Income Taxes - Reconciliation of the Effective Income Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amount
Federal statutory tax rate	$ 137.5
Other adjustments	0.2
Valuation allowances	3.5
Unrecognized tax benefits	(0.3)
Effective tax rate	$ 121.5	$ 188.4	$ (84.4)
Percent
Federal statutory tax rate	25.00%	25.00%	23.50%
Tax rate differential		(2.70%)	(4.90%)
Other adjustments	0.00%
Change in other valuation allowances	0.70%	0.60%	0.30%
Unrecognized tax benefits	(0.10%)
Effective tax rate	22.10%	43.90%	(22.50%)
Switzerland
Amount
Tax rate differential	$ (44.8)
Cantonal income taxes	20.3
Other adjustments	$ 3.7
Percent
Tax rate differential	(8.10%)
Cantonal income taxes	3.60%
Other adjustments	0.70%
Other
Amount
Tax rate differential	$ 5.7
Percent
Tax rate differential	1.00%
United States
Amount
Tax rate differential	$ (10.6)
Other adjustments	(7.3)
State and local income taxes	$ 13.6
Percent
Tax rate differential	(1.90%)
Other adjustments	(1.30%)
State and local income taxes	2.50%