Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Total SunCoke Energy, Inc. Equity	Non-controlling Interests
Beginning balance at Dec. 31, 2012	$ 574.9	$ 0.7	$ (9.4)	$ 436.9	$ (7.9)	$ 118.8	$ 539.1	$ 35.8
Beginning balance, shares at Dec. 31, 2012		70,561,439	603,528
Net income (loss)	50.1					25.0	25.0	25.1
Reclassifications of prior service benefit and actuarial loss amortization to earnings	(1.9)				(1.9)		(1.9)
Retirement benefit plans funded status adjustment (net of related tax benefit (expense) of $0.1 million, $1.6 million and ($3.8 million), respectively)	5.7				5.7		5.7
Currency translation adjustment	(10.0)				(10.0)		(10.0)
Net proceeds from issuance of SunCoke Energy Partners, L.P. units	231.8							231.8
Cash distributions to noncontrolling interests	(17.8)							(17.8)
Share-based compensation expense	7.6			7.6			7.6
Stock issuances	2.8			2.8			2.8
Shares issuances, shares		330,701
Shares repurchased	(10.9)		$ (10.5)	(0.4)			(10.9)
Shares repurchased, shares		0	651,827
Ending balance at Dec. 31, 2013	832.3	$ 0.7	$ (19.9)	446.9	(14.1)	143.8	557.4	274.9
Ending balance, shares at Dec. 31, 2013		70,892,140	1,255,355
Net income (loss)	(101.8)					(126.1)	(126.1)	24.3
Reclassifications of prior service benefit and actuarial loss amortization to earnings	(4.0)				(4.0)		(4.0)
Retirement benefit plans funded status adjustment (net of related tax benefit (expense) of $0.1 million, $1.6 million and ($3.8 million), respectively)	(2.6)				(2.6)		(2.6)
Currency translation adjustment	(0.8)				(0.8)		(0.8)
Net proceeds from issuance of SunCoke Energy Partners, L.P. units	90.5							90.5
Adjustments from changes in ownership of SunCoke Energy Partners, L.P.	0.0			83.7			83.7	(83.7)
Cash distributions to noncontrolling interests	(32.3)							(32.3)
Dividends	(3.8)					(3.8)	(3.8)
Share-based compensation expense	9.8			9.8			9.8
Excess tax benefit from share-based awards	0.3			0.3			0.3
Stock issuances	2.9			2.9			2.9
Shares issuances, shares		359,389
Shares repurchased	$ (85.1)		$ (85.1)				(85.1)
Shares repurchased, shares	3,200,000		3,721,760
Ending balance at Dec. 31, 2014	$ 705.4	$ 0.7	$ (105.0)	543.6	(21.5)	13.9	431.7	273.7
Ending balance, shares at Dec. 31, 2014		71,251,529	4,977,115
Net income (loss)	10.3					(22.0)	(22.0)	32.3
Reclassifications of prior service benefit and actuarial loss amortization to earnings	5.2				5.2		5.2
Retirement benefit plans funded status adjustment (net of related tax benefit (expense) of $0.1 million, $1.6 million and ($3.8 million), respectively)	(0.4)				(0.4)		(0.4)
Currency translation adjustment	(3.1)				(3.1)		(3.1)
Adjustments from changes in ownership of SunCoke Energy Partners, L.P.	75.0			(8.0)			(8.0)	83.0
Deferred taxes related to basis difference in the Partnership	(55.6)			(55.6)			(55.6)
Cash distributions to noncontrolling interests	(43.3)							(43.3)
Dividends	(28.3)					(28.3)	(28.3)
Share-based compensation expense	7.2			7.2			7.2
Stock issuances	(1.1)			(1.1)			(1.1)
Shares issuances, shares		237,919
Shares repurchased	$ (35.7)		$ (35.7)				(35.7)
Shares repurchased, shares	2,500,000		2,500,542
Partnership unit repurchases	$ (12.8)							(12.8)
Ending balance at Dec. 31, 2015	$ 622.8	$ 0.7	$ (140.7)	$ 486.1	$ (19.8)	$ (36.4)	$ 289.9	$ 332.9
Ending balance, shares at Dec. 31, 2015		71,489,448	7,477,657