Changes in organization and disposals - Sales of subsidiaries and businesses (Narrative) (Detail) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)
Disclosure Of Sale Of Subsidiaries And Businesses [Line Items]
Gains (losses) recognised when control is lost	$ 153
UBS AG
Disclosure Of Sale Of Subsidiaries And Businesses [Line Items]
Gains (losses) recognised when control is lost	$ 153

The gains (losses) recognised in association with the loss of control over a subsidiary, which are attributable to the former controlling interest.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2018-01-01
-Paragraph 19
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_19&doctype=Standard
-URIDate 2018-03-16

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