Supplemental Balance Sheet Information - Accounts Receivable (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts receivable	$ 186.5	$ 186.5	$ 166.8
Accounts receivable, net	182.3	182.3	163.8
Other receivables	69.7	69.7	14.3
Provision for doubtful accounts	0.3	1.2
Doubtful accounts
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances and doubtful accounts	(3.9)	(3.9)	(2.7)
Sales discounts
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowances and doubtful accounts	$ (0.3)	$ (0.3)	$ (0.3)