GROUP STATEMENT OF CHANGES IN EQUITY (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
GROUP STATEMENT OF CHANGES IN EQUITY
Cumulative translation loss within other reserves	$ 207	$ 388	$ 254

A component of equity representing exchange differences on translation of financial statements of foreign operations recognised in other comprehensive income and accumulated in equity. [Refer: Other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 21
-IssueDate 2017-01-01
-Paragraph 52
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=21&date=2017-03-01&anchor=para_52_b&doctype=Standard
-URIDate 2017-03-09

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