Commitments and Contingencies Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Pre-tax restructuring costs			$ 32.0	$ 12.0	$ 20.3
Settlement of multi-employer pension plan	$ 10.0
Total environmental liabilities	$ 8.0		8.0	$ 8.5
Withdrawal from Multiemployer Defined Benefit Plan
Loss Contingencies [Line Items]
Pre-tax restructuring costs		$ 12.5	$ 8.5