Related party disclosure (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Entity [Table]
Fees	$ 36	$ 39
Fair value	265	252
UBS AG
Entity [Table]
Fees	20	22
Fair value	$ 253	$ 241

The amount of revenue arising from the rendering of services in related party transactions. [Refer: Revenue; Related parties [member]]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 24
-IssueDate 2021-01-01
-Paragraph 21
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=24&code=ifrs-tx-2021-en-r&anchor=para_21_c&doctype=Standard
-URIDate 2021-03-24

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