Fair Value Measurements, Equity Investments and Other Financial Instruments - Equity Investment Without Readily Determinable Fair Value (Details) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) investment	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Equity Securities without Readily Determinable Fair Value [Roll Forward]
Carrying amount at the beginning of period	$ 25.4		$ 7.5	$ 7.5
Purchases	5.7			2.6
Impairments or downward adjustments	0.0			0.0
Upward adjustments	0.0			15.1
Currency translation on investments	(0.4)			0.2
Carrying amount at the end of period	30.7	$ 25.4		25.4
Cumulative upward adjustment	15.1	$ 15.1		$ 15.1
Number of investments \| investment		1
Additional investment	$ 6.0	$ 5.7	$ 0.0

Equity Securities without Readily Determinable Fair Value, Asset Purchases

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Equity Securities without Readily Determinable Fair Value, Currency Translation On Investments

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Equity Securities without Readily Determinable Fair Value

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Number of investments

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- Definition

Amount of 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 (a)
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117539-209714

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Amount of loss from downward price adjustment on investment in equity security without readily determinable fair value.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117539-209714

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

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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=120269885&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.

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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=120269885&loc=SL75117539-209714

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- Definition

The cash outflow associated with the purchase of all investments (debt, security, other) during the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585

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