Description of Business and Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2021	Sep. 07, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash and cash equivalents	$ 5.6		$ 12.2	$ 11.6
Restricted cash included in Other noncurrent assets	0.5		5.0	0.0
Cash, cash equivalents and restricted cash per Consolidated Statements of Cash Flows	$ 6.1	$ 11.2	$ 17.2	$ 11.6	$ 15.4