Statements of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities:
Net loss	$ (109.1)	$ (53.5)	$ (104.0)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation and amortization	143.6	134.9	152.4
Lease amortization and accretion expense	133.3	160.9	168.0
Lease payments	(134.4)	(135.0)	(155.1)
Paid-in-kind interest	9.3	42.4	0.0
Debt-related amortization	22.9	17.5	6.7
Equity-based compensation and employee benefits expense	16.1	21.8	18.6
Non-union pension settlement charges	64.7	3.6	1.8
(Gains) losses on property disposals, net	0.7	(45.3)	(13.7)
Loss on extinguishment of debt	0.0	0.0	11.2
Impairment charges	0.0	0.0	8.2
Deferred income taxes, net	(0.5)	(14.9)	(3.0)
Other noncash items, net	0.7	0.9	(0.3)
Changes in assets and liabilities, net:
Accounts receivable	(158.7)	(40.4)	7.1
Accounts payable	16.8	(3.6)	(14.8)
Other operating assets	(28.1)	(23.9)	(1.5)
Other operating liabilities	32.9	57.1	(60.1)
Net cash provided by (used in) operating activities	10.2	122.5	21.5
Investing Activities:
Acquisition of property and equipment	(497.6)	(140.6)	(143.2)
Proceeds from disposal of property and equipment	3.6	56.1	25.9
Net cash provided by (used in) investing activities	(494.0)	(84.5)	(117.3)
Financing Activities:
Issuance of long-term debt, net	325.2	374.8	570.0
Repayment of long-term debt	(3.8)	(31.4)	(579.0)
Debt issuance costs	(0.2)	(12.0)	(12.7)
Payments for tax withheld on equity-based compensation	(0.6)	(0.6)	(0.9)
Net cash provided by (used in) financing activities	320.6	330.8	(22.6)
Net Increase (Decrease) In Cash and Cash Equivalents and Restricted Amounts Held in Escrow	(163.2)	368.8	(118.4)
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, Beginning of Year	478.0	109.2	227.6
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, End of Year	314.8	478.0	109.2
Supplemental Cash Flow Information:
Interest paid	$ (116.8)	$ (67.6)	$ (106.8)