Business Segment Information - Adjusted EBITDA (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Adjusted EBITDA
Adjusted EBITDA attributable to SunCoke Energy, Inc.	$ 29.8	$ 24.3
Add: Adjusted EBITDA attributable to noncontrolling interests	18.1	9.3
Adjusted EBITDA	47.9sxc_AdjustedEBITDA	33.6sxc_AdjustedEBITDA
Adjusted EBITDA from continuing operations
Adjusted EBITDA from discontinued operations	(3.1)	(4.4)
Legacy income (costs), net	1.9	(1.5)
Adjusted EBITDA from continuing operations	49.1	39.5
Adjustments to EBITDA [Abstract]
Adjustment to unconsolidated affiliate earnings	0.3	1.0
Depreciation and amortization expense	23.8	24.4
Interest expense, net	23.3us-gaap_InterestIncomeExpenseNet	12.1us-gaap_InterestIncomeExpenseNet
Income tax expense (benefit)	1.2us-gaap_IncomeTaxExpenseBenefit	(1.2)us-gaap_IncomeTaxExpenseBenefit
Sales discounts provided to customers due to sharing of nonconventional fuel tax credits	0sxc_SalesDiscount	(0.5)sxc_SalesDiscount
Asset impairment		0us-gaap_AssetImpairmentCharges
Legacy income (costs), net	1.9	(1.5)
Income from continuing operations	2.4	2.2
Loss from discontinued operations, net of tax	(2.0)	(6.0)
Net income (loss)	0.4us-gaap_ProfitLoss	(3.8)us-gaap_ProfitLoss
Accrued sales discounts			13.6
Settlement of accrued sales discounts		13.1
Gain on settlement of accrued sales discounts		$ 0.5

Accrual for sales volume discounts payable current.

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Adjusted EBITDA

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Adjusted EBITDA, Continuing Operations, Legacy Expense, Net

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Adjusted EBITDA, Excluding Portion Attributable to Noncontrolling Interests

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Adjusted EBITDA from Continuing Operations

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Adjusted EBITDA Income (Loss) from Discontinued Operations

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Adjusted EBITDA, Portion Attributable to Noncontrolling Interests

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Adjustment to Income (Loss) from Equity Method Investments

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Gain (Loss) on Payment of Accrual for Sales Volume Discount Payable Current

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Payment of Accrual for Sale Volume Discount Payable Current

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Sales discount.

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The net amount of operating interest income (expense).

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The other noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of tangible and intangible assets over their remaining economic lives.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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