Fair Value (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Contingent purchase price obligations	Mar. 31, 2013 Contingent purchase price obligations	Mar. 31, 2014 Contingent purchase price obligations Interest Expense [Member]	Mar. 31, 2013 Contingent purchase price obligations Interest Expense [Member]	Mar. 31, 2014 Carrying Amount	Dec. 31, 2013 Carrying Amount	Mar. 31, 2014 Fair Value	Dec. 31, 2013 Fair Value	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 1	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Level 1	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 2	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Level 2	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Level 3	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Level 3	Mar. 31, 2014 Fair Value, Measurements, Recurring [Member] Total	Dec. 31, 2013 Fair Value, Measurements, Recurring [Member] Total
Assets:
Cash and cash equivalents							$ 2,082.1	$ 2,710.5	$ 2,082.1	$ 2,710.5	$ 2,082.1	$ 2,710.5					$ 2,082.1	$ 2,710.5
Short-term investments	7.0	18.2					7.0	18.2	7.0	18.2	7.0	18.2					7.0	18.2
Available-for-sale securities							5.0	4.9	5.0	4.9	5.0	4.9					5.0	4.9
Forward foreign exchange contracts							0.7	2.2	0.7	2.2			0.7	2.2			0.7	2.2
Cost method investments							21.7	22.2	21.7	22.2
Liabilities:
Short-term borrowings							7.5	5.9	7.5	5.9
Forward foreign exchange contracts							0.1	0.1	0.1	0.1			0.1	0.1			0.1	0.1
Contingent interest derivative							1.4	2.1	1.4	2.1			1.4	2.1			1.4	2.1
Contingent purchase price obligations							256.8	220.2	256.8	220.2					256.8	220.2	256.8	220.2
Debt							4,031.7	4,033.8	4,335.5	4,302.7
Changes in Level 3 Contingent Purchase Price Obligations [Roll Forward]
Balance January 1			220.2	266.2
Acquisitions			43.2	1.6
Revaluation and interest					(0.8)	1.4
Payments			(7.8)	(13.5)
Foreign currency translation			2.0	(16.1)
Balance March 31			$ 256.8	$ 239.6