Earnings per share (EPS) and shares outstanding (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Basic earnings
Net profit / (loss) attributable to shareholders	$ 1,194	$ 1,421	$ 1,307	$ 2,615	$ 2,375
Diluted earnings
Net profit / (loss) attributable to shareholders	$ 1,194	$ 1,421	$ 1,307	$ 2,615	$ 2,375

The profit (loss) attributable to ordinary equity holders of the parent entity. [Refer: Profit (loss)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 33
-IssueDate 2019-01-01
-Paragraph 70
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=33&code=ifrs-tx-2019-en-r&anchor=para_70_a&doctype=Standard
-URIDate 2019-03-27

Name:	ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration