Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 33.3	$ 8.5	$ 77.7	$ 48.2
Other comprehensive income (loss):
Reclassifications of prior service benefit and actuarial loss amortization to earnings, net of tax	0.1	0.0	0.2	0.1
Currency translation adjustment	0.0	(0.3)	(0.9)	0.2
Comprehensive income	33.4	8.2	77.0	48.5
Less: Comprehensive income attributable to noncontrolling interests	2.6	1.5	5.5	4.5
Comprehensive income attributable to SunCoke Energy, Inc.	$ 30.8	$ 6.7	$ 71.5	$ 44.0