CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 65.7	$ 227.0
Accounts receivable, net	536.6	473.9
Inventory, net	684.6	609.2
Deferred tax assets, current	70.8	73.2
Other current assets	44.8	59.4
Total current assets	1,402.5	1,442.7
Property, plant and equipment	5,974.0	5,943.9
Accumulated depreciation	(4,068.3)	(3,931.6)
Property, plant and equipment, net	1,905.7	2,012.3
Other non-current assets:
Investment in AFSG Holdings, Inc.	55.6	55.6
Investment in Magnetation LLC	190.4	150.0
Goodwill	37.1	37.1
Deferred tax assets, non-current	79.6	88.2
Other non-current assets	95.5	117.2
TOTAL ASSETS	3,766.4	3,903.1
Current liabilities:
Short-term borrowings under credit facility	185.0	0
Accounts payable	563.9	538.3
Accrued liabilities	179.1	164.8
Current portion of long-term debt	0.7	0.7
Current portion of pension and other postretirement benefit obligations	78.9	108.6
Total current liabilities	1,007.6	812.4
Non-current liabilities:
Long-term debt	1,415.4	1,411.2
Pension and other postretirement benefit obligations	1,447.1	1,661.7
Other non-current liabilities	108.1	108.8
TOTAL LIABILITIES	3,978.2	3,994.1
Equity (deficit):
Common stock, authorized 200,000,000 shares of $.01 par value each; issued 149,651,303 and 149,094,571 shares in 2013 and 2012; outstanding 136,341,621 and 135,944,172 shares in 2013 and 2012	1.5	1.5
Additional paid-in capital	2,077.1	2,069.7
Treasury stock, common shares at cost, 13,309,682 and 13,150,399 shares in 2013 and 2012	(174.0)	(173.3)
Accumulated deficit	(2,486.3)	(2,404.3)
Accumulated other comprehensive income (loss)	(50.9)	1.1
Total stockholders' equity (deficit)	(632.6)	(505.3)
Noncontrolling interests	420.8	414.3
TOTAL EQUITY (DEFICIT)	(211.8)	(91.0)
TOTAL LIABILITIES AND EQUITY (DEFICIT)	3,766.4	3,903.1
Variable Interest Entity, Primary Beneficiary [Member] | SunCoke Middletown [Member]
Current assets:
Cash and cash equivalents	13.4	0
Accounts receivable, net	0.5	1.0
Inventory, net	23.3	28.3
Property, plant and equipment	417.6	414.5
Accumulated depreciation	(25.5)	(15.0)
Other assets (liabilities), net	0.1	(1.2)
Current liabilities:
Accounts payable	10.5	15.4
Equity (deficit):
Noncontrolling interests	418.9	412.2
Variable Interest Entity, Primary Beneficiary [Member] | Other Variable Interest Entities [Member]
Current assets:
Cash and cash equivalents	0.8	1.2
Property, plant and equipment	11.5	11.4
Accumulated depreciation	(9.1)	(8.9)
Other assets (liabilities), net	0.6	0.6
Equity (deficit):
Noncontrolling interests	$ 1.9	$ 2.1