Consolidated Statements of Operations - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2021	Sep. 07, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 554.4	$ 1,138.7	$ 1,559.8	$ 1,536.7
Costs and expenses
Cost of services and products, excluding items below	302.1	619.5	802.0	784.6
Selling, general and administrative, excluding items below	115.4	243.4	346.5	354.4
Depreciation and amortization	144.6	194.9	293.4	304.9
Restructuring and severance related charges	0.6	1.2	16.9	6.9
Transaction and integration costs	0.8	54.8	35.0	12.8
Gain on sale of assets, net	0.0	(2.8)	0.0	0.0
Total operating costs and expenses	563.5	1,111.0	1,493.8	1,463.6
Operating (loss) income	(9.1)	27.7	66.0	73.1
Interest expense	28.3	89.1	134.2	139.6
Other components of pension and postretirement benefit plans (benefit) expense	(4.7)	6.4	14.1	11.2
Loss on extinguishment of debt, net	2.1	10.7	0.0	0.0
Other (income) expense, net	(0.3)	19.7	(1.2)	(0.5)
Loss before income taxes	(34.5)	(98.2)	(81.1)	(77.2)
Income tax benefit	(7.3)	(16.9)	(25.5)	(10.6)
Net loss	(27.2)	(81.3)	(55.6)	(66.6)
Preferred stock dividends	0.0	7.6	10.4	10.4
Net loss applicable to common shareowners	$ (27.2)	$ (88.9)	$ (66.0)	$ (77.0)