Summary of Significant Accounting Policies - Equity Instruments and Debt Securities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Equity Instruments and Investments
Equity instruments with readily determinable fair value	$ 118.5	$ 97.7
Equity instruments without readily determinable fair values	323.1	240.2
Debt securities of our captive insurance companies	$ 107.3	$ 79.7
Securities in captive insurance subsidiary portfolio | Maximum
Equity Instruments and Investments
Short-term investment maturity period	1 year
Investment maturity period	10 years