Acquisitions - SunCoke Lake Terminal LLC (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended								12 Months Ended
	Aug. 30, 2013	Sep. 30, 2013	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Sales and other operating revenue			$ 343.6	$ 336.2	$ 347.6	$ 323.9	$ 384.8	$ 376.2	$ 371.7	$ 358.0	$ 1,351.3	$ 1,490.7	$ 1,633.5
Revenues											1,362.7	1,503.8	1,647.7
Operating (loss) income											79.8	(62.4)	111.3
Coal Logistics Intersegment Sales
Business Acquisition [Line Items]
Sales and other operating revenue											20.4	18.8	5.5
SunCoke Energy Partners, L.P. | SunCoke Lake Terminal LLC [Member]
Business Acquisition [Line Items]
Cash consideration	$ 28.6
Consideration for assigning share of buyout rights to partnership	$ 1.8
Interest acquired (as a percent)	15.00%
Term of contract		10 years
Property and equipment	$ 25.9
Inventory	2.7
Total consideration	$ 28.6
Revenues											14.0	13.4	4.6
Operating (loss) income											3.8	1.7	1.9
SunCoke Energy Partners, L.P. | SunCoke Lake Terminal LLC [Member] | Coal Logistics Intersegment Sales
Business Acquisition [Line Items]
Sales and other operating revenue											$ 13.9	$ 13.1	$ 4.3