Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financial Assets
Equity securities	$ 47.5	$ 34.8
Investments in debt securities	51.8	50.0
Financial Liabilities
Contingent payment obligations	0.0	0.0
Affiliate equity purchase obligations	194.2	161.2
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets
Equity securities	47.5	34.8
Investments in debt securities	0.0	0.0
Financial Liabilities
Contingent payment obligations	0.0	0.0
Affiliate equity purchase obligations	0.0	0.0
Significant Other Observable Inputs (Level 2)
Financial Assets
Equity securities	0.0	0.0
Investments in debt securities	51.8	50.0
Financial Liabilities
Contingent payment obligations	0.0	0.0
Affiliate equity purchase obligations	0.0	0.0
Significant Unobservable Inputs (Level 3)
Financial Assets
Equity securities	0.0	0.0
Investments in debt securities	0.0	0.0
Financial Liabilities
Contingent payment obligations	0.0	0.0
Affiliate equity purchase obligations	$ 194.2	$ 161.2