Fair Value (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Carrying Amount
Assets:
Cash and cash equivalents	$ 4,431.2		$ 5,600.5
Marketable equity securities	1.2		1.6
Non-marketable equity securities	6.6		8.9
Foreign currency derivatives	0.1		0.6
Liabilities:
Short-term debt	10.2		3.9
Foreign currency derivatives	0.3		0.3
Contingent purchase price obligations	146.6		71.9
Long-term debt	5,217.7		5,807.3
Fair Value
Assets:
Cash and cash equivalents	4,431.2		5,600.5
Marketable equity securities	1.2		1.6
Non-marketable equity securities	6.6		8.9
Foreign currency derivatives	0.1		0.6
Liabilities:
Short-term debt	10.2		3.9
Foreign currency derivatives	0.3		0.3
Contingent purchase price obligations	146.6		71.9
Long-term debt	5,669.0		6,380.6
Contingent purchase price obligations
Changes in Contingent Purchase Price Obligations [Roll Forward]
January 1	71.9	$ 107.7
Acquisitions	92.3	10.0
Revaluation and interest	0.7	2.0
Payments	(16.8)	(25.4)
Foreign currency translation	(1.5)	1.0
September 30	146.6	$ 95.3
Fair Value, Recurring [Member]
Assets:
Cash and cash equivalents	4,431.2		5,600.5
Marketable equity securities	1.2		1.6
Foreign currency derivatives	0.1		0.6
Liabilities:
Foreign currency derivatives	0.3		0.3
Contingent purchase price obligations	146.6		71.9
Fair Value, Recurring [Member] | Level 1
Assets:
Cash and cash equivalents	4,431.2		5,600.5
Marketable equity securities	1.2		1.6
Fair Value, Recurring [Member] | Level 2
Assets:
Foreign currency derivatives	0.1		0.6
Liabilities:
Foreign currency derivatives	0.3		0.3
Fair Value, Recurring [Member] | Level 3
Liabilities:
Contingent purchase price obligations	$ 146.6		$ 71.9