Cash and cash equivalents and investment securities - Summary of Investments in Short-Term Debt Securities (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Disclosure of detailed information about borrowings [abstract]
Investment in unquoted companies	$ 92	$ 85
Investment in debt securities	21	25
Non-current investments,Total	113	110
Investment in debt securities	102	92
Current investments,Total	$ 102	$ 92

The amount of current financial assets at fair value through other comprehensive income. [Refer: Financial assets at fair value through other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2019-01-01
-Paragraph 8
-Subparagraph h
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2019-en-r&anchor=para_8_h&doctype=Standard
-URIDate 2019-03-27

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