Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Revision of Prior Period Change in Accounting Principle Adjustment [Member]	RSUs [Member]	Class A Common stock [Member]	Class A Common stock [Member] RSUs [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Treasury Stock [Member] RSUs [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Revision of Prior Period Change in Accounting Principle Adjustment [Member]
Beginning balance, Value at Dec. 31, 2019	$ 1,975.4	$ (0.4)				$ 3,898.7			$ (125.9)	$ (1,797.4)	$ (0.4)
Beginning balance, Shares at Dec. 31, 2019				950.0
Exercise of stock options and ESPP	8.8					8.8
Exercise of stock options and ESPP, Shares				2.5
Vesting of RSUs, net of tax withholdings			$ (14.8)					$ (14.8)
Vesting of RSUs, net of tax withholdings, Shares					3.3
Stock-based compensation expense	$ 20.5					20.5
Retirements of treasury stock							$ 14.8			(14.8)
Accounting Standards Update [Extensible Enumeration]	us-gaap:AccountingStandardsUpdate201613Member
Net income (loss)	$ (103.9)									(103.9)
Other comprehensive income (loss)	(30.0)								(30.0)
Ending balance, Value at Mar. 31, 2020	1,855.6					3,928.0			(155.9)	(1,916.5)
Ending balance, Shares at Mar. 31, 2020				955.8
Beginning balance, Value at Dec. 31, 2019	1,975.4	$ (0.4)				3,898.7			(125.9)	(1,797.4)	$ (0.4)
Beginning balance, Shares at Dec. 31, 2019				950.0
Net income (loss)	(376.4)
Other comprehensive income (loss)	19.0
Ending balance, Value at Sep. 30, 2020	2,813.4					5,137.4			(106.9)	(2,217.1)
Ending balance, Shares at Sep. 30, 2020				1,079.0
Beginning balance, Value at Mar. 31, 2020	1,855.6					3,928.0			(155.9)	(1,916.5)
Beginning balance, Shares at Mar. 31, 2020				955.8
Exercise of stock options and ESPP	1.9					1.9
Exercise of stock options and ESPP, Shares				0.6
Vesting of RSUs, net of tax withholdings			(14.3)					(14.3)
Vesting of RSUs, net of tax withholdings, Shares					2.4
Stock-based compensation expense	25.6					25.6
Retirements of treasury stock							14.3			(14.3)
Net income (loss)	(150.3)									(150.3)
Other comprehensive income (loss)	17.7								17.7
Ending balance, Value at Jun. 30, 2020	1,736.2					3,955.5			(138.2)	(2,081.1)
Ending balance, Shares at Jun. 30, 2020				958.8
Exercise of stock options and ESPP	5.4					5.4
Exercise of stock options and ESPP, Shares				1.1
Vesting of RSUs, net of tax withholdings			(13.8)					(13.8)
Vesting of RSUs, net of tax withholdings, Shares					2.5
Acquisition-related common stock issuance	1,137.7					1,137.7
Acquisition-related common stock issuance, Shares				116.6
Stock-based compensation expense	38.8					38.8
Retirements of treasury stock							13.8			(13.8)
Net income (loss)	(122.2)									(122.2)
Other comprehensive income (loss)	31.3								31.3
Ending balance, Value at Sep. 30, 2020	2,813.4					5,137.4			(106.9)	(2,217.1)
Ending balance, Shares at Sep. 30, 2020				1,079.0
Beginning balance, Value at Dec. 31, 2020	2,941.5					5,276.5			(50.7)	(2,284.3)
Beginning balance, Shares at Dec. 31, 2020				1,081.6
Exercise of stock options and ESPP	10.5					10.5
Exercise of stock options and ESPP, Shares				2.7
Vesting of RSUs, net of tax withholdings			(8.2)					(8.2)
Vesting of RSUs, net of tax withholdings, Shares					4.5
Stock-based compensation expense	37.2					37.2
Retirements of treasury stock							8.2			(8.2)
Net income (loss)	(23.0)									(23.0)
Other comprehensive income (loss)	(15.6)								(15.6)
Ending balance, Value at Mar. 31, 2021	2,942.4					5,324.2			(66.3)	(2,315.5)
Ending balance, Shares at Mar. 31, 2021				1,088.8
Beginning balance, Value at Dec. 31, 2020	2,941.5					5,276.5			(50.7)	(2,284.3)
Beginning balance, Shares at Dec. 31, 2020				1,081.6
Net income (loss)	(36.9)
Other comprehensive income (loss)	(24.7)								(24.7)
Ending balance, Value at Sep. 30, 2021	3,007.0					5,418.8			(75.4)	(2,336.4)
Ending balance, Shares at Sep. 30, 2021				1,100.2
Beginning balance, Value at Mar. 31, 2021	2,942.4					5,324.2			(66.3)	(2,315.5)
Beginning balance, Shares at Mar. 31, 2021				1,088.8
Exercise of stock options and ESPP	0.2					0.2
Exercise of stock options and ESPP, Shares				0.1
Vesting of RSUs, net of tax withholdings			(4.0)					(4.0)
Vesting of RSUs, net of tax withholdings, Shares					3.1
Stock-based compensation expense	43.2					43.2
Retirements of treasury stock							4.0			(4.0)
Net income (loss)	27.8									27.8
Other comprehensive income (loss)	11.0								11.0
Ending balance, Value at Jun. 30, 2021	3,020.6					5,367.6			(55.3)	(2,291.7)
Ending balance, Shares at Jun. 30, 2021				1,092.0
Exercise of stock options and ESPP	4.4					4.4
Exercise of stock options and ESPP, Shares				0.6
Vesting of RSUs, net of tax withholdings			$ (3.0)					$ (3.0)
Vesting of RSUs, net of tax withholdings, Shares					7.6
Acquisition-related stock option issuance	2.2					2.2
Stock-based compensation expense	44.6					44.6
Retirements of treasury stock							$ 3.0			(3.0)
Net income (loss)	(41.7)									(41.7)
Other comprehensive income (loss)	(20.1)								(20.1)
Ending balance, Value at Sep. 30, 2021	$ 3,007.0					$ 5,418.8			$ (75.4)	$ (2,336.4)
Ending balance, Shares at Sep. 30, 2021				1,100.2