Goodwill and Other Intangible Assets - Schedule of Goodwill and Other Intangible Assets Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill
Goodwill, beginning balance	$ 168.8	$ 176.5
Acquisitions of businesses	270.4	0.0
Finite-Lived Intangible Assets Acquired	0.3	0.0
Dispositions	0.0	(6.7)
Measurement period adjustments	0.0	(1.0)
Goodwill, ending balance	439.2	168.8	$ 176.5
Other Intangible Assets
Other intangible assets (excluding goodwill), beginning balance	201.8	215.9
Acquisition of businesses	101.0	0.0
Dispositions of businesses	0.0	(6.9)
Amortization	(22.0)	(7.2)	(5.2)
Other intangible assets (excluding goodwill), ending balance	281.1	201.8	215.9
Total Goodwill and Other Intangible Assets
Total Goodwill and Other Intangible Assets, beginning balance	370.6	392.4
Acquisition of businesses	371.4	0.0
Acquisition of intangible assets	0.3	0.0
Disposition of businesses	0.0	(13.6)
Measurement period adjustments	0.0	(1.0)
Amortization	(22.0)	(7.2)	(5.2)
Total Goodwill and Other Intangible Assets, ending balance	$ 720.3	$ 370.6	$ 392.4