Basis of Presentation Basis of Presentation text (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Apr. 13, 2016	Dec. 31, 2015
Income Tax Expense (Benefit)	$ 2.2	$ (59.8)
Stock Warrants Issued	2.9
Common Stock, Value, Issued	137.3
Total Consideration for Prepetition Indebtedness	704.0
Successor Notes	1,000.0
Letters of Credit Outstanding, Amount	167.2
Loss from continuing operations, net of income taxes	124.3	(167.7)
Net income (loss)	120.2	(171.1)
Net Income (Loss) Attributable to Common Stockholder	$ 115.4	$ (171.1)
Loss from continuing operations	$ 6.46	$ (9.17)
Earnings Per Share, Basic	6.24	(9.35)
Income (Loss) from Continuing Operations, Per Diluted Share	6.44	(9.17)
Earnings Per Share, Diluted	$ 6.21	$ (9.35)
6.000% Senior Secured Notes Due 2022 [Member]
Debt Instrument, Face Amount			$ 500.0
Stated interest rate - percentage			6.00%
6.375% Senior Secured Notes Due 2025 [Member]
Stated interest rate - percentage			6.375%
Successor Notes [Domain]
Debt Issuance Cost	$ 49.5
Term Loan Facility [Member]
Stated interest rate - percentage			4.50%
Line of Credit Facility, Maximum Borrowing Capacity			$ 950.0
Term Loan Facility [Member] | Eurocurrency Rate [Member]
Floor interest rate			1.00%
10.00% Senior Secured Second Lien Notes Due 2022 [Member]
Stated interest rate - percentage			10.00%
Debt Instrument, Outstanding Principal			$ 1,000.0
Long-term debt	$ 962.3		$ 962.3
6.50% Senior Notes due September 2020 [Member]
Stated interest rate - percentage	6.50%		6.50%
Debt Instrument, Outstanding Principal			$ 650.0
Long-term debt	$ 645.8		$ 645.8
6.00% Senior Notes due November 2018 [Member]
Stated interest rate - percentage	6.00%		6.00%
Debt Instrument, Outstanding Principal			$ 1,518.8
Long-term debt	$ 1,509.9		$ 1,509.9
6.25% Senior Notes due November 2021 [Member]
Stated interest rate - percentage	6.25%		6.25%
Debt Instrument, Outstanding Principal			$ 1,339.6
Long-term debt	$ 1,327.7		$ 1,327.7
7.875% Senior Notes due November 2026 [Member]
Stated interest rate - percentage	7.875%		7.875%
Debt Instrument, Outstanding Principal			$ 250.0
Long-term debt	$ 245.9		245.9
Convertible Junior Subordinated Debentures due December 2066 [Member]
Debt Instrument, Outstanding Principal			732.5
Long-term debt	367.1		367.1
2013 Term Loan Facility due September 2020 [Member]
Debt Instrument, Outstanding Principal			1,170.0
Long-term debt	1,154.5		1,154.5
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity			1,650.0
Letters of Credit Outstanding, Amount				$ 675.0
Long-term debt	1,555.2	$ 947.0	1,558.1
Backstop Commitment Agreement [Domain]
Common Stock, Value, Issued	3.3
Private Placement [Member]
Common Stock, Value, Issued	4.8
Warrant Agreement [Domain]
Common Stock, Value, Issued	6.2
Common Stock [Member]
Common Stock, Value, Issued	$ 0.2		$ 0.2
Common Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01		$ 0.01
Class 2A, 2B, 2C and 5B [Domain]
Common Stock, Value, Issued	$ 11.6
Rights Offering [Domain]
Common Stock, Value, Issued	$ 51.2
Private Placement Agreement [Domain]
Preferred Stock, Shares Authorized	30.0
Unvested Emergence RSU's [Domain]
Common Stock, Value, Issued	$ 3.6
Backstop Commitment Agreement [Member]
Total Consideration for Prepetition Indebtedness	46.0
Private Placement Agreement [Domain]
Total Consideration for Prepetition Indebtedness	750.0
Private Placement Agreement [Member]
Stock Warrants Issued	3.1
Noteholder Co-Proponents [Member]
Stock Warrants Issued	6.2
Backstop Commitment Agreement [Member]
Stock Warrants Issued	0.2
Class 2A, 2B, 2C and 5B [Domain]
Common Stock, Value, Issued	0.0
Scenario, Previously Reported [Member]
Income Tax Expense (Benefit)	(4.5)	(65.8)
Loss from continuing operations, net of income taxes	131.0	(161.7)
Net income (loss)	126.9	(165.1)
Net Income (Loss) Attributable to Common Stockholder	$ 122.1	$ (165.1)
Loss from continuing operations	$ 6.82	$ (8.85)
Earnings Per Share, Basic	6.60	(9.03)
Income (Loss) from Continuing Operations, Per Diluted Share	6.80	(8.85)
Earnings Per Share, Diluted	$ 6.57	$ (9.03)
Capital Units [Member]
Common Stock, Value, Issued	$ 54.5
Incorrect Use of Deferred Tax Liabilities in Assessment of Valuation Allowances in 2013
Deferred Income Tax Liabilities, Net	$ 163.0		$ 156.3