Consolidated Statements of Shareowners' Equity (Deficit) - USD ($) $ in Millions	Total	Cumulative Convertible Preferred Shares [Member]	Common Shares [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance, Shareowners' Equity (Deficit) at Dec. 31, 2018	$ (75.0)	$ 129.4	$ 0.5	$ 2,680.0	$ (2,709.4)	$ (175.5)
Beginning Balance, Shares at Dec. 31, 2018		3,100,000
Beginning Balance, Shares at Dec. 31, 2018			50,200,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(66.6)				(66.6)
Other comprehensive income	5.4					5.4
Shares issued under employee plans	0.0		$ 0.0	0.0
Shares issued under employee plans, Shares			200,000
Shares purchased under employee plans and other	(0.8)			(0.8)
Stock-based compensation	7.4			7.4
Dividends on preferred stock	(10.4)			(10.4)
Ending Balance, Shareowners' Equity (Deficit) at Dec. 31, 2019	(140.0)	$ 129.4	$ 0.5	2,676.2	(2,776.0)	(170.1)
Ending Balance, Shares at Dec. 31, 2019		3,100,000
Ending Balance, Shares at Dec. 31, 2019			50,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(55.6)				(55.6)
Other comprehensive income	10.4					10.4
Shares issued under employee plans	0.0		$ 0.0	0.0
Shares issued under employee plans, Shares			300,000
Shares purchased under employee plans and other	(1.1)			(1.1)
Stock-based compensation	5.6			5.6
Dividends on preferred stock	(10.4)			(10.4)
Ending Balance, Shareowners' Equity (Deficit) at Dec. 31, 2020	$ (191.1)	$ 129.4	$ 0.5	2,670.3	(2,831.6)	(159.7)
Ending Balance, Shares at Dec. 31, 2020	3,105,000	3,100,000
Ending Balance, Shares at Dec. 31, 2020			50,700,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (81.3)				(81.3)
Other comprehensive income	37.5					37.5
Shares issued under employee plans	0.0		$ 0.0	0.0
Shares issued under employee plans, Shares			200,000
Shares purchased under employee plans and other	(2.0)			(2.0)
Stock-based compensation	4.3			4.3
Equity-based award modification	(10.2)			(10.2)
Dividends on preferred stock	(7.6)			(7.6)
Ending Balance, Shareowners' Equity (Deficit) at Sep. 07, 2021	(250.4)	$ 129.4	$ 0.5	2,654.8	(2,912.9)	(122.2)
Ending Balance, Shares at Sep. 07, 2021		3,100,000
Ending Balance, Shares at Sep. 07, 2021			50,900,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(27.2)
Other comprehensive income	1.2
Ending Balance, Shareowners' Equity (Deficit) at Dec. 31, 2021	1,690.1	$ 0.0	$ 0.0	1,716.1	(27.2)	1.2
Ending Balance, Shares at Dec. 31, 2021		0
Ending Balance, Shares at Dec. 31, 2021			0
Beginning Balance, Shareowners' Equity (Deficit) at Sep. 08, 2021	0.0	$ 0.0	$ 0.0	0.0	0.0	0.0
Beginning Balance, Shares at Sep. 08, 2021		0
Beginning Balance, Shares at Sep. 08, 2021			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(27.2)				(27.2)
Other comprehensive income	1.2					1.2
Capital contributions by Red Fiber Parent LLC	1,716.1			1,716.1
Ending Balance, Shareowners' Equity (Deficit) at Dec. 31, 2021	$ 1,690.1	$ 0.0	$ 0.0	$ 1,716.1	$ (27.2)	$ 1.2
Ending Balance, Shares at Dec. 31, 2021		0
Ending Balance, Shares at Dec. 31, 2021			0