Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Changes in Goodwill
Goodwill, January 1			$ 10,677.4	$ 10,082.3
Goodwill, Acquisitions			2.5	751.1
Goodwill, Noncontrolling interests in acquired businesses			2.6	24.4
Goodwill, Contingent purchase price obligations of acquired businesses			2.6	0.0
Goodwill, Dispositions			(66.3)	(6.0)
Goodwill, Foreign currency translation			296.4	76.2
Goodwill, September 30	$ 10,915.2	$ 10,928.0	10,915.2	10,928.0
Goodwill, impairment losses			0.0	0.0
Goodwill, accumulated impairment losses	0.0		0.0
Intangible assets:
Intangible assets, Gross Carrying Value	1,355.8		1,355.8		$ 1,354.4
Intangible assets, Accumulated Amortization	(867.0)		(867.0)		(832.4)
Intangible assets, Net Carrying Value	488.8		488.8		522.0
Amortization of intangible assets	25.4	26.5	75.0	78.6
Acquired intangible assets and internally developed strategic platform assets
Intangible assets:
Intangible assets, Gross Carrying Value	1,079.0		1,079.0		1,096.1
Intangible assets, Accumulated Amortization	(623.4)		(623.4)		(606.1)
Intangible assets, Net Carrying Value	455.6		455.6		490.0
Amortization of intangible assets	21.5	22.2	63.1	65.2
Other purchased and internally developed software
Intangible assets:
Intangible assets, Gross Carrying Value	276.8		276.8		258.3
Intangible assets, Accumulated Amortization	(243.6)		(243.6)		(226.3)
Intangible assets, Net Carrying Value	33.2		33.2		$ 32.0
Amortization of intangible assets	$ 3.9	$ 4.3	$ 11.9	$ 13.4