvancesCreditInstitutionsMember
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Data Type:	na
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_LoansAndAdvancesCustomersMember
Namespace Prefix:
Data Type:	na
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_DebtSecuritiesMember
Namespace Prefix:
Data Type:	na
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Name:	ifrs-full_ClassesOfFinancialAssetsAxis=san_OtherFinancialAssetsMember
Namespace Prefix:
Data Type:	na
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Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=san_MembersOfBoardOfDirectorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=srt_ExecutiveVicePresidentMember
Namespace Prefix:
Data Type:	na
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