CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
REVENUES	$ 1,843.2	$ 2,137.0	$ 1,824.4
COSTS AND EXPENSES:
Direct operating costs (excluding items below)	778.2	993.1	991.3
Depreciation and amortization	402.9	391.4	322.6
Selling, general and administrative	102.1	115.8	125.8
(Gain) loss on disposals of property and equipment	8.7	(7.7)	(1.7)
Gain on litigation settlement	0.0	0.0	(20.9)
Material charges and other operating items	32.9	337.3	574.0
Total costs and expenses	1,324.8	1,829.9	1,991.1
INCOME (LOSS) FROM OPERATIONS	518.4	307.1	(166.7)
OTHER INCOME (EXPENSE):
Interest expense, net of interest capitalized	(155.5)	(145.3)	(103.9)
Interest income	3.8	1.1	1.8
Loss on debt extinguishment	(31.2)	(1.5)	0.0
Other - net	(9.9)	(3.7)	(0.8)
Total other (expense) - net	(192.8)	(149.4)	(102.9)
INCOME (LOSS) FROM CONTINUING OPERATIONS
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	325.6	157.7	(269.6)
Provision (benefit) for income taxes	5.0	64.4	(150.7)
INCOME (LOSS) FROM CONTINUING OPERATIONS	320.6	93.3	(118.9)
DISCONTINUED OPERATIONS, NET OF TAX	0.0	0.0	4.0
NET INCOME (LOSS)	$ 320.6	$ 93.3	$ (114.9)
INCOME (LOSS) PER SHARE - BASIC:
Income (loss) from continuing operations (in dollars per share)	$ 2.56	$ 0.75	$ (0.96)
Discontinued operations (in dollars per share)	0.00	0.00	0.03
Net income (loss) (in dollars per share)	2.56	0.75	(0.93)
INCOME (LOSS) PER SHARE - DILUTED:
Income (loss) from continuing operations (in dollars per share)	2.55	0.75	(0.96)
Discontinued operations (in dollars per share)	0.00	0.00	0.03
Net income (loss) (in dollars per share)	$ 2.55	$ 0.75	$ (0.93)