Discontinued Operations - Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
	Apr. 01, 2017	Jun. 30, 2017	Apr. 01, 2017	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2016
Liabilities:
Liabilities subject to compromise	$ 8,416.7		$ 8,416.7			$ 8,440.2
Successor
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of income taxes		$ (2.7)
Liabilities:
Liabilities subject to compromise		0.0
Predecessor
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of income taxes	$ (12.1)		$ (16.2)	$ (3.0)	$ (6.4)
Liabilities:
Liabilities subject to compromise						8,440.2
Discontinued Operations, Held-for-sale or Disposed of by Sale | Successor
Assets:
Other current assets		0.2
Investments and other assets		0.0
Total assets classified as discontinued operations		0.2
Liabilities:
Accounts payable and accrued expenses		55.8
Other noncurrent liabilities		184.9
Liabilities subject to compromise		0.0
Total liabilities classified as discontinued operations		$ 240.7
Discontinued Operations, Held-for-sale or Disposed of by Sale | Predecessor
Assets:
Other current assets						0.2
Investments and other assets						15.9
Total assets classified as discontinued operations						16.1
Liabilities:
Accounts payable and accrued expenses						55.9
Other noncurrent liabilities						198.5
Liabilities subject to compromise						20.9
Total liabilities classified as discontinued operations						$ 275.3