Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2019
Entity File Number	001-35243
Entity Registrant Name	SUNCOKE ENERGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-0640593
Entity Address, Address Line One	1011 Warrenville Road
Entity Address, Address Line Two	Suite 600
Entity Address, City or Town	Lisle
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60532
City Area Code	630
Local Phone Number	824-1000
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	SXC
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		86,755,193
Entity Central Index Key	0001514705
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31