Goodwill and Other Intangible Assets - Schedule of Goodwill and Other Intangible Assets Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Goodwill
Goodwill, beginning Balance	$ 534.6	$ 439.2	$ 439.2	$ 168.8
Acquisition of businesses	595.4	0.0	690.8	270.4
Attribution of acquisition date fair value estimates between goodwill and other intangible assets	(37.7)	0.0	(37.7)	0.0
Goodwill, ending balance	1,092.3	439.2	1,092.3	439.2
Other Intangible Assets
Other intangible assets (excluding goodwill), beginning balance	270.8	291.8	281.1	201.8
Acquisition of businesses	0.0	0.0	0.0	101.0
Acquisition of intangible assets			0.0	0.3
Attribution of acquisition date fair value estimates between goodwill and other intangible assets	37.6	0.0	37.6	0.0
Amortization	(7.8)	(5.3)	(18.1)	(16.6)
Other intangible assets (excluding goodwill), ending balance	300.6	286.5	300.6	286.5
Total Goodwill and Other Intangible Assets
Total Goodwill and Other Intangible Assets, beginning balance	805.4	731.0	720.3	370.6
Acquisition of businesses	595.4	0.0	690.8	371.4
Acquisition of intangible assets			0.0	0.3
Attribution of acquisition date fair value estimates between goodwill and other intangible assets	(0.1)	0.0	(0.1)	0.0
Amortization	(7.8)	(5.3)	(18.1)	(16.6)
Total Goodwill and Other Intangible Assets, ending balance	$ 1,392.9	$ 725.7	$ 1,392.9	$ 725.7