Discontinued Operations (Narrative) (Details) $ / shares in Units, $ in Millions		6 Months Ended	12 Months Ended	37 Months Ended
	Aug. 07, 2018 USD ($) shares	Dec. 31, 2018 USD ($)	Dec. 31, 2018 shares	Dec. 31, 2020 USD ($)	Sep. 30, 2018 USD ($)	Aug. 03, 2018 $ / shares
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Distribution of shares outstanding to shareholders, conversion ratio			1.980295
Separation Expense				$ 34.2
Transition services benefit		$ 6.3
Arlo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shares, outstanding (in shares) | shares	74,247,000
Arlo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shares, outstanding (in shares) | shares	62,500,000
Ownership percentage	84.20%
Number of shares distributed (in shares) | shares			62,500,000
Cash consideration					$ 70.0
IPO | Arlo
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of stock, price per share (USD per share) | $ / shares						$ 16.00
Sale of stock, consideration received	$ 170.2