Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net revenues:
Net revenues:		$ 4,445.1	$ 4,445.4	$ 4,647.5
Cost of revenues:
Cost of revenues:		1,871.4	1,828.6	1,906.3
Gross margin		2,573.7	2,616.8	2,741.2
Operating expenses:
Research and development		958.4	955.7	1,003.2
Sales and marketing		938.8	939.3	927.4
General and administrative		255.4	244.3	231.1
Restructuring charges		68.0	35.3	7.3
Total operating expenses		2,220.6	2,174.6	2,169.0
Operating income		353.1	442.2	572.2
Loss on extinguishment of debt		(55.0)	(15.3)	0.0
Other expense, net	[1]	(32.9)	(12.5)	(39.5)
Income before income taxes		265.2	414.4	532.7
Income tax provision (benefit)		7.4	69.4	(34.2)
Net income		$ 257.8	$ 345.0	$ 566.9
Earnings Per Share [Abstract]
Basic (in dollars per share)		$ 0.78	$ 1.01	$ 1.62
Diluted (in dollars per share)		$ 0.77	$ 0.99	$ 1.60
Shares used in computing net income per share:
Basic (in shares)		330.4	343.2	349.0
Diluted (in shares)		335.2	348.2	354.4
Product
Net revenues:
Net revenues:		$ 2,845.0	$ 2,867.7	$ 3,107.1
Cost of revenues:
Cost of revenues:		1,278.6	1,227.0	1,277.2
Service
Net revenues:
Net revenues:		1,600.1	1,577.7	1,540.4
Cost of revenues:
Cost of revenues:		$ 592.8	$ 601.6	$ 629.1

[1] The amount for the year ended December 31, 2019 has been reclassified to conform to the current period presentation.