Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash and cash equivalents	$ 3,002.2	$ 2,605.2
Short-term investments	20.6	14.5
Available-for-sale securities	4.3	4.8
Interest rate and foreign currency derivative instruments	0.2	32.4
Cost method investments	14.2	21.5
Liabilities:
Short-term debt	28.7	5.2
Interest rate and foreign currency derivative instruments	48.9	15.9
Contingent purchase price obligations	386.1	322.0
Long-term debt, including current portion	5,035.1	4,655.9
Carrying Amount
Assets:
Cash and cash equivalents	3,002.2	2,605.2
Short-term investments	20.6	14.5
Available-for-sale securities	4.3	4.8
Interest rate and foreign currency derivative instruments	0.2	32.4
Cost method investments	14.2	21.5
Liabilities:
Short-term debt	28.7	5.2
Interest rate and foreign currency derivative instruments	48.9	15.9
Contingent purchase price obligations	386.1	322.0
Long-term debt, including current portion	4,920.6	4,565.6
Contingent purchase price obligations
Changes in Level 3 Contingent Purchase Price Obligations [Roll Forward]
January 1	322.0	300.7
Acquisitions	165.3	98.9
Revaluation and interest	18.0	21.8
Payments	(103.7)	(58.6)
Deferred payment	0.0	(21.4)
Foreign currency translation	(15.5)	(19.4)
December 31	386.1	322.0
Fair Value, Measurements, Recurring [Member]
Assets:
Cash and cash equivalents	3,002.2	2,605.2
Short-term investments	20.6	14.5
Available-for-sale securities	4.3	4.8
Interest rate and foreign currency derivative instruments	0.2	32.4
Liabilities:
Interest rate and foreign currency derivative instruments	48.9	15.9
Contingent purchase price obligations	386.1	322.0
Fair Value, Measurements, Recurring [Member] | Level 1
Assets:
Cash and cash equivalents	3,002.2	2,605.2
Short-term investments	20.6	14.5
Available-for-sale securities	4.3	4.8
Fair Value, Measurements, Recurring [Member] | Level 2
Assets:
Interest rate and foreign currency derivative instruments	0.2	32.4
Liabilities:
Interest rate and foreign currency derivative instruments	48.9	15.9
Fair Value, Measurements, Recurring [Member] | Level 3
Liabilities:
Contingent purchase price obligations	$ 386.1	$ 322.0