Equity Method Eligible Investments - Balance Sheet and Income Statement Tables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investments in unconsolidated affiliates
Total assets	$ 9,925.6	$ 8,385.9
Total liabilities	4,794.6	3,824.3
Total revenues	2,239.8	2,166.7	$ 1,157.9
Total expenses	1,923.1	1,601.3	1,307.3
Net income (loss)	284.1	580.9	712.4
Equity Method Investment, Nonconsolidated Investee, Excluding MediaAlpha
Investments in unconsolidated affiliates
Total assets	3,719.1	3,203.2
Total liabilities	1,063.9	905.6
Total revenues	2,011.8	1,575.4	1,194.4
Total expenses	1,634.9	1,126.2	1,047.4
Net income (loss)	$ 376.9	$ 449.2	$ 147.0