Supplemental Financial Data - Other Income (Expense) - Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 18, 2022	Dec. 20, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Non-operating pension income (expense)	$ 18.3	$ 42.2	$ 53.7
Debt redemption premium	0.0	(16.3)	(29.5)
Miscellaneous other income (expense) – net	(23.6)	(12.0)	(9.3)
Other income (expense) – net	$ (5.3)	$ 13.9	$ 14.9
6.875% Senior Secured Notes Due 2026 | Secured Debt
Valuation Allowance [Line Items]
Interest rate on debt instrument (as a percent)		6.875%		6.875%
10.250% Senior Unsecured Notes Due 2027 | Unsecured Debt
Valuation Allowance [Line Items]
Interest rate on debt instrument (as a percent)			10.25%		10.25%