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v3.21.2

Other Expense, Net (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Other Income And Expenses [Abstract] |  |  |  |
Interest income | $ 0.1 | $ 0.2 | $ 0.2 | $ 0.5
Net periodic postretirement benefit cost | (1.2) | (1.1) | (3.0) | (3.5)
Realized gain on available for sale securities |  |  |  | 2.1
Unrealized gain on equity securities |  | 0.3 |  | 0.4
Gain (loss) on extinguishment of debt |  |  | (35.9) |
All other, net | (0.1) | 0.1 | 0.5 | (0.3)
Other expense, net | $ (1.2) | $ (0.5) | $ (38.2) | $ (0.8)

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- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
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