CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income (loss)	$ (340.3)	$ (72.7)
Depreciation	111.1	97.2
Amortization	12.5	10.8
Impairment of Magnetation investment	256.3	0.0
Deferred income taxes	20.7	2.5
Pension and OPEB expense (income)	(32.2)	(50.7)
Contributions to pension trust	(1.0)	(112.4)
Other postretirement benefit payments	(22.2)	(34.7)
Other operating items, net	26.4	(3.5)
Net cash flows from operating activities	83.9	(331.1)
Cash flows from investing activities:
Capital investments	(49.7)	(27.6)
Investments in Magnetation joint venture	0.0	(45.0)
Proceeds from sale of equity investee	25.0	0.0
Other investing items, net	1.3	6.9
Net cash flows from investing activities	(23.4)	(65.7)
Cash flows from financing activities:
Net borrowings (payments) under credit facility	(10.0)	440.0
Redemption of long-term debt	(2.2)	(0.4)
Debt issuance costs	0.0	(3.3)
SunCoke Middletown distributions to noncontrolling interest owners	(42.6)	(28.9)
Other financing items, net	(0.9)	(1.1)
Net cash flows from financing activities	(55.7)	406.3
Net increase (decrease) in cash and cash equivalents	4.8	9.5
Cash and cash equivalents, beginning of period	70.2	45.3
Cash and cash equivalents, end of period	75.0	54.8
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Cash flows from operating activities:
Depreciation	103.9	90.1
Changes in working capital	43.5	(162.4)
Cash flows from investing activities:
Capital investments	(48.9)	(27.3)
Variable Interest Entity, Primary Beneficiary [Member] | SunCoke Middletown [Member]
Cash flows from operating activities:
Depreciation	7.2	7.1
Changes in working capital	9.1	(5.2)
Net cash flows from operating activities	46.1	32.6
Cash flows from investing activities:
Capital investments	(0.8)	(0.3)
Cash flows from financing activities:
SunCoke Middletown distributions to noncontrolling interest owners	(42.6)	$ (28.9)
Cash and cash equivalents, beginning of period	18.2
Cash and cash equivalents, end of period	$ 21.0