Fair Value (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Assets:
Short-term investments	$ 0.0		$ 3.6
Carrying Amount
Assets:
Cash and cash equivalents	3,278.3		4,305.7
Short-term investments	0.0		3.6
Marketable equity securities	1.5		1.6
Non-marketable equity securities	8.9		9.0
Foreign currency derivatives	0.3		0.6
Liabilities:
Short-term debt	23.6		10.1
Foreign currency derivatives	0.3		0.4
Contingent purchase price obligations	95.3		107.7
Long-term debt, including current portion	5,761.5		5,134.3
Fair Value
Assets:
Cash and cash equivalents	3,278.3		4,305.7
Short-term investments	0.0		3.6
Marketable equity securities	1.5		1.6
Non-marketable equity securities	8.9		9.0
Foreign currency derivatives	0.3		0.6
Liabilities:
Short-term debt	23.6		10.1
Foreign currency derivatives	0.3		0.4
Contingent purchase price obligations	95.3		107.7
Long-term debt, including current portion	6,242.7		5,316.4
Contingent purchase price obligations
Changes in Contingent Purchase Price Obligations [Roll Forward]
January 1	107.7	$ 146.5
Acquisitions	10.0	42.9
Revaluation and interest	2.0	2.2
Payments	(25.4)	(43.7)
Foreign currency translation	1.0	(3.0)
September 30	95.3	$ 144.9
Fair Value, Recurring [Member]
Assets:
Cash and cash equivalents	3,278.3		4,305.7
Short-term investments	0.0		3.6
Marketable equity securities	1.5		1.6
Foreign currency derivatives	0.3		0.6
Liabilities:
Foreign currency derivatives	0.3		0.4
Contingent purchase price obligations	95.3		107.7
Fair Value, Recurring [Member] | Level 1
Assets:
Cash and cash equivalents	3,278.3		4,305.7
Short-term investments	0.0		3.6
Marketable equity securities	1.5		1.6
Fair Value, Recurring [Member] | Level 2
Assets:
Foreign currency derivatives	0.3		0.6
Liabilities:
Foreign currency derivatives	0.3		0.4
Fair Value, Recurring [Member] | Level 3
Liabilities:
Contingent purchase price obligations	$ 95.3		$ 107.7