Consolidated Statements of Cash Flows Supplemental Noncash Investing Activities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Noncash or Part Noncash Acquisition, Investments Acquired	$ 12.1	$ 9.1	$ 16.8
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0.0	12.0	0.0
NoncashOrPartNoncashAcquisitionUnsettledSecurities	0.0	5.3	0.0
Noncash or Part Noncash Acquisitions [Line Items]
Noncash or Part Noncash Acquisition, Investments Acquired	12.1	9.1	16.8
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0.0	12.0	0.0
NoncashOrPartNoncashAcquisitionUnsettledSecurities	0.0	5.3	0.0
Property, Plant and Equipment
Noncash or Part Noncash Acquisitions [Line Items]
Accrued Liabilities	$ 0.0	$ 0.8	$ 0.0