The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Subsidiaries [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2019-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_17_b_iii&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2019-01-01
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=27&code=ifrs-tx-2019-en-r&anchor=para_16_b_iii&doctype=Standard
-URIDate 2019-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2019-01-01
-Paragraph 19B
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2019-en-r&anchor=para_19B_c&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_ProportionOfOwnershipInterestInSubsidiary
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Reconciliation of movement in net borrowings - Narrative (Details) € in Millions, £ in Millions, $ in Millions	6 Months Ended
	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 EUR (€)
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Proportion of ownership interest in subsidiary	100.00%
European Debt Issuance Programme
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Bonds issued	£ 1,289	$ 1,600	£ 1,754	€ 2,000