VARIABLE INTEREST ENTITIES (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Variable Interest Entity [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest	$ 15.8	$ 0.0	$ 19.3	$ 0.0
Cash and cash equivalents	73.7		73.7		$ 352.6
Inventories	1,933.6		1,933.6		317.4
Property, plant and equipment, net	4,547.9		4,547.9		1,929.0
Accounts payable	(504.8)		(504.8)		(193.2)
Noncontrolling interest	(325.3)		(325.3)		$ 0.0
SunCoke Middletown [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net Income (Loss) Attributable to Noncontrolling Interest	16.0		19.5
Cash and cash equivalents	1.0		1.0
Inventories	21.2		21.2
Property, plant and equipment, net	309.2		309.2
Accounts payable	(5.6)		(5.6)
Other Assets (Liabilities), Net	(1.2)		(1.2)
Noncontrolling interest	$ (324.6)		$ (324.6)

Other Assets (Liabilities), Net

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Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

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Amount of Net Income (Loss) attributable to noncontrolling interest.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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