Segmental Information - Summary of Information by Reportable Segment - Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Disclosure of operating segments [line items]
Assets held for sale	$ 19
Liabilitites classified as held for sale	22
EMEAA [member]
Disclosure of operating segments [line items]
Assets held for sale	19	$ 0
Liabilitites classified as held for sale	$ 22	$ 0

The amount of liabilities included in disposal groups classified as held for sale. [Refer: Liabilities; Disposal groups classified as held for sale [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 5
-IssueDate 2019-01-01
-Paragraph 38
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2019-en-r&anchor=para_38&doctype=Standard
-URIDate 2019-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2019-01-01
-Paragraph 54
-Subparagraph p
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2019-en-r&anchor=para_54_p&doctype=Standard
-URIDate 2019-03-27

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