Environmental (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Loss Contingencies [Line Items]
Environmental remediation costs	$ 0.5	$ 2.2	$ 2.5	$ 4.2
Accrued environmental liability	111.9		$ 111.9		$ 115.0
Period for environmental remediation (in years)			30 years
Other Noncurrent Liabilities
Loss Contingencies [Line Items]
Accrued environmental liability	$ 93.2		$ 93.2		$ 94.0