v3.20.2

Guarantees and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Nov. 06, 2020
Contingencies
Insurance	$ (6.2)		$ 1.0	$ (6.2)	$ 1.0
Insurance Recoveries				31.0
Minimum | Scenario, Plan [Member]
Contingencies
Estimated additional insurance recoveries related to business interruption losses and property losses							$ 10.0
Maximum | Scenario, Plan [Member]
Contingencies
Estimated additional insurance recoveries related to business interruption losses and property losses							$ 11.0
Cadillac Project
Contingencies
Estimate damages claimed for statutory misrepresentation	1.0			1.0
Business interruption loss period						45 days
Business interruption expected revenue loss						$ 1.4
Impairment					25.0
Write-down of capital spares		$ 0.6	0.3
Insurance receivable	0.0	$ 24.8	$ 24.2	0.0	24.2	24.8
Insurance					$ 1.0
Insurance Recoveries	7.0			$ 19.7		$ 11.3
Gain on business interruption insurance recovery	6.2
Gain on Business Interruption Insurance Recovery	$ 6.2

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