Asset transfers - Assets pledged as collateral (Details) - GBP (£) £ in Millions	Dec. 31, 2020	Dec. 31, 2019
Asset transfers
Assets pledged against liabilities	£ 49,682	£ 50,565
Trading assets
Asset transfers
Assets pledged against liabilities	28,728	27,918
Loans to banks - amortised cost
Asset transfers
Assets pledged against liabilities	49	39
Loans to customers - amortised cost
Asset transfers
Assets pledged against liabilities	15,939	17,920
Other financial assets
Asset transfers
Assets pledged against liabilities	£ 4,966	£ 4,688

The amount of financial assets that the entity has pledged as collateral for liabilities or contingent liabilities, including amounts that have been reclassified in accordance with paragraph 3.2.23(a) of IFRS 9. [Refer: Contingent liabilities [member]; Financial assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2020-01-01
-Paragraph 14
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2020-en-r&anchor=para_14_a&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant