Statement of Consolidated Shareholders' Deficit - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Capital Surplus	Accumulated Deficit	Accumulated Other Comprehensive Loss	Treasury Stock, At Cost
Beginning balance at Dec. 31, 2017	$ (353.5)	$ 0.0	$ 0.3	$ 2,323.3	$ (2,228.6)	$ (355.8)	$ (92.7)
Equity-based compensation	4.3	0.0		4.3
Net income (loss)	20.2				20.2
Amortization of prior net losses	14.6	0.0				14.6
Amortization of prior net service credit	(0.4)	0.0				(0.4)
Settlement adjustment	10.9					10.9
Net actuarial gain (loss)	1.0					1.0
Changes in foreign currency translation	(2.6)					(2.6)
Ending balance at Dec. 31, 2018	(305.5)	0.0	0.3	2,327.6	(2,208.4)	(332.3)	(92.7)
Equity-based compensation	5.3	0.0		5.3
Net income (loss)	(104.0)	0.0			(104.0)
Amortization of prior net losses	12.9	0.0				12.9
Amortization of prior net service credit	(0.4)	0.0				(0.4)
Settlement adjustment	1.8	0.0				1.8
Net actuarial gain (loss)	(51.7)					(51.7)
Changes in foreign currency translation	0.4					0.4
Ending balance at Dec. 31, 2019	(441.2)	0.0	0.3	2,332.9	(2,312.4)	(369.3)	(92.7)
Equity-based compensation	4.2	0.0		4.2
Equity issuance - UST commitment fee	46.7		0.2	46.5
Net income (loss)	(53.5)	0.0			(53.5)
Amortization of prior net losses	12.7	0.0				12.7
Amortization of prior net service credit	(0.4)	0.0				(0.4)
Settlement adjustment	2.7	0.0				2.7
Net actuarial gain (loss)	204.6					204.6
Changes in foreign currency translation	0.9					0.9
Ending balance at Dec. 31, 2020	$ (223.3)	$ 0.0	$ 0.5	$ 2,383.6	$ (2,365.9)	$ (148.8)	$ (92.7)