Retirement and Other Postretirement Benefit Plans - Schedule of Amounts Recognized on Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Amounts recognized on the balance sheet:
Other non-current liabilities	$ 52.4	$ 53.9
Defined Benefit Retirement Plans | U.S.
Amounts recognized on the balance sheet:
Accrued liabilities	3.8	3.8
Other non-current liabilities	19.7	19.4
Total accrued benefit	$ 23.5	$ 23.2
Defined Benefit Plan, Tax Status [Extensible List]	Non-qualified	Non-qualified	Non-qualified
Defined Benefit Retirement Plans | European
Amounts recognized on the balance sheet:
Other assets	$ 34.8	$ 31.5
Accrued liabilities	1.6	0.9
Other non-current liabilities	19.1	17.7
Total accrued benefit	20.6	18.6
Postretirement Health Care and Life Insurance Benefit Plans
Amounts recognized on the balance sheet:
Accrued liabilities	0.4	0.4
Other non-current liabilities	2.2	2.2
Total accrued benefit	$ 2.6	$ 2.6