CONSOLIDATED CASH FLOW STATEMENT (Details) - Schedule of Change in Operating Assets - GBP (£) £ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Change in Operating Assets [Abstract]
Change in loans and receivables	£ (24,747)	£ 710	£ 6,081
Change in derivative financial instruments, trading and other financial assets at fair value through profit or loss	9,916	(13,889)	20,689
Change in other operating assets	(661)	961	7,930
Change in operating assets	£ (15,492)	£ (12,218)	£ 34,700

Adjustments for decrease (increase) in other assets to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other assets; Profit (loss)]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2016-01-13
-Paragraph 20
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=7&date=2016-03-30&anchor=para_20&doctype=Standard
-URIDate 2016-03-31

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