Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Supplemental cash flow, net cash paid (received) during the period for: [Abstract]
Interest, net of capitalized interest	$ 31.2	$ 21.0
Income taxes paid, net	0.8	(0.5)
Net Cash Provided by (Used in) Operating Activities	(387.9)	(355.4)
Proceeds from borrowings under the credit facility classified as long-term	400.0
Repayments of borrowings under the credit facility classified as short-term	(208.0)
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Supplemental cash flow, noncash investing and financing activities [Abstract]
Capital investments	9.2	9.0
SunCoke Middletown [Member]
Supplemental cash flow, net cash paid (received) during the period for: [Abstract]
Net Cash Provided by (Used in) Operating Activities	12.0	(17.1)
Supplemental cash flow, noncash investing and financing activities [Abstract]
Capital investments	0	23.3
Restricted Stock and Restricted Stock Units [Member]
Supplemental cash flow, noncash investing and financing activities [Abstract]
Issuance of restricted stock and restricted stock units	$ 5.2	$ 5.6

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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The amount of cash paid for interest during the period net of cash paid for interest that is capitalized.

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- Definition

The net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities generally involve producing and delivering goods and providing services. Operating activity cash flows include transactions, adjustments, and changes in value that are not defined as investing or financing activities. While for technical reasons this element has no balance attribute, the default assumption is a debit balance consistent with its label.

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- Definition

The cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

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- Definition

The cash outflow to pay off an obligation from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity.

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