Partnership Initial Public Offering and Dropdown Transactions - Haverhill and Middletown Dropdown (Details) - USD ($) shares in Millions					3 Months Ended	12 Months Ended
	Aug. 12, 2015	Jan. 13, 2015	May. 09, 2014	Jan. 23, 2013	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	May. 08, 2014
Business Acquisition [Line Items]
Ownership interest of general partnership (as a percent)						2.00%
Interest in partnership (as a percent)	53.40%	56.10%	54.10%			53.90%			55.90%
Ownership percentage held by public unitholders	44.60%	41.90%	43.90%			44.10%
Long-term Debt						$ 998,800,000	$ 633,500,000
Proceeds from issuance of common units of SunCoke Energy Partners, L.P., net of offering costs						0	90,500,000	$ 237,800,000
Increase in SunCoke Energy, Inc. equity for the contribution of 33 percent interest in Haverhill and Middletown						12,800,000
Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Interest acquired (as a percent)			33.00%
Increase in SunCoke Energy, Inc. equity for the contribution of 33 percent interest in Haverhill and Middletown					$ 83,700,000	$ 0	83,700,000
SunCoke Energy Partners, L.P. | Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Interest acquired (as a percent)			33.00%
Fair value of total consideration transferred			$ 365,000,000
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			10,400,000
Redemption Premium			11,400,000
Business Acquisition, Consideration Transferred, Cash			3,400,000
Consideration withheld to pre-fund anticipated environmental remediation costs			7,000,000
Proceeds from issuance of private placement			$ 263,100,000
IPO | General Partner
Business Acquisition [Line Items]
Ownership interest of general partnership (as a percent)				2.00%
Common units | SunCoke Energy Partners, L.P.
Business Acquisition [Line Items]
Proceeds from issuance of private placement							$ 1,800,000
Common units | SunCoke Energy Partners, L.P. | Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares			2.7
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			$ 80,000,000
Stock issued (in shares)			3.2
Proceeds from issuance of common units of SunCoke Energy Partners, L.P., net of offering costs			$ 88,700,000
General Partner | SunCoke Energy Partners, L.P. | Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			3,300,000
Term Loans | SunCoke Energy Partners, L.P. | Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Long-term Debt			271,300,000
7.375% Partnership notes, due 2020
Business Acquisition [Line Items]
Interest rate (as a percent)						7.375%	7.375%
7.375% Partnership notes, due 2020 | Haverhill Coke Company LLC and Middletown Coke Company LLC
Business Acquisition [Line Items]
Proceeds to fund interest			5,000,000
7.375% Partnership notes, due 2020 | SunCoke Energy Partners, L.P.
Business Acquisition [Line Items]
Long-term Debt			$ 250,000,000
Interest rate (as a percent)			7.375%