Income Tax - Narrative (Details) - USD ($) $ in Millions		3 Months Ended			12 Months Ended
	Aug. 31, 2025	Dec. 31, 2025	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax Contingency [Line Items]
Goodwill impairment			$ 3,645.7		$ 3,645.7	$ 0.0	$ 0.0
Changes in valuation allowance				$ 20.0
Non-taxable gains		$ 77.9
Non-deductible adjustment related to interest expense				$ 45.8
Reduction in cash tax payment due to OBBBA					$ 80.0
U.S. federal statutory tax rate					21.00%	21.00%	21.00%
Undistributed earnings of foreign subsidiaries		54.0			$ 54.0	$ 48.2
Remaining unrecognized tax benefits		14.6			14.6	$ 11.6
Significant change in unrecognized tax benefit		55.6			55.6
Domestic | General business tax credit carryforward
Income Tax Contingency [Line Items]
Capital loss carryforwards, tax effect		108.3			108.3
Operating loss carryforwards, not subject to expiration		17.4			17.4
Foreign | General business tax credit carryforward
Income Tax Contingency [Line Items]
Capital loss carryforwards, tax effect		189.0			189.0
Operating loss carryforwards, not subject to expiration		$ 41.9			$ 41.9
Minimum
Income Tax Contingency [Line Items]
Statutes of limitations, term					3 years
Minimum | Europe
Income Tax Contingency [Line Items]
U.S. federal statutory tax rate					9.00%
Minimum | Canada
Income Tax Contingency [Line Items]
U.S. federal statutory tax rate					15.00%
Maximum
Income Tax Contingency [Line Items]
Statutes of limitations, term					7 years
Maximum | Europe
Income Tax Contingency [Line Items]
U.S. federal statutory tax rate					25.80%
Maximum | Canada
Income Tax Contingency [Line Items]
U.S. federal statutory tax rate					11.00%
Americas
Income Tax Contingency [Line Items]
Goodwill impairment	$ 3,645.7				$ 3,645.7