Fair Value Measurements - Financial Assets and Liabilities Subject to Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financial instruments carried at fair value (liability position):
Long-term contingent consideration	$ (186.5)	$ (189.6)
Recurring basis
Financial instruments carried at fair value (asset position):
Derivative asset current, foreign currency forward contracts	44.5	0.0
Derivative asset noncurrent, foreign currency forward contracts	2.0	0.0
Total financial assets	4,254.5	3,811.8
Financial instruments carried at fair value (liability position):
Derivative liability current, foreign currency forward contracts	(5.6)	(59.2)
Long-term contingent consideration	(186.5)	(189.6)
Derivative liability noncurrent, foreign currency forward contracts	(2.7)	(4.3)
Total financial liabilities	(194.8)	(253.1)
Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Derivative asset current, foreign currency forward contracts	0.0	0.0
Derivative asset noncurrent, foreign currency forward contracts	0.0	0.0
Total financial assets	3,864.4	3,236.8
Financial instruments carried at fair value (liability position):
Derivative liability current, foreign currency forward contracts	0.0	0.0
Long-term contingent consideration	0.0	0.0
Derivative liability noncurrent, foreign currency forward contracts	0.0	0.0
Total financial liabilities	0.0	0.0
Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Derivative asset current, foreign currency forward contracts	44.5	0.0
Derivative asset noncurrent, foreign currency forward contracts	2.0	0.0
Total financial assets	390.1	575.0
Financial instruments carried at fair value (liability position):
Derivative liability current, foreign currency forward contracts	(5.6)	(59.2)
Long-term contingent consideration	0.0	0.0
Derivative liability noncurrent, foreign currency forward contracts	(2.7)	(4.3)
Total financial liabilities	(8.3)	(63.5)
Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Derivative asset current, foreign currency forward contracts	0.0	0.0
Derivative asset noncurrent, foreign currency forward contracts	0.0	0.0
Total financial assets	0.0	0.0
Financial instruments carried at fair value (liability position):
Derivative liability current, foreign currency forward contracts	0.0	0.0
Long-term contingent consideration	(186.5)	(189.6)
Derivative liability noncurrent, foreign currency forward contracts	0.0	0.0
Total financial liabilities	(186.5)	(189.6)
Money market funds \| Recurring basis
Financial instruments carried at fair value (asset position):
Cash equivalents:	3,478.1	3,141.1
Money market funds \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Cash equivalents:	3,478.1	3,141.1
Money market funds \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Cash equivalents:	0.0	0.0
Money market funds \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Cash equivalents:	0.0	0.0
Corporate equity securities \| Recurring basis
Financial instruments carried at fair value (asset position):
Marketable securities:	230.9	195.8
Corporate equity securities \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Marketable securities:	230.9	15.7
Corporate equity securities \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	180.1
Corporate equity securities \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
U.S. Treasury securities \| Recurring basis
Financial instruments carried at fair value (asset position):
Marketable securities:	86.4	0.0
U.S. Treasury securities \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Marketable securities:	86.4	0.0
U.S. Treasury securities \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
U.S. Treasury securities \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Government-sponsored enterprise securities \| Recurring basis
Financial instruments carried at fair value (asset position):
Marketable securities:	69.0	80.0
Government-sponsored enterprise securities \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Marketable securities:	69.0	80.0
Government-sponsored enterprise securities \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Government-sponsored enterprise securities \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Corporate debt securities \| Recurring basis
Financial instruments carried at fair value (asset position):
Marketable securities:	90.9	231.6
Corporate debt securities \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Corporate debt securities \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Marketable securities:	90.9	231.6
Corporate debt securities \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Commercial paper \| Recurring basis
Financial instruments carried at fair value (asset position):
Marketable securities:	252.7	163.3
Commercial paper \| Recurring basis \| Level 1
Financial instruments carried at fair value (asset position):
Marketable securities:	0.0	0.0
Commercial paper \| Recurring basis \| Level 2
Financial instruments carried at fair value (asset position):
Marketable securities:	252.7	163.3
Commercial paper \| Recurring basis \| Level 3
Financial instruments carried at fair value (asset position):
Marketable securities:	$ 0.0	$ 0.0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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