Provisions - Narrative (Details) - CHF (SFr) SFr in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of Provisions [Line Items]
Other provisions	SFr 33.7	SFr 36.6	SFr 17.1
Asset retirement obligation
Disclosure of Provisions [Line Items]
Other provisions	SFr 11.4	SFr 5.9

The amount of provisions other than provisions for employee benefits. [Refer: Provisions]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 37
-IssueDate 2025-01-01
-Paragraph 84
-Subparagraph a
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-URIDate 2025-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph B9
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B9_e&doctype=Appendix&subtype=B
-URIDate 2025-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 257
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257_a&doctype=Standard
-URIDate 2025-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2027-01-01
-Name IFRS
-Number 19
-IssueDate 2025-01-01
-Paragraph 257
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257_a&doctype=Standard
-URIDate 2025-03-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 78
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_d&doctype=Standard
-URIDate 2025-03-27

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