CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income (loss)	$ (34.4)	$ (777.0)
Depreciation	144.9	144.9
Amortization	15.1	12.8
Deferred income taxes	11.0	753.4
Pension and OPEB expense (income)	(49.3)	(28.0)
Contributions to pension trust	(140.2)	(170.2)
Other postretirement benefit payments	(47.2)	(48.3)
Other operating items, net	(0.1)	3.1
Net cash flows from operating activities	(223.7)	(387.9)
Cash flows from investing activities:
Capital investments	(48.1)	(49.3)
Investments in acquired businesses	(50.0)	(38.1)
Other investing items, net	15.1	4.6
Net cash flows from investing activities	(83.0)	(82.8)
Cash flows from financing activities:
Net borrowings under credit facility	185.0	192.0
Proceeds from issuance of long-term debt	31.9	373.3
Redemption of long-term debt	(27.2)	(73.9)
Debt issuance costs	(3.1)	(8.6)
Purchase of treasury stock	(0.7)	(1.7)
Common stock dividends paid	0	(11.0)
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	(41.1)	5.5
Other financing items, net	0.6	0.2
Net cash flows from financing activities	145.4	475.8
Net increase (decrease) in cash and cash equivalents	(161.3)	5.1
Cash and cash equivalents, beginning of period	227.0	42.0
Cash and cash equivalents, end of period	65.7	47.1
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Cash flows from operating activities:
Depreciation	134.4	134.7
Changes in working capital	(91.7)	(217.1)
Cash flows from investing activities:
Capital investments	(45.3)	(31.8)
SunCoke Middletown [Member]
Cash flows from operating activities:
Depreciation	10.5	10.2
Changes in working capital	(1.0)	(29.8)
Cash flows from investing activities:
Capital investments	(2.8)	(17.5)
Cash flows from financing activities:
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	(41.1)	5.5
Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]
Cash flows from operating activities:
Contributions to Butler and Zanesville retirees VEBAs	$ (30.8)	$ (31.7)