Employee benefits: variable compensation (Narrative) (Detail 2) $ in Millions	Dec. 31, 2023 USD ($) yr	Dec. 31, 2022 USD ($)
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Carrying amount of liability related to cash-settled share-based awards \| $	$ 64	$ 43
Unvested share-based awards
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Weighted average remaining contractual term (years) \| yr	2.2

The amount of liabilities arising from share-based payment transactions. Share-based payment transactions are transactions in which the entity: (a) receives goods or services from the supplier of those goods or services (including an employee) in a share-based payment arrangement; or (b) incurs an obligation to settle the transaction with the supplier in a share-based payment arrangement when another group entity receives those goods or services. [Refer: Share-based payment arrangements [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2023-01-01
-Paragraph 51
-Subparagraph b
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2023-en-r&anchor=para_51_b_i&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_LiabilitiesFromSharebasedPaymentTransactions2011
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant