Cash and Cash Equivalents (Excluding Overdrafts) - Summary of Cash and Cash Equivalents (Detail) - GBP (£) £ in Millions	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents [line items]
Cash at bank and in hand	£ 401	£ 533
Short-term bank deposits	36	35
Total	£ 437	£ 568

A classification of cash equivalents representing short-term deposits. [Refer: Cash equivalents]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 7
-IssueDate 2019-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2019-en-r&anchor=para_45&doctype=Standard
-URIDate 2019-03-27

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