Name:	ifrs-full_DisclosureOfBusinessCombinationsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
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Period Type:	duration

The number of instruments or interests issued or issuable at acquisition date for equity interests of the acquirer transferred as consideration in a business combination.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 3
-IssueDate 2021-01-01
-Paragraph B64
-Subparagraph f
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2021-en-r&anchor=para_B64_f_iv&doctype=Appendix&subtype=B
-URIDate 2021-03-24

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

Business Combination, Number Of American Depositary Shares Issuable, Per Acquiree American Depositary Share

No definition available.

Name:	san_BusinessCombinationNumberOfAmericanDepositarySharesIssuablePerAcquireeAmericanDepositaryShare
Namespace Prefix:	san_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Business Combination, Number Of New Shares Issuable, Per Acquiree Share

No definition available.

Name:	san_BusinessCombinationNumberOfNewSharesIssuablePerAcquireeShare
Namespace Prefix:	san_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Increase (Decrease) In Capital Recognised In Business Combination

No definition available.

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

Increase (Decrease) In Issue Premium Recognised In Business Combination

No definition available.

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

Increase (Decrease) In Noncontrolling Interests Recognised In Business Combination

No definition available.

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

Increase (Decrease) In Reserves Recognised In Business Combination

No definition available.

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

The percentage of a shareholder's ownership interest in the entity.

No definition available.

Name:	san_PercentageOfOwnershipInterestInEntity
Namespace Prefix:	san_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The proportion of ownership interests not held by the entity.

No definition available.

Name:	san_ProportionOfOwnershipInterestsNotHeldByEntity
Namespace Prefix:	san_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

The proportion of share capital contributed by the entity.

No definition available.