Amount of investment in equity security without readily determinable fair value.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117539-209714

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Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117539-209714

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of impairment of investments in privately held companies.

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Number of Impaired Investments

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Number of Investments

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Investments - Investments in Privately-Held Companies (Details) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2021 USD ($) investment	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) investment	Jun. 30, 2021 USD ($) investment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Investments in Privately-Held Companies and Investments in Equity Securities with Readily Determinable Fair Values
Impairments of investments in privately-held companies	$ 2.3	$ 0.0		$ 2.3	$ 5.6
Privately-held Companies
Investments in Privately-Held Companies and Investments in Equity Securities with Readily Determinable Fair Values
Investments in privately-held companies	$ 83.8			$ 83.8		$ 84.8
Number of impaired investments \| investment	2		2	2
Impairments of investments in privately-held companies	$ 2.3		$ 5.6		$ 5.6
Number of investments \| investment			1
Increase in the value of investment			$ 22.5