TRANSFERS OF FINANCIAL ASSETS (Details) - GBP (£) £ in Millions	Dec. 31, 2019	Dec. 31, 2018
Securitisations [member]
TRANSFERS OF FINANCIAL ASSETS (Details) [Line Items]
Fair value of associated financial liabilities	£ 31,436	£ 31,701

The fair value of financial liabilities associated with transferred financial assets that are not derecognised in their entirety. [Refer: Financial assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 42D
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_42D_d&doctype=Standard
-URIDate 2019-03-27

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