The amount of litigation settlements approved or agreed upon.

No definition available.

Name:	bcs_LitigationSettlementsApprovedValue
Namespace Prefix:	bcs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The monetary value of the award the plaintiff seeks in the legal matter, in addition to any interest, costs, and punitive damages.

+ References

No definition available.

+ Details

Name:	bcs_LossContingencyDamagesSoughtClaimedAmountsValue
Namespace Prefix:	bcs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of Banks Claims Against

+ References

No definition available.

+ Details

Name:	bcs_NumberOfBanksClaimsAgainst
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Initial Lawsuit Amended

+ References

No definition available.

+ Details

Name:	bcs_NumberOfInitialLawsuitsAmended
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Lawsuits Consolidated Into A Separate Lawsuit

+ References

No definition available.

+ Details

Name:	bcs_NumberOfLawsuitsConsolidatedIntoASeparateLawsuit
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Lawsuits Dismissed

+ References

No definition available.

+ Details

Name:	bcs_NumberOfLawsuitsDismissed
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Lawsuits Subject To Appeal

+ References

No definition available.

+ Details

Name:	bcs_NumberOfLawsuitsSubjectToAppeal
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of lawsuits with damages sought specified.

+ References

No definition available.

+ Details

Name:	bcs_NumberOfLawsuitsWithSpecifiedDamagesSought
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Legal Challenges

+ References

No definition available.

+ Details

Name:	bcs_NumberOfLegalChallenges
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Overseas Subsidiaries Denied VAT Grouping by HMRC

+ References

No definition available.

+ Details

Name:	bcs_NumberOfOverseasSubsidiariesDeniedVATGroupingByHMRC
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Plaintiffs

+ References

No definition available.

+ Details

Name:	bcs_NumberOfPlaintiffs
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Separate Lawsuits

+ References

No definition available.

+ Details

Name:	bcs_NumberOfSeparateLawsuits
Namespace Prefix:	bcs_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Provisions, Annual Compensatory Interest

+ References

No definition available.

+ Details

Name:	bcs_ProvisionsAnnualCompensatoryInterest
Namespace Prefix:	bcs_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) in other provisions. [Refer: Other provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 37
-IssueDate 2025-01-01
-Paragraph 84
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84&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 257
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257&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 257
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257&doctype=Standard
-URIDate 2025-03-27

+ Details

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

- 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

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

- Definition

The amount of liabilities of uncertain timing or amount, including provisions for employee benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 54
-Subparagraph l
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_l&doctype=Standard
-URIDate 2025-03-27

+ Details

Name:	ifrs-full_Provisions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=bcs_MotorFinanceCommissionArrangementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_CivilActionsInRespectOfUSDLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_USResidentialAndCommercialMortgageRelatedActivityAndLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=bcs_OriginatedAndSoldToThirdPartiesByAcquiredSubsidiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=bcs_RmbsRepurchaseRequestsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_CivilActionsInRespectOfVRDOPrivatePlaintiffsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_CivilActionsInRespectOfTheUSAntiTerrorismActMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_CivilActionsInRespectOfTheUSAntiTerrorismActEDNYMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_CivilActionsInRespectOfTheUSAntiTerrorismActSDNYMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_HmRevenueCustomsHmrcAssessmentsConcerningUkValueAddedTaxMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_CategoriesOfRelatedPartiesAxis=bcs_BarclaysUkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=bcs_BarclaysBankPlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfContingentLiabilitiesAxis=bcs_BdcFinanceLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Legal, competition and regulatory matters (Details) £ in Millions, $ in Millions		3 Months Ended	6 Months Ended	12 Months Ended			150 Months Ended
	Jul. 02, 2026 challenge	Mar. 31, 2026 GBP (£)	Jun. 30, 2026 GBP (£) bank lawsuit	Dec. 31, 2024 subsidiarie	Dec. 31, 2018 GBP (£)	Dec. 31, 2008 USD ($)	Jun. 30, 2026 GBP (£) lawsuit plaintiff	Dec. 31, 2025 GBP (£)
Disclosure of contingent liabilities [line items]
Provisions \| £			£ 1,681				£ 1,681	£ 1,664
Motor finance commission arrangements
Disclosure of contingent liabilities [line items]
Increase in provision \| £		£ 105
Provisions \| £			£ 430				£ 430	£ 325
Number of legal challenges \| challenge	4
Motor finance commission arrangements \| Minimum
Disclosure of contingent liabilities [line items]
Compensatory interest			0.03
Civil actions in respect of USD LIBOR
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought			1
US residential and commercial mortgage-related activity and litigation \| Originated and sold to third parties by acquired subsidiary \| RMBS repurchase requests
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought			1
Civil Actions in respect of VRDO - Private Plaintiffs
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought			3
Civil actions in respect of the US Anti-Terrorism Act
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought							8
Number of plaintiffs \| plaintiff							4,000
Civil actions in respect of the US Anti-Terrorism Act - EDNY
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought			6
Number of lawsuits dismissed			3
Number of lawsuits subject to appeal			1
Number of lawsuits consolidated into a separate lawsuit			2
Number of separate lawsuits			1
Number of initial lawsuits amended			1
Number of banks claims against \| bank			1
Civil actions in respect of the US Anti-Terrorism Act - SDNY
Disclosure of contingent liabilities [line items]
Number of lawsuits with specified damages sought			2
HMRC assessments concerning UK VAT
Disclosure of contingent liabilities [line items]
Loss contingency, damages sought, claimed amounts, value \| £					£ 181
Number of overseas subsidiaries denied VAT Grouping by the HMRC \| subsidiarie				1
HMRC assessments concerning UK VAT \| Barclays UK
Disclosure of contingent liabilities [line items]
Loss contingency, damages sought, claimed amounts, value \| £					128
Barclays Bank PLC \| BDC Finance LLC
Disclosure of contingent liabilities [line items]
Litigation settlements approved, value \| $						$ 298
Barclays Bank PLC \| HMRC assessments concerning UK VAT
Disclosure of contingent liabilities [line items]
Loss contingency, damages sought, claimed amounts, value \| £					£ 53