Fresh Start Accounting - Successor Assets To Be Allocated (Details) - USD ($) $ in Millions	Sep. 30, 2023	Aug. 12, 2023	Aug. 11, 2023	Dec. 31, 2022
Reorganizations [Abstract]
Enterprise value			$ 2,150.0
Plus: Excess cash available for operations			206.1
Less: Net pension, post-retirement and other benefits liability			(39.3)
Noncontrolling interests	$ 14.8	$ 13.9	13.9	$ 9.8
Plus: Fair value of non-debt current liabilities			1,398.3
Plus: Fair value of non-debt, non-current liabilities			225.0
Deferred income taxes	166.2	238.5	238.5	96.6
Total assets	$ 4,019.6	$ 4,178.6	$ 4,178.6	$ 3,065.0