Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2022	Dec. 31, 2021
Fair value assets and liabilities measured on recurring and nonrecurring basis
Contingent acquisition liability, total change		$ (8.9)
Long-term Debt, Fair Value		$ 2,696.0	$ 3,337.4
Discount rate floor contingent acquisition obligations		2.00%
Discount rate ceiling contingent acquisition obligations		5.00%
Discount rate floor long-term debt		0.40%
Discount rate ceiling long-term debt		3.40%
Level 1
Fair value assets and liabilities measured on recurring and nonrecurring basis
Cash equivalents		$ 1,188.8	2,391.8
Contingent acquisition obligations	[1]	0.0	0.0
Long-term Debt, Fair Value		0.0	0.0
Level 2
Fair value assets and liabilities measured on recurring and nonrecurring basis
Cash equivalents		0.0	0.0
Contingent acquisition obligations	[1]	0.0	0.0
Long-term Debt, Fair Value		2,658.4	3,295.6
Level 3
Fair value assets and liabilities measured on recurring and nonrecurring basis
Cash equivalents		0.0	0.0
Contingent acquisition obligations	[1]	24.6	33.5
Long-term Debt, Fair Value		37.6	41.8
Fair Value, Total [Member]
Fair value assets and liabilities measured on recurring and nonrecurring basis
Cash equivalents		1,188.8	2,391.8
Contingent acquisition obligations	[1]	24.6	33.5
Long-term Debt, Fair Value		$ 2,696.0	$ 3,337.4

[1] Contingent acquisition obligations includes deferred acquisition payments and unconditional obligations to purchase additional non-controlling equity shares of consolidated subsidiaries. Fair value measurement of the obligations is based upon actual and projected operating performance targets as specified in the related agreements. The decrease in this balance of $8.9 from December 31, 2021 to June 30, 2022 is primarily due to valuation adjustments and payments related to our deferred acquisitions payments from prior-year acquisitions. The amounts payable within the next twelve months are classified in accrued liabilities; any amounts payable thereafter are classified in other non-current liabilities.