Sale of businesses - Narrative (Details) - 6 months ended Dec. 31, 2019 £ in Millions, $ in Millions	GBP (£)	USD ($)
Disposal group, disposed of by sale, not discontinued operations \| Portfolio of 19 brands
Disclosure of business disposal [line items]
Aggregate consideration	£ 435	$ 550

The portion of consideration paid or received, consisting of cash and cash equivalents, in respect of both obtaining and losing control of subsidiaries or other businesses. [Refer: Subsidiaries [member]; Cash and cash equivalents; Consideration paid (received)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2019-01-01
-Paragraph 40
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2019-en-r&anchor=para_40_b&doctype=Standard
-URIDate 2019-03-27

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration