Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Deficit	Total SunCoke Energy, Inc. Equity	Noncontrolling Interests
Acquisition of additional interest in the Partnership:
Cumulative effect from adoption of ASU 2016-09				$ 0.3		$ (0.3)
Beginning balance, shares at Dec. 31, 2016		71,707,304	7,477,657
Beginning balance at Dec. 31, 2016	$ 639.9	$ 0.7	$ (140.7)	492.1	$ (19.0)	(22.0)	$ 311.1	$ 328.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(89.2)					(23.2)	(23.2)	(66.0)
Currency translation adjustment	(0.2)				(0.2)		(0.2)
Cash distribution to noncontrolling interests	(24.6)							(24.6)
Share-based compensation expense	3.0			2.9			2.9	0.1
Share issuances, net of shares withheld for taxes, shares		99,771
Share-issuances, net of shares withheld for taxes	(0.3)			(0.3)			(0.3)
Acquisition of additional interest in the Partnership:
Cash paid	(24.6)			(9.2)			(9.2)	(15.4)
Deferred tax adjustment	3.4			3.4			3.4
Ending balance, shares at Jun. 30, 2017		71,807,075	7,477,657
Ending balance at Jun. 30, 2017	$ 507.4	$ 0.7	$ (140.7)	$ 489.2	$ (19.2)	$ (45.5)	$ 284.5	$ 222.9