Financing (2025 Debt Issuances) (Details) - CHF (SFr) SFr in Millions	Dec. 31, 2025	Oct. 10, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Debt instrument, face amount		SFr 1,250
2027 CHF Bonds | Bonds
Debt Instrument [Line Items]
Debt instrument, face amount	SFr 250	SFr 250	SFr 250
Stated Annual Interest Rate	0.4773%	0.4773%	0.4773%
2029 CHF Bonds | Bonds
Debt Instrument [Line Items]
Debt instrument, face amount	SFr 325	SFr 325	SFr 325
Stated Annual Interest Rate	0.8875%	0.8875%	0.8875%
2033 CHF Bonds | Bonds
Debt Instrument [Line Items]
Debt instrument, face amount	SFr 325	SFr 325	SFr 325
Stated Annual Interest Rate	1.265%	1.265%	1.265%
2037 CHF Bonds | Bonds
Debt Instrument [Line Items]
Debt instrument, face amount	SFr 225	SFr 225	SFr 225
Stated Annual Interest Rate	1.6249%	1.6249%	1.6249%
2045 CHF Bonds | Bonds
Debt Instrument [Line Items]
Debt instrument, face amount	SFr 125	SFr 125	SFr 125
Stated Annual Interest Rate	1.94%	1.94%	1.94%