Fair Value (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Assets:
Short-term investments	$ 1.6		$ 3.6
Carrying Amount
Assets:
Cash and cash equivalents	2,692.5		4,305.7
Short-term investments	1.6		3.6
Marketable equity securities	1.6		1.6
Non-marketable equity securities	9.5		9.0
Foreign currency derivatives	0.6		0.6
Liabilities:
Short-term debt	10.9		10.1
Foreign currency derivatives	1.0		0.4
Contingent purchase price obligations	113.6		107.7
Long-term debt, including current portion	5,093.4		5,134.3
Fair Value
Assets:
Cash and cash equivalents	2,692.5		4,305.7
Short-term investments	1.6		3.6
Marketable equity securities	1.6		1.6
Non-marketable equity securities	9.5		9.0
Foreign currency derivatives	0.6		0.6
Liabilities:
Short-term debt	10.9		10.1
Foreign currency derivatives	1.0		0.4
Contingent purchase price obligations	113.6		107.7
Long-term debt, including current portion	5,022.1		5,316.4
Contingent purchase price obligations
Changes in Contingent Purchase Price Obligations [Roll Forward]
January 1	107.7	$ 146.5
Acquisitions	8.1	1.8
Revaluation and interest	0.6	1.2
Payments	0.0	(2.5)
Foreign currency translation	(2.8)	(0.3)
March 31	113.6	$ 146.7
Fair Value, Recurring [Member]
Assets:
Cash and cash equivalents	2,692.5		4,305.7
Short-term investments	1.6		3.6
Marketable equity securities	1.6		1.6
Foreign currency derivatives	0.6		0.6
Liabilities:
Foreign currency derivatives	1.0		0.1
Contingent purchase price obligations	113.6		107.7
Fair Value, Recurring [Member] | Level 1
Assets:
Cash and cash equivalents	2,692.5		4,305.7
Short-term investments	1.6		3.6
Marketable equity securities	1.6		1.6
Fair Value, Recurring [Member] | Level 2
Assets:
Foreign currency derivatives	0.6		0.6
Liabilities:
Foreign currency derivatives	1.0		0.4
Fair Value, Recurring [Member] | Level 3
Liabilities:
Contingent purchase price obligations	$ 113.6		$ 107.7