Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net (loss) income	$ (1,068.1)	$ 459.8	$ (510.5)	$ 1,047.7
Adjustments to reconcile net (loss) income to net cash flows from operating activities:
Depreciation and amortization			179.1	193.7
Change in fair value of contingent consideration	15.8	6.1	21.6	(22.6)
Share-based compensation expense			125.0	117.6
Deferred taxes (benefit)			(226.6)	(40.8)
Unrealized foreign currency loss (gain)			3.3	(4.1)
Unrealized (gain) loss on forward contracts			(11.5)	11.3
Unrealized gain on strategic equity investments			(25.8)	(8.6)
Inventory obsolescence charge			17.2	0.0
Impairment of intangible assets	2,053.3	0.0	2,053.3	0.0
Other			10.5	(2.3)
Changes in operating assets and liabilities, excluding the effect of acquisitions:
Accounts receivable			(137.6)	(196.4)
Inventories			(15.1)	(24.0)
Prepaid expenses, right of use operating assets and other assets			(54.8)	(126.8)
Accounts payable, accrued expenses, lease liabilities and other liabilities			(88.5)	23.6
Net cash provided by operating activities			1,339.6	968.3
Cash flows from investing activities:
Purchases of available-for-sale debt securities			(19.4)	(41.1)
Proceeds from maturity or sale of available-for-sale debt securities			166.3	139.3
Purchases of mutual funds related to nonqualified deferred compensation plan			(9.5)	(10.9)
Proceeds from sale of mutual funds related to nonqualified deferred compensation plan			5.3	9.0
Purchases of property, plant and equipment			(18.4)	(82.8)
Payment for acquisition of business, net of cash acquired			(837.7)	0.0
Purchases of strategic equity investments and options			(38.1)	(43.8)
Purchase of intangible assets			0.0	(8.0)
Other			0.0	0.2
Net cash used in investing activities			(751.5)	(38.1)
Cash flows from financing activities:
Payments on term loan			(65.3)	(32.7)
Payments on revolving credit facility			0.0	(250.0)
Repurchases of common stock			(360.8)	(48.9)
Net proceeds from issuance of common stock under share-based compensation arrangements			12.9	20.5
Other			(17.5)	(2.4)
Net cash used in financing activities			(430.7)	(313.5)
Effect of exchange rate changes on cash and cash equivalents and restricted cash			(8.1)	0.7
Net change in cash and cash equivalents and restricted cash			149.3	617.4
Cash and cash equivalents and restricted cash at beginning of period			2,723.6	1,367.3	$ 1,367.3
Cash and cash equivalents and restricted cash at end of period	2,872.9	1,984.7	2,872.9	1,984.7	2,723.6
Supplemental cash flow disclosures from investing and financing activities:
Contingent consideration issued in acquisitions			155.0	0.0
Fair value of strategic investment and purchase option acquired, less upfront cash paid			0.0	27.4
Operating ROU lease assets obtained in exchange for operating lease liabilities			15.9	20.7
Accounts payable and accrued expenses for purchases of property, plant and equipment and intangible assets			12.0	14.3
Cash and cash equivalents	2,825.0	1,984.2	2,825.0	1,984.2	$ 2,685.5
Restricted cash included in other current assets	47.8	0.1	47.8	0.1
Restricted cash included in other noncurrent assets	$ 0.1	$ 0.4	$ 0.1	$ 0.4