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The gains (losses) recognised in profit or loss on the fair value measurement of assets and liabilities. [Refer: At fair value [member]]

No definition available.

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The increase in fair value measurement of assets and liabilities resulting from issues of those assets and liabilities. [Refer: At fair value [member]]

No definition available.

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The increase in the fair value measurement of assets and liabilities resulting from purchases of those assets and liabilities. [Refer: At fair value [member]]

No definition available.

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Reconciliation Of Changes In Fair Value Measurement, Assets (Liabilities)

No definition available.

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The decrease in the fair value measurement of assets and liabilities resulting from sales of those assets and liabilities. [Refer: At fair value [member]]

No definition available.

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The decrease in the fair value measurement of assets and liabilities resulting from settlements of those assets and liabilities. [Refer: At fair value [member]]

No definition available.

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The amount of transfers of assets less liabilities into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

No definition available.

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The amount of transfers of assets less liabilities out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

No definition available.

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The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

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The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]

Name:	ifrs-full_DerivativeFinancialLiabilities
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The fair value of financial assets. [Refer: At fair value [member]; Financial assets]

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Name:	ifrs-full_FinancialAssetsAtFairValue
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The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

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Data Type:	xbrli:monetaryItemType
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The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of assets. [Refer: At fair value [member]; Other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-Note Effective 2027-01-01
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The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of liabilities. [Refer: At fair value [member]; Other comprehensive income]

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The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of assets. [Refer: At fair value [member]]

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The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of liabilities. [Refer: At fair value [member]]

Name:	ifrs-full_GainsLossesRecognisedInProfitOrLossFairValueMeasurementLiabilities
Namespace Prefix:	ifrs-full_
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The increase in the fair value measurement of assets resulting from issues of those assets. [Refer: At fair value [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2025-01-01
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Name:	ifrs-full_IssuesFairValueMeasurementAssets
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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The increase in fair value measurement of liabilities resulting from issues of those liabilities. [Refer: At fair value [member]]

Name:	ifrs-full_IssuesFairValueMeasurementLiabilities
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Balance Type:	credit
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The amount of assets less the amount of liabilities.

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Name:	ifrs-full_NetAssetsLiabilities
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The increase in the fair value measurement of assets resulting from purchases of those assets. [Refer: At fair value [member]]

Name:	ifrs-full_PurchasesFairValueMeasurementAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

The increase in the fair value measurement of liabilities resulting from purchases of those liabilities. [Refer: At fair value [member]]

Name:	ifrs-full_PurchasesFairValueMeasurementLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

Name:	ifrs-full_ReconciliationOfChangesInFairValueMeasurementAssetsAbstract
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- References

No definition available.

Name:	ifrs-full_ReconciliationOfChangesInFairValueMeasurementLiabilitiesAbstract
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The decrease in the fair value measurement of assets resulting from sales. [Refer: At fair value [member]]

Name:	ifrs-full_SalesFairValueMeasurementAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
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The decrease in the fair value measurement of liabilities resulting from sales. [Refer: At fair value [member]]

Name:	ifrs-full_SalesFairValueMeasurementLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
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The decrease in the fair value measurement of assets resulting from settlements. [Refer: At fair value [member]]

Name:	ifrs-full_SettlementsFairValueMeasurementAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
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The decrease in the fair value measurement of liabilities resulting from settlements. [Refer: At fair value [member]]

Name:	ifrs-full_SettlementsFairValueMeasurementLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of transfers of assets into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2025-01-01
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Name:	ifrs-full_TransfersIntoLevel3OfFairValueHierarchyAssets
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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The amount of transfers of liabilities into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

Name:	ifrs-full_TransfersIntoLevel3OfFairValueHierarchyLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of transfers of assets out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

Name:	ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The amount of transfers of liabilities out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]

Name:	ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level3OfFairValueHierarchyMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_MeasurementAxis=ifrs-full_RecurringFairValueMeasurementMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_ClassesOfFinancialLiabilitiesAxis=bcs_DerivativesNettingMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=ifrs-full_InvestmentPropertyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_FinancialAssetsAtFairValueThroughProfitOrLossCategoryTradingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_FinancialAssetsAtFairValueThroughProfitOrLossCategoryOtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_CategoriesOfFinancialLiabilitiesAxis=ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossThatMeetDefinitionOfHeldForTradingCategoryMember
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Data Type:	na
Balance Type:
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Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_AssetsAndLiabilitiesAxis=bcs_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	ifrs-full_CategoriesOfFinancialLiabilitiesAxis=ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionCategoryMember
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