Financial result - Additional Information (Details) - CHF (SFr) SFr in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Analysis of income and expense [abstract]
Decrease in foreign exchange loss	SFr 44.0
Foreign exchange gain/(losses)	SFr (4.5)	SFr (48.5)	SFr 72.3	SFr (39.7)

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Financial instruments, class [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 21
-IssueDate 2023-01-01
-Paragraph 52
-Subparagraph a
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-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 35
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_35&doctype=Standard
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