Liabilities Subject to Compromise (Details) - USD ($)		Mar. 31, 2017	Dec. 31, 2016
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise		$ 8,416,700,000	$ 8,440,200,000
Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise	[1]	8,077,400,000	8,080,300,000
Interest Payable [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise		172,600,000	172,600,000
Accounts Payable [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise		55,200,000	58,400,000
Environmental liabilities
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise		61,900,000	61,900,000
Other Pension, Postretirement and Supplemental Plans [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise	[2]	23,000,000	34,600,000
Accrued Liabilities [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise		26,600,000	32,400,000
Debt [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise	[1]	7,768,300,000	$ 7,771,200,000
Hedge terminations [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise	[1]	257,300,000
Liabilities secured by prepetition letters of credit [Member] | Long-term Debt [Member]
Schedule of liabilities subject to compromise [Line Items]
Liabilities subject to compromise	[1]	$ 51,800,000

[1] Includes $7,768.3 million and $7,771.2 million of first lien, second lien and unsecured debt at March 31, 2017 and December 31, 2016, respectively, and $257.3 million of derivative contract terminations, and $51.8 million of liabilities secured by prepetition letters of credit at March 31, 2017 and December 31, 2016.

[2] Includes liabilities for unfunded non-qualified pension plans, all the participants of which are former employees.