Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Changes in Goodwill
Goodwill, January 1	$ 10,677.4	$ 10,082.3
Goodwill, Acquisitions	2.4	688.3
Goodwill, Noncontrolling interests in acquired businesses	2.5	0.0
Goodwill, Contingent purchase price obligations of acquired businesses	2.4	0.0
Goodwill, Dispositions	(20.6)	(5.9)
Goodwill, Foreign currency translation	117.4	(70.9)
Goodwill, March 31	10,781.5	10,693.8
Goodwill, impairment losses	0.0	0.0
Goodwill, accumulated impairment losses	0.0
Intangible assets:
Intangible assets, Gross Carrying Value	1,368.1		$ 1,354.4
Intangible assets, Accumulated Amortization	(855.2)		(832.4)
Intangible assets, Net Carrying Value	512.9		522.0
Amortization of intangible assets	25.8	25.8
Acquired intangible assets and internally developed strategic platform assets
Intangible assets:
Intangible assets, Gross Carrying Value	1,095.6		1,096.1
Intangible assets, Accumulated Amortization	(614.7)		(606.1)
Intangible assets, Net Carrying Value	480.9		490.0
Amortization of intangible assets	21.8	21.5
Other purchased and internally developed software
Intangible assets:
Intangible assets, Gross Carrying Value	272.5		258.3
Intangible assets, Accumulated Amortization	(240.5)		(226.3)
Intangible assets, Net Carrying Value	32.0		$ 32.0
Amortization of intangible assets	$ 4.0	$ 4.3