Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations before income taxes	$ (157.5)	$ 7.6	$ (202.7)	$ 8.6
Income tax provision	0.0	2.6	0.0	2.6
(Loss) income from discontinued operations, net of income taxes	(157.5)	$ 5.0	(202.7)	$ 6.0
Other current assets	0.3		0.3		$ 0.3
Investments and other assets	15.9		15.9		16.3
Total assets classified as discontinued operations	16.2		16.2		16.6
Accounts payable and accrued expenses	78.2		78.2		12.5
Other noncurrent liabilities	218.0		218.0		109.8
Total liabilities classified as discontinued operations	296.2		296.2		$ 122.3
Wilkie Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Litigation reserve, amount	7.6		7.6
Wilkie Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Potential cash proceeds from divestiture of asset	$ 20.0		$ 20.0