Schedule II - Valuation and Qualifying Accounts (Details) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 347.5	$ 462.3	$ 474.1
Charged (Credited) to Costs and Expenses	5.0	4.6	(30.6)
Charged to Other Accounts	16.6	15.8	18.8
Deductions/Write-offs	(11.2)	(135.2)	0.0
Balance at End of Period	357.9	$ 347.5	$ 462.3
Quantenna
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Charged to Other Accounts	$ 14.0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Amount of increase in valuation and qualifying accounts and reserves from charge to accounts other than cost and expense.

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