Fair Value (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Carrying Amount
Assets:
Cash and cash equivalents	$ 4,897.3		$ 5,600.5
Marketable equity securities	1.4		1.6
Non-marketable equity securities	6.9		8.9
Foreign currency derivatives	0.5		0.6
Liabilities:
Short-term debt	5.9		3.9
Foreign currency derivatives	0.5		0.3
Contingent purchase price obligations	67.7		71.9
Long-term debt, including current portion	5,754.4		5,807.3
Fair Value
Assets:
Cash and cash equivalents	4,897.3		5,600.5
Marketable equity securities	1.4		1.6
Non-marketable equity securities	6.9		8.9
Foreign currency derivatives	0.5		0.6
Liabilities:
Short-term debt	5.9		3.9
Foreign currency derivatives	0.5		0.3
Contingent purchase price obligations	67.7		71.9
Long-term debt, including current portion	6,143.1		6,380.6
Contingent purchase price obligations
Changes in Contingent Purchase Price Obligations [Roll Forward]
January 1	71.9	$ 107.7
Acquisitions	1.3	8.1
Revaluation and interest	0.4	0.6
Payments	(5.4)	0.0
Foreign currency translation	(0.5)	(2.8)
March 31	67.7	$ 113.6
Fair Value, Recurring [Member]
Assets:
Cash and cash equivalents	4,897.3		5,600.5
Marketable equity securities	1.4		1.6
Foreign currency derivatives	0.5		0.6
Liabilities:
Foreign currency derivatives	0.5		0.3
Contingent purchase price obligations	67.7		71.9
Fair Value, Recurring [Member] | Level 1
Assets:
Cash and cash equivalents	4,897.3		5,600.5
Marketable equity securities	1.4		1.6
Fair Value, Recurring [Member] | Level 2
Assets:
Foreign currency derivatives	0.5		0.6
Liabilities:
Foreign currency derivatives	0.5		0.3
Fair Value, Recurring [Member] | Level 3
Liabilities:
Contingent purchase price obligations	$ 67.7		$ 71.9