Principal subsidiaries - Significant subsidiaries (Details)	12 Months Ended
Dec. 31, 2022
Barclays Bank Delaware
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%
Barclays Bank Ireland PLC
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%
Barclays Capital Inc.
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%
Barclays Capital Securities Limited
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%
Barclays Securities Japan Limited
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%
Barclays US LLC
Disclosure of subsidiaries [line items]
Percentage of voting rights held	100.00%
Non-controlling interests - proportion of ownership interests	0.00%
Non-controlling interests - proportion of voting interests	0.00%

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.

No definition available.

+ Details

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

- Definition

The proportion of ownership interests in a subsidiary held by non-controlling interests. [Refer: Subsidiaries [member]; Non-controlling interests]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2022-03-24
-Paragraph 12
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2022-en-r&anchor=para_12_c&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The proportion of the voting rights in a subsidiary held by the entity. [Refer: Subsidiaries [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2022-03-24
-Paragraph 17
-Subparagraph b
-Clause iii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2022-en-r&anchor=para_17_b_iii&doctype=Standard
-URIDate 2022-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2022-03-24
-Paragraph 16
-Subparagraph b
-Clause iii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2022-en-r&anchor=para_16_b_iii&doctype=Standard
-URIDate 2022-03-24

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2022-03-24
-Paragraph 19B
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2022-en-r&anchor=para_19B_c&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_ProportionOfVotingPowerHeldInSubsidiary
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The proportion of the voting rights in a subsidiary held by non-controlling interests. [Refer: Subsidiaries [member]; Non-controlling interests]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2022-03-24
-Paragraph 12
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2022-en-r&anchor=para_12_d&doctype=Standard
-URIDate 2022-03-24

+ Details

Name:	ifrs-full_ProportionOfVotingRightsHeldByNoncontrollingInterests
Namespace Prefix:	ifrs-full_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysBankDelawareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysBankIrelandPlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysCapitalIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysCapitalSecuritiesLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysSecuritiesJapanLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=bbplc_BarclaysUsLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: