The amount of investments in associates. [Refer: Associates [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2017-01-01
-Paragraph 10
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2017-03-01&anchor=para_10&doctype=Standard
-URIDate 2017-03-09

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

Basis of preparation and significant accounting policies (Details) - USD ($) $ in Millions	Jan. 01, 2018	Dec. 31, 2017
Disclosure of effect of overlay approach reclassification on profit or loss [line items]
Impact on transition to IFRS 9	$ 1,647
IFRS 9
Disclosure of effect of overlay approach reclassification on profit or loss [line items]
Investments in associates		$ 643