Segment reporting (Narrative) (Detail)	12 Months Ended
Dec. 31, 2020
Disclosure Of Operating Segments [Line Items]
Number of business divisions	4
UBS AG
Disclosure Of Operating Segments [Line Items]
Number of business divisions	4

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

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