Income Taxes (Summary of Income Tax Expense (Recovery)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Domestic (Canada):
Current tax expense	$ 40.2	$ 74.3	$ 43.4
Deferred tax benefit	(0.2)	(5.7)	(2.7)
Foreign:
Current tax expense	122.0	132.2	98.8
Deferred tax benefit	(54.0)	(63.5)	(63.1)
Income tax expense	$ 108.0	$ 137.3	$ 76.4