Right-of-use assets - Narrative (Details) - CHF (SFr) SFr in Millions	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023
Disclosure of quantitative information about right-of-use assets [abstract]
Additions	SFr 121.0	SFr 20.2

The amount of additions to right-of-use assets. [Refer: Right-of-use assets]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2023-01-01
-Paragraph 53
-Subparagraph h
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2023-en-r&anchor=para_53_h&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_AdditionsToRightofuseAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration