Statements of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities:
Net income (loss)	$ (104.0)	$ 20.2	$ (10.8)
Adjustments to reconcile net income (loss) to cash flows from operating activities:
Depreciation and amortization	152.4	147.7	147.7
Lease amortization and accretion expense	168.0	0.0	0.0
Lease payments	(155.1)	0.0	0.0
Equity-based compensation and employee benefits expense	18.6	20.3	22.0
Non-union pension settlement charge	1.8	10.9	7.6
Gains on property disposals, net	(13.7)	(20.8)	(0.6)
Loss on extinguishment of debt	11.2	0.0	0.0
Impairment charges	8.2	0.0	0.0
Deferred income tax benefit, net	(3.0)	(1.1)	(13.2)
Other noncash items, net	6.4	4.9	13.2
Changes in assets and liabilities, net:
Accounts receivable	7.1	16.6	(38.6)
Accounts payable	(14.8)	6.1	10.9
Other operating assets	(1.5)	5.4	14.9
Other operating liabilities	(60.1)	14.6	(92.4)
Net cash provided by operating activities	21.5	224.8	60.7
Investing Activities:
Acquisition of property and equipment	(143.2)	(145.4)	(103.3)
Proceeds from disposal of property and equipment	25.9	36.4	8.8
Net cash used in investing activities	(117.3)	(109.0)	(94.5)
Financing Activities:
Issuance of long-term debt, net of discounts	570.0	0.0	0.0
Repayment of long-term debt	(579.0)	(31.9)	(79.3)
Debt issuance costs	(12.7)	0.0	(14.5)
Payments for tax withheld on equity-based compensation	(0.9)	(2.0)	(2.4)
Net cash used in financing activities	(22.6)	(33.9)	(96.2)
Net Increase (Decrease) In Cash and Cash Equivalents and Restricted Amounts Held in Escrow	(118.4)	81.9	(130.0)
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, Beginning of Year	227.6	145.7	275.7
Cash and Cash Equivalents and Restricted Amounts Held in Escrow, End of Year	109.2	227.6	145.7
Supplemental Cash Flow Information:
Interest paid	(106.8)	(101.2)	(103.4)
Letter of credit fees paid	(6.8)	(7.0)	(7.0)
Income tax refund (payment)	$ (3.7)	$ (5.5)	$ 1.7