Environmental (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Environmental remediation costs	$ 7.1	$ 11.2	$ 14.8
Accrued environmental liability	$ 115.0	117.7
Period for environmental remediation (in years)	30 years
Other Noncurrent Liabilities
Loss Contingencies [Line Items]
Accrued environmental liability	$ 94.0	$ 95.6