Ak Steel Holding (AKS) 10-Q 26 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2018	Oct. 24, 2018
Document Information [Line Items]
Entity Registrant Name	AK STEEL HOLDING CORPORATION
Entity Central Index Key	918,160
Trading Symbol	AKS
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		315,541,965

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net sales	$ 1,735.6	$ 1,494.3	$ 5,141.1	$ 4,584.9
Cost of products sold (exclusive of item shown separately below)	1,486.2	1,301.8	4,462.6	3,898.7
Selling and administrative expenses	79.6	68.2	235.8	205.5
Depreciation	55	58	164.8	168.2
Total operating costs	1,620.8	1,428	4,863.2	4,272.4
Operating profit	114.8	66.3	277.9	312.5
Interest expense	37.8	37.5	113.3	115.1
Pension and OPEB (income) expense	(10)	(18.1)	(30)	(54.3)
Other (income) expense	0.7	7.8	(3.4)	19.2
Income before income taxes	86.3	39.1	198	232.5
Income tax expense (benefit)	1.4	(0.3)	(4)	0.1
Net income	84.9	39.4	202	232.4
Less: Net income attributable to noncontrolling interests	17.7	17.1	49.5	48.5
Net income attributable to AK Steel Holding Corporation	$ 67.2	$ 22.3	$ 152.5	$ 183.9
Net income per share attributable to AK Steel Holding Corporation common stockholders:
Basic	$ 0.21	$ 0.07	$ 0.48	$ 0.58
Diluted	$ 0.21	$ 0.07	$ 0.48	$ 0.57

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income	$ 84.9	$ 39.4	$ 202	$ 232.4
Other comprehensive income (loss), before tax:
Foreign currency translation gain (loss)	(0.3)	1.4	(1.4)	4
Cash flow hedges:
Gains (losses) arising in period	(2.3)	7.3	(7.8)	(8.9)
Reclassification of losses (gains) to net income	0.5	(0.2)	(12.6)	(2.1)
Pension and OPEB plans:
Reclassification of prior service cost (credits) to net income	(2.4)	(13.6)	(7.3)	(40.6)
Reclassification of losses (gains) to net income	3.6	1.6	10.8	4.9
Other comprehensive income (loss), before tax	(0.9)	(3.5)	(18.3)	(42.7)
Income tax benefit related to items of comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss)	(0.9)	(3.5)	(18.3)	(42.7)
Comprehensive income	84	35.9	183.7	189.7
Less: Comprehensive income attributable to noncontrolling interests	17.7	17.1	49.5	48.5
Comprehensive income attributable to AK Steel Holding Corporation	$ 66.3	$ 18.8	$ 134.2	$ 141.2

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 47.3	$ 38
Accounts receivable, net	700.7	517.8
Inventory	1,345.5	1,385
Other current assets	78.9	130.3
Total current assets	2,172.4	2,071.1
Property, plant and equipment	6,916.1	6,831.8
Accumulated depreciation	(5,007)	(4,845.6)
Property, plant and equipment, net	1,909.1	1,986.2
Other non-current assets	406.4	417.5
TOTAL ASSETS	4,487.9	4,474.8
Current liabilities:
Accounts payable	773.6	690.4
Accrued liabilities	257.3	270.5
Current portion of pension and other postretirement benefit obligations	38.8	40.1
Total current liabilities	1,069.7	1,001
Non-current liabilities:
Long-term debt	2,034.9	2,110.1
Pension and other postretirement benefit obligations	797.5	894.2
Other non-current liabilities	148	168.9
TOTAL LIABILITIES	4,050.1	4,174.2
Equity:
Common stock, authorized 450,000,000 shares of $0.01 par value each; issued 316,569,578 and 315,782,764 shares in 2018 and 2017; outstanding 315,510,490 and 314,884,569 shares in 2018 and 2017	3.2	3.2
Additional paid-in capital	2,893.3	2,884.8
Treasury stock, common shares at cost, 1,059,088 and 898,195 shares in 2018 and 2017	(6.4)	(5.4)
Accumulated deficit	(2,725.3)	(2,877)
Accumulated other comprehensive loss	(67.7)	(50.2)
Total stockholders’ equity (deficit)	97.1	(44.6)
Noncontrolling interests	340.7	345.2
TOTAL EQUITY	437.8	300.6
TOTAL LIABILITIES AND EQUITY	4,487.9	4,474.8
SunCoke Middletown [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Current assets:
Cash and cash equivalents	5.2	0.1
Inventory	22	18.4
Property, plant and equipment	426.4	425.9
Accumulated depreciation	(100)	(88.6)
Current liabilities:
Accounts payable	14.9	11.3
Other assets (liabilities), net	0.6	(1)
Equity:
Noncontrolling interests	339.3	343.5
Other Variable Interest Entities [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Current assets:
Cash and cash equivalents	0.4	0.7
Property, plant and equipment	11.7	11.7
Accumulated depreciation	(9.8)	(9.6)
Current liabilities:
Other assets (liabilities), net	0.6	0.8
Equity:
Noncontrolling interests	$ 1.4	$ 1.7

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) Parentheticals - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Common Stock, Shares Authorized	450,000,000	450,000,000
Common Stock, Par Value	$ 0.01	$ 0.01
Common Stock, Shares Issued	316,569,578	315,782,764
Common Stock, Shares Outstanding	315,510,490	314,884,569
Treasury Stock, Shares	1,059,088	898,195

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Payments to Acquire Businesses, Net of Cash Acquired	$ 0	$ 360.9
Cash flows from operating activities:
Net income	202	232.4
Depreciation	164.8	168.2
Amortization	24.5	17.9
Deferred income taxes	(6.3)	4.9
Pension and OPEB expense (income)	(24.2)	(48.6)
Contributions to pension trust	(40.7)	(38.1)
Other postretirement benefit payments	(28.5)	(30)
Changes in working capital	(11.1)	(156.2)
Other operating items, net	(30.6)	3.5
Net cash flows from operating activities	249.9	154
Cash flows from investing activities:
Capital investments	(101.1)	(88.7)
Other investing items, net	0.2	4.2
Net cash flows from investing activities	(100.9)	(445.4)
Cash flows from financing activities:
Net borrowings (payments) under credit facility	(85)	415
Proceeds from issuance of long-term debt	0	680
Redemption of long-term debt	0	(821.8)
Debt issuance costs	0	(25)
SunCoke Middletown distributions to noncontrolling interest owners	(54)	(58.2)
Other financing items, net	(0.7)	(2.5)
Net cash flows from financing activities	(139.7)	187.5
Net increase (decrease) in cash and cash equivalents	9.3	(103.9)
Cash and cash equivalents, beginning of period	38	173.2
Cash and cash equivalents, end of period	47.3	69.3
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Cash flows from operating activities:
Depreciation	153.3	155.8
Variable Interest Entity, Primary Beneficiary [Member] | SunCoke Middletown [Member]
Cash flows from operating activities:
Depreciation	11.5	12.4
Net cash flows from operating activities	$ 60.4	$ 59.2

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (DEFICIT) (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Cumulative effect of adopting new hedging standard					$ 0	$ 0
Beginning Balance at Dec. 31, 2016		$ 3.1	$ 2,855.4	$ (2.4)	(2,980.5)	(88.7)	$ 362.9
Share-based compensation		0.1	6.5
Stock options exercised			0.5
Exchangeable notes exchange feature			21.3
Purchase of treasury stock				(3)
Net income	$ 232.4				183.9		48.5
Change in accumulated other comprehensive income (loss)						(42.7)
Net distributions to noncontrolling interests							(58.2)
Ending Balance at Sep. 30, 2017	306.7	3.2	2,883.7	(5.4)	(2,796.6)	(131.4)	353.2
Cumulative effect of adopting new hedging standard					0	0
Beginning Balance at Jun. 30, 2017		3.2	2,882.6	(5.4)	(2,818.9)	(127.9)	352.4
Share-based compensation		0	1.1
Stock options exercised			0
Exchangeable notes exchange feature			0
Purchase of treasury stock				0
Net income	39.4				22.3		17.1
Change in accumulated other comprehensive income (loss)						(3.5)
Net distributions to noncontrolling interests							(16.3)
Ending Balance at Sep. 30, 2017	306.7	3.2	2,883.7	(5.4)	(2,796.6)	(131.4)	353.2
Cumulative effect of adopting new hedging standard					(0.8)	0.8
Beginning Balance at Dec. 31, 2017	300.6	3.2	2,884.8	(5.4)	(2,877)	(50.2)	345.2
Share-based compensation		0	7.8
Stock options exercised			0.7
Exchangeable notes exchange feature			0
Purchase of treasury stock				(1)
Net income	202				152.5		49.5
Change in accumulated other comprehensive income (loss)						(18.3)
Net distributions to noncontrolling interests							(54)
Ending Balance at Sep. 30, 2018	437.8	3.2	2,893.3	(6.4)	(2,725.3)	(67.7)	340.7
Cumulative effect of adopting new hedging standard					0	0
Beginning Balance at Jun. 30, 2018		3.2	2,891.1	(6.4)	(2,792.5)	(66.8)	342.2
Share-based compensation		0	1.5
Stock options exercised			0.7
Exchangeable notes exchange feature			0
Purchase of treasury stock				0
Net income	84.9				67.2		17.7
Change in accumulated other comprehensive income (loss)						(0.9)
Net distributions to noncontrolling interests							(19.2)
Ending Balance at Sep. 30, 2018	$ 437.8	$ 3.2	$ 2,893.3	$ (6.4)	$ (2,725.3)	$ (67.7)	$ 340.7

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation— These financial statements consolidate the operations and accounts of AK Steel Holding Corporation (“AK Holding”), its wholly-owned subsidiary AK Steel Corporation (“AK Steel”), all subsidiaries in which AK Holding has a controlling interest, and two variable interest entities for which AK Steel is the primary beneficiary. Unless the context provides otherwise, references to “we,” “us” and “our” refer to AK Holding and its subsidiaries. In our opinion, the accompanying condensed consolidated financial statements contain all adjustments, consisting of normal recurring adjustments, necessary to present fairly our financial position as of September 30, 2018 and December 31, 2017 , our results of operations for the three and nine months ended September 30, 2018 and 2017 , and our cash flows for the nine months ended September 30, 2018 and 2017 . Our results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results we expect for the full year ending December 31, 2018 . These condensed consolidated financial statements should be read along with our audited consolidated financial statements for the year ended December 31, 2017 , included in our Annual Report on Form 10-K for the year ended December 31, 2017 . Revenue Recognition— We generate our revenue through product sales, and shipping terms generally indicate when we have fulfilled our performance obligations and passed control of products to our customer. Our revenue transactions consist of a single performance obligation to transfer promised goods. We have contracts with a substantial portion of our customers. These contracts usually define the mechanism for determining the sales price, but the contacts do not impose a specific quantity on either party. Quantities to be delivered to the customer are determined at a point near the date of delivery through purchase orders or other written instructions we receive from the customer. Spot market sales are made through purchase orders or other written instructions. We recognize revenue when we have fulfilled a performance obligation, which is typically when we have shipped products at the customer’s instructions. For sales with shipping terms that transfer title and risk of loss at the destination point, we recognize revenue when the customer receives the goods and our performance obligation is complete. For sales with shipping terms that transfer title and risk of loss at the shipping point with us bearing responsibility for freight costs to the destination, we determine that we have fulfilled a single performance obligation and recognize revenue when we ship the goods. For our tooling solutions, we record progress payments that we receive from a customer as accrued liabilities until we recognize the revenue when the customer provides written acceptance that our performance obligation has been fulfilled. Revenue is measured as the consideration we expect to receive in exchange for transferring product. We reduce the revenue recognized for estimated returns and other customer credits, such as discounts and volume rebates, based on the expected value to be realized. Payment terms are consistent with terms standard to the markets we serve. We maintain an allowance for doubtful accounts for the loss that would be incurred if a customer is unable to pay amounts due. We initially estimate the allowance required at the time of revenue recognition based on historical experience and make changes to the allowance based on various factors, including changes in the customer’s financial condition or payment patterns. Sales taxes collected from customers are excluded from revenues. Inventory— Inventories are valued at the lower of cost or net realizable value. We measure the cost of inventories using the average cost method. See Note 3 for information on the change to the average cost method effective January 1, 2018. Pension and Other Postretirement Benefits— On January 1, 2018, we adopted Accounting Standards Update No. 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . Under this standard, the service cost component of periodic pension and other postretirement benefit expense is included in cost of products sold and selling and administrative expenses, consistent with our treatment of other employee compensation costs. The remainder of periodic pension and other postretirement benefit income of $10.0 and $18.1 for the three months ended September 30, 2018 and 2017 and $30.0 and $54.3 for the nine months ended September 30, 2018 and 2017

Acquisition of Precision Partne

Acquisition of Precision Partners (Notes)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	Acquisition of Precision Partners On August 4, 2017 , we acquired 100% of the equity of PPHC Holdings, LLC (“Precision Partners”), which provides advanced-engineered solutions, tool design and build, hot- and cold-stamped steel components and complex assemblies for the automotive market. Precision Partners is headquartered in Ontario, Canada and operates eight plants in Ontario, Alabama and Kentucky. We acquired Precision Partners to complement and bolster our core focus on the high-growth automotive lightweighting market, enhance our prominent position in advanced high strength steels, further strengthen close collaboration with automotive market customers, and leverage both companies’ research and innovation in materials and metals-forming. We finalized the purchase price allocation as of March 31, 2018. For the three and nine months ended September 30, 2017, we incurred acquisition costs of $4.7 and $6.2

Supplementary Financial Stateme

Supplementary Financial Statement Information (Notes)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Supplementary Financial Statement Information	Supplementary Financial Statement Information Revenue Net sales by market are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Automotive $ 1,036.7 $ 948.8 $ 3,264.5 $ 2,986.0 Infrastructure and Manufacturing 277.1 239.3 782.2 717.9 Distributors and Converters 421.8 306.2 1,094.4 881.0 Total $ 1,735.6 $ 1,494.3 $ 5,141.1 $ 4,584.9 Net sales by product line are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Carbon steel $ 1,132.6 $ 995.7 $ 3,303.6 $ 3,073.0 Stainless and electrical steel 454.3 401.2 1,363.5 1,279.2 Tubular products, components and other 148.7 97.4 474.0 232.7 Total $ 1,735.6 $ 1,494.3 $ 5,141.1 $ 4,584.9 We sell domestically to customers located primarily in the Midwestern and Eastern United States and to foreign customers, primarily in Canada, Mexico and Western Europe. Net sales to customers located outside the United States were $149.6 and $490.3 for the three and nine months ended September 30, 2018 , compared to $159.4 and $472.2 for the corresponding periods in 2017 . Inventory Inventories as of September 30, 2018 and December 31, 2017 , are presented below: September 30, December 31, Finished and semi-finished $ 1,014.4 $ 996.8 Raw materials 331.1 388.2 Inventory $ 1,345.5 $ 1,385.0 In the first quarter of 2018, we changed our accounting method for valuing certain inventories from the last-in, first-out (LIFO) method to the average cost method. This method values inventory using average costs for materials and most recent production costs for labor and overhead. We believe that using the average cost method is preferable since it improves comparability with our peers, more closely tracks the physical flow of our inventory, better matches revenue with expenses and aligns with how we internally manage our business. The effects of the change in accounting principle from LIFO to average cost have been retrospectively applied to all periods presented. As a result of the retrospective application of the change in accounting principle, certain financial statement line items in our condensed consolidated balance sheet as of December 31, 2017 and our condensed consolidated statements of operations and comprehensive income and cash flows for the three and nine months ended September 30, 2017 were adjusted as follows: As Originally Reported Effect of Change As Adjusted Condensed consolidated statement of operations for the three months ended September 30, 2017: Cost of products sold (a) $ 1,348.4 $ (46.6 ) $ 1,301.8 Income tax expense (benefit) (18.8 ) 18.5 (0.3 ) Net income 11.3 28.1 39.4 Net income attributable to AK Steel Holding Corporation (5.8 ) 28.1 22.3 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ (0.02 ) $ 0.09 $ 0.07 Diluted (0.02 ) 0.09 0.07 Condensed consolidated statement of operations for the nine months ended September 30, 2017: Cost of products sold (a) $ 4,005.7 $ (107.0 ) $ 3,898.7 Income tax expense (benefit) (40.9 ) 41.0 0.1 Net income 166.4 66.0 232.4 Net income attributable to AK Steel Holding Corporation 117.9 66.0 183.9 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.37 $ 0.21 $ 0.58 Diluted 0.37 0.20 0.57 Condensed consolidated statement of comprehensive income for the three months ended September 30, 2017: Cash flow hedges—Reclassification of losses (gains) to net income $ (1.9 ) $ 1.7 $ (0.2 ) Comprehensive income 6.1 29.8 35.9 Comprehensive income attributable to AK Steel Holding Corporation (11.0 ) 29.8 18.8 Condensed consolidated statement of comprehensive income for the nine months ended September 30, 2017: Cash flow hedges—Reclassification of losses (gains) to net income $ (7.2 ) $ 5.1 $ (2.1 ) Comprehensive income 118.6 71.1 189.7 Comprehensive income attributable to AK Steel Holding Corporation 70.1 71.1 141.2 Condensed consolidated balance sheet as of December 31, 2017: Inventory $ 1,147.8 $ 237.2 $ 1,385.0 Other non-current assets 476.0 (58.5 ) 417.5 Other non-current liabilities 161.6 7.3 168.9 Accumulated deficit (3,058.6 ) 181.6 (2,877.0 ) Accumulated other comprehensive loss (40.0 ) (10.2 ) (50.2 ) As Originally Reported Effect of Change As Adjusted Condensed consolidated statement of cash flows for the nine months ended September 30, 2017: Net income $ 166.4 $ 66.0 $ 232.4 Deferred income taxes (36.1 ) 41.0 4.9 Changes in working capital (44.1 ) (112.1 ) (156.2 ) Other operating items, net (1.6 ) 5.1 3.5 (a) Cost of products sold as originally reported reflects the change in presentation of pension and OPEB (income) expense further described in Note 1 . The following table shows the effects of the change in accounting principle from LIFO to average cost as of September 30, 2018 and for the three and nine months ended September 30, 2018 : As Computed under LIFO As Reported under Average Cost Effect of Change Condensed consolidated statement of operations for the three months ended September 30, 2018: Cost of products sold $ 1,499.7 $ 1,486.2 $ (13.5 ) Income tax expense (benefit) (1.9 ) 1.4 3.3 Net income 74.7 84.9 10.2 Net income attributable to AK Steel Holding Corporation 57.0 67.2 10.2 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.18 $ 0.21 $ 0.03 Diluted 0.18 0.21 0.03 Condensed consolidated statement of operations for the nine months ended September 30, 2018: Cost of products sold $ 4,504.8 $ 4,462.6 $ (42.2 ) Income tax expense (benefit) (13.9 ) (4.0 ) 9.9 Net income 169.7 202.0 32.3 Net income attributable to AK Steel Holding Corporation 120.2 152.5 32.3 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.38 $ 0.48 $ 0.10 Diluted 0.38 0.48 0.10 Condensed consolidated statement of comprehensive income for the three months ended September 30, 2018: Comprehensive income $ 73.8 $ 84.0 $ 10.2 Comprehensive income attributable to AK Steel Holding Corporation 56.1 66.3 10.2 Condensed consolidated statement of comprehensive income for the nine months ended September 30, 2018: Comprehensive income $ 151.4 $ 183.7 $ 32.3 Comprehensive income attributable to AK Steel Holding Corporation 101.9 134.2 32.3 Condensed consolidated balance sheet as of September 30, 2018: Inventory $ 1,067.8 $ 1,345.5 $ 277.7 Other non-current assets 480.1 406.4 (73.7 ) Other non-current liabilities 146.0 148.0 2.0 Accumulated deficit (2,939.2 ) (2,725.3 ) 213.9 Condensed consolidated statement of cash flows for the nine months ended September 30, 2018: Net income $ 169.7 $ 202.0 $ 32.3 Deferred income taxes (16.2 ) (6.3 ) 9.9 Changes in working capital 29.4 (11.1 ) (40.5 ) Other operating items, net (28.9 ) (30.6 ) (1.7 ) Other Non-Current Assets The change in goodwill for the nine months ended September 30, 2018 , was as follows. 2018 Balance at beginning of period $ 253.8 Adjustment to acquisition purchase price 1.2 Balance at end of period $ 255.0 Intangible assets at September 30, 2018 and December 31, 2017 , consist of: Gross Amount Accumulated Amortization Net Amount As of September 30, 2018 Customer relationships $ 36.6 $ (6.1 ) $ 30.5 Technology 19.3 (3.8 ) 15.5 Other 1.0 (1.0 ) — Intangible assets $ 56.9 $ (10.9 ) $ 46.0 As of December 31, 2017 Customer relationships $ 36.6 $ (2.2 ) $ 34.4 Technology 19.3 (1.4 ) 17.9 Other 1.0 (0.4 ) 0.6 Intangible assets $ 56.9 $ (4.0 ) $ 52.9 Amortization expense related to intangible assets was $2.2 and $6.9 for the three and nine months ended September 30, 2018 and $1.8 and $1.8 for the three and nine months ended September 30, 2017 . Investments in Affiliates We have investments in several businesses accounted for using the equity method of accounting. Summarized financial statement data for all investees is presented below. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue $ 88.9 $ 73.2 $ 247.2 $ 222.5 Gross profit 24.5 20.5 69.2 69.6 Net income 6.4 3.4 15.7 18.8 Our share of income of equity investees (included in cost of products sold) 2.5 1.0 5.5 6.6 Facility Idling In the fourth quarter of 2015, we temporarily idled the Ashland Works blast furnace and steelmaking operations (“Ashland Works Hot End”). We incurred on-going costs of $4.7 and $5.1 for the three months ended September 30, 2018 and 2017 and $15.1 and $15.9 for the nine months ended September 30, 2018 and 2017 , for maintenance of the equipment, utilities and supplier obligations related to the Ashland Works Hot End. We continue to engage in regular reviews of the potential viability of the Ashland Works Hot End, including an assessment of the most significant risks and benefits of a permanent idling of those idled operations. As part of these reviews, we take into consideration, among other items, our strategic focus on reducing participation in commodity markets to position the company for sustainable profitability and whether we anticipate that future market conditions will enable production from the

Income Taxes (Notes)

Income Taxes (Notes)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income taxes recorded for the periods ended September 30, 2018 and 2017 , were estimated using the discrete method. Income taxes are based on our financial results through the end of the period, as well as the related change in the valuation allowance on deferred tax assets. We are unable to estimate the annual effective tax rate with sufficient precision for purposes of the effective tax rate method, which requires us to consider a projection of full-year income and the expected change in the valuation allowance. The estimated annual effective tax rate method was not reliable due to its sensitivity to small changes to forecasted annual pre-tax earnings and the effect of our valuation allowance, which create results with significant variations in the customary relationship between income tax expense and pre-tax income for the interim periods. As a result, we determined that using the discrete method is more appropriate than using the annual effective tax rate method. During the first nine months of 2018, we reduced our valuation allowance and recorded an income tax benefit of $5.3 as a result of changes to the tax net operating carryover rules included in the Tax Cuts and Jobs Act of 2017 that allow us to use certain indefinite-lived deferred tax liabilities as a source of future income to realize deferred tax assets. We have not completed our determination of the accounting implications of the Tax Cuts and Jobs Act of 2017 on our tax balances. However, we have reasonably estimated the provisional effects of the act in these condensed consolidated financial statements.

Long-term Debt and Other Financ

Long-term Debt and Other Financing Long-term Debt and Other Financing (Notes)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-term Debt and Other Financing	Long-term Debt and Other Financing Debt balances at September 30, 2018 and December 31, 2017 , are presented below: September 30, December 31, Credit Facility $ 365.0 $ 450.0 7.50% Senior Secured Notes due July 2023 (effective rate of 8.3%) 380.0 380.0 5.00% Exchangeable Senior Notes due November 2019 (effective rate of 10.8%) 150.0 150.0 7.625% Senior Notes due October 2021 406.2 406.2 6.375% Senior Notes due October 2025 (effective rate of 7.1%) 280.0 280.0 7.00% Senior Notes due March 2027 400.0 400.0 Industrial Revenue Bonds due 2020 through 2028 99.3 99.3 Unamortized debt discount and issuance costs (45.6 ) (55.4 ) Total long-term debt $ 2,034.9 $ 2,110.1 During the nine months ended September 30, 2018 , we were in compliance with all the terms and conditions of our debt agreements. In the three and nine months ended September 30, 2017 , we recognized other expense of $8.4 and $21.5 for expenses related to the repurchase of senior unsecured notes. Credit Facility We have a $1,350.0 revolving credit facility (the “Credit Facility”), which expires in September 2022 . As of September 30, 2018 , we had outstanding borrowings of $365.0 under the Credit Facility, a decrease of $85.0 from $450.0 at December 31, 2017 . At September 30, 2018 , our eligible collateral, after application of applicable advance rates, was in excess of $1,350.0 . Availability as of September 30, 2018 , was $911.8 after reductions of $73.2

Pension and Other Postretiremen

Pension and Other Postretirement Benefits (Notes)	9 Months Ended
	Sep. 30, 2018
Retirement Benefits, Description [Abstract]
Pension and Other Postretirement Benefits	Pension and Other Postretirement Benefits Net periodic benefit (income) expense for pension and other postretirement benefits was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Pension Benefits Service cost $ 0.9 $ 0.7 $ 2.4 $ 2.1 Interest cost 23.7 27.0 71.2 81.0 Expected return on assets (38.8 ) (37.5 ) (116.4 ) (112.6 ) Amortization of prior service cost 1.0 1.1 2.9 3.4 Amortization of loss 3.9 2.7 11.8 8.1 Net periodic benefit (income) expense $ (9.3 ) $ (6.0 ) $ (28.1 ) $ (18.0 ) Other Postretirement Benefits Service cost $ 1.1 $ 1.2 $ 3.4 $ 3.5 Interest cost 3.9 4.4 11.7 13.1 Amortization of prior service cost (credit) (3.4 ) (14.7 ) (10.2 ) (44.0 ) Amortization of (gain) loss (0.3 ) (1.1 ) (1.0 ) (3.2 ) Net periodic benefit (income) expense $ 1.3 $ (10.2 ) $ 3.9 $ (30.6 ) We have funded our $49.9 of required contributions to the master pension trust for 2018 , which included contributions of $40.7 through September 30, 2018 and the remaining $9.2 contribution in October 2018. Based on current actuarial assumptions, we estimate that our required pension contributions will be approximately $40.0 in 2019 and $80.0 in 2020. Factors that affect our estimates of future funding projections include return on plan assets, actuarial data and assumptions relating to plan participants, the discount rate used to measure the pension obligations and changes to regulatory funding requirements. In October 2018, we purchased a non-participating annuity contract with an insurance company using pension trust assets and transferred to the insurance company certain pension obligations of approximately $280.0 for approximately 5,400 retirees or their beneficiaries receiving pension payments for amounts at similar levels to their associated obligations. As a result of this transfer, we expect to record a settlement loss of approximately $3.0

Environmental and Legal Conting

Environmental and Legal Contingencies (Notes)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Environmental and Legal Contingencies	Environmental and Legal Contingencies Environmental Contingencies We and our predecessors have been involved in steel manufacturing and related operations since 1900. Although we believe our operating practices have been consistent with prevailing industry standards, hazardous materials may have been released at operating sites or third-party sites in the past, including operating sites that we no longer own. If we reasonably can, we have estimated potential remediation expenditures for those sites where future remediation efforts are probable based on identified conditions, regulatory requirements or contractual obligations arising from the sale of a business or facility. For sites involving government-required investigations, we typically make an estimate of potential remediation expenditures only after the investigation is complete and when we better understand the nature and scope of the remediation. In general, the material factors in these estimates include the costs associated with investigations, delineations, risk assessments, remedial work, governmental response and oversight, site monitoring, and preparation of reports to the appropriate environmental agencies. We have recorded the following liabilities for environmental matters on our condensed consolidated balance sheets: September 30, December 31, Accrued liabilities $ 8.0 $ 8.5 Other non-current liabilities 30.2 35.4 We cannot predict the ultimate costs for each site with certainty because of the evolving nature of the investigation and remediation process. Rather, to estimate the probable costs, we must make certain assumptions. The most significant of these assumptions is for the nature and scope of the work that will be necessary to investigate and remediate a particular site and the cost of that work. Other significant assumptions include the cleanup technology that will be used, whether and to what extent any other parties will participate in paying the investigation and remediation costs, reimbursement of past response and future oversight costs by governmental agencies, and the reaction of the governing environmental agencies to the proposed work plans. Costs for future investigation and remediation are not discounted to their present value. To the extent that we have been able to reasonably estimate future liabilities, we do not believe that there is a reasonable possibility that we will incur a loss or losses that exceed the amounts we accrued for the environmental matters discussed below that would, either individually or in the aggregate, have a material adverse effect on our consolidated financial condition, results of operations or cash flows. However, since we recognize amounts in the consolidated financial statements in accordance with accounting principles generally accepted in the United States that exclude potential losses that are not probable or that may not be currently estimable, the ultimate costs of these environmental proceedings may be higher than the liabilities we currently have recorded in our consolidated financial statements. Except as we expressly note below, we do not currently anticipate any material effect on our consolidated financial position, results of operations or cash flows as a result of compliance with current environmental regulations. Moreover, because all domestic steel producers operate under the same federal environmental regulations, we do not believe that we are more disadvantaged than our domestic competitors by our need to comply with these regulations. Some foreign competitors may benefit from less stringent environmental requirements in the countries where they produce, resulting in lower compliance costs for them and providing those foreign competitors with a cost advantage on their products. According to the Resource Conservation and Recovery Act (“RCRA”), which governs the treatment, handling and disposal of hazardous waste, the United States Environmental Protection Agency (“EPA”) and authorized state environmental agencies may conduct inspections of RCRA-regulated facilities to identify areas where there have been releases of hazardous waste or hazardous constituents into the environment and may order the facilities to take corrective action to remediate such releases. Environmental regulators may inspect our major steelmaking facilities. While we cannot predict the future actions of these regulators, it is possible that they may identify conditions in future inspections of these facilities which they believe require corrective action. Under authority from the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”), the EPA and state environmental authorities have conducted site investigations at certain of our facilities and other third-party facilities, portions of which previously may have been used for disposal of materials that are currently regulated. The results of these investigations are still pending, and we could be directed to spend funds for remedial activities at the former disposal areas. Because of the uncertain status of these investigations, however, we cannot reliably predict whether or when such spending might be required or its magnitude. As previously noted, on April 29, 2002, we entered a mutually agreed-upon administrative order on consent with the EPA pursuant to Section 122 of CERCLA to perform a Remedial Investigation/Feasibility Study (“RI/FS”) of the Hamilton Plant site located in New Miami, Ohio. The plant ceased operations in 1990 and all of its former structures have been demolished. We submitted the investigation portion of the RI/FS, and we completed a supplemental study in 2014. We currently have accrued $0.7 for the remaining cost of the RI/FS. Until the RI/FS is complete, we cannot reliably estimate the additional costs, if any, we may incur for potentially required remediation of the site or when we may incur them. As previously reported, on September 30, 1998, our predecessor, Armco Inc., received an order from the EPA under Section 3013 of RCRA requiring it to develop a plan for investigation of eight areas of our Mansfield Works that allegedly could be sources of contamination. A site investigation began in November 2000 and is continuing. We cannot reliably estimate how long it will take to complete this site investigation. We currently have accrued $1.1 for the projected cost of the study. Until the site investigation is complete, we cannot reliably estimate the additional costs, if any, we may incur for potentially required remediation of the site or when we may incur them. As previously noted, on September 26, 2012, the EPA issued an order under Section 3013 of RCRA requiring us to develop a plan for investigation of four areas at our Ashland Works coke plant. The Ashland Works coke plant ceased operations in 2011 and all of its former structures have been demolished and removed. In 1981, we acquired the plant from Honeywell International Corporation (as successor to Allied Corporation), who had managed the coking operations there for approximately 60 years. In connection with the sale of the coke plant, Honeywell agreed to indemnify us from certain claims and obligations that could arise from the site investigation and we intend to pursue such indemnification from Honeywell, if necessary. We cannot reliably estimate how long it will take to complete the site investigation. On March 10, 2016, the EPA invited us to participate in settlement discussions regarding an enforcement action. Settlement discussions between the parties are ongoing, though whether the parties will reach agreement and any such agreement’s terms are uncertain. We currently have accrued $1.4 for the projected cost of the investigation and known remediation. Until the site investigation is complete, we cannot reliably estimate the costs, if any, we may incur for potential additional required remediation of the site or when we may incur them. As previously reported, on July 15, 2009, we and the Pennsylvania Department of Environmental Protection (“PADEP”) entered a Consent Order and Agreement (the “Consent Order”) to resolve an alleged unpermitted discharge of wastewater from the closed Hillside Landfill at our former Ambridge Works. Under the terms of the Consent Order, we paid a penalty and also agreed to implement various corrective actions, including an investigation of the area where landfill activities occurred, submission of a plan to collect and treat surface waters and seep discharges, and upon approval from PADEP, implementation of that plan. We have accrued $5.6 for the remedial work required under the approved plan and Consent Order. We submitted a National Pollution Discharge Elimination System (“NPDES”) permit application to move to the next work phase. We currently estimate that the remaining work will be completed in 2019, though it may be delayed. As previously reported, on June 29, 2000, the United States filed a complaint on behalf of the EPA against us in the U.S. District Court for the Southern District of Ohio, Case No. C-1-00530, alleging violations of the Clean Air Act, the Clean Water Act and RCRA at our Middletown Works. Subsequently, the State of Ohio, the Sierra Club and the National Resources Defense Council intervened. On May 15, 2006, the court entered a Consent Decree in Partial Resolution of Pending Claims (the “Consent Decree”). Under the Consent Decree, we agreed to undertake a comprehensive RCRA facility investigation at Middletown Works and, as appropriate, complete a corrective measures study. The Consent Decree required us to implement certain RCRA corrective action interim measures to address polychlorinated biphenyls (“PCBs”) in sediments and soils at Dicks Creek and certain other specified surface waters, adjacent floodplain areas and other previously identified geographic areas. We have completed the remedial activity at Dicks Creek, but continue to work on the RCRA facility investigation and certain interim measures. We have accrued $12.8 for the cost of known work required under the Consent Decree. As previously reported, on May 12, 2014, the Michigan Department of Environmental Quality (“MDEQ”) issued to our Dearborn Works an Air Permit to Install No. 182-05C (the “PTI”) to increase the emission limits for the blast furnace and other emission sources. The PTI was issued as a correction to a prior permit to install that did not include certain information during the prior permitting process. On July 10, 2014, the South Dearborn Environmental Improvement Association (“SDEIA”), Detroiters Working for Environmental Justice, Original United Citizens of Southwest Detroit and the Sierra Club filed a Claim of Appeal of the PTI in the State of Michigan, Wayne County Circuit, Case No. 14-008887-AA. Appellants and the MDEQ required the intervention of Severstal Dearborn, LLC (“Dearborn”) (now owned by us) in this action as an additional appellee. The appellants allege multiple deficiencies with the PTI and the permitting process. Until the appeal is resolved, we cannot determine what the ultimate permit limits will be. Until the permit limits are determined and final, we cannot reliably estimate the costs we may incur, if any, or when we may incur them. As previously reported, on August 21, 2014, the SDEIA filed a Complaint under the Michigan Environmental Protection Act (“MEPA”) in the State of Michigan, Wayne County Circuit Case No. 14-010875-CE. The plaintiffs allege that the air emissions from our Dearborn Works are impacting the air, water and other natural resources, as well as the public trust in such resources. The plaintiffs are requesting, among other requested relief, that the court assess and determine the sufficiency of the PTI’s limitations. On October 15, 2014, the court ordered a stay of the proceedings until a final order is issued in Wayne County Circuit Court Case No. 14-008887-AA (discussed above). When the proceedings resume, we will vigorously contest these claims. Until the claims in this Complaint are resolved, we cannot reliably estimate the costs we may incur, if any, or when we may incur them. As previously reported, on April 27, 2000, MDEQ issued a RCRA Corrective Action Order No. 111-04-00-07E to Rouge Steel Company and Ford Motor Company for the property that includes our Dearborn Works. We are a party to the Corrective Action Order as the successor-in-interest to Dearborn, which was the successor-in-interest to Rouge Steel Company. The Corrective Action Order requires the site-wide investigation, and where appropriate, remediation of the facility. The site investigation and remediation are ongoing. We cannot reliably estimate how long it will take to complete this site investigation and remediation. To date, Ford Motor Company has incurred most of investigation and remediation costs due to its prior ownership of the steelmaking operations at Dearborn Works. Until the site investigation is complete, we cannot reliably estimate the additional costs we may incur, if any, for any potentially required remediation of the site or when we may incur them. As previously reported, AK Steel received an order in October 2002 from the EPA under Section 3013 of RCRA requiring it to investigate several areas of Zanesville Works that allegedly could be sources of contamination. A site investigation began in 2003 and was approved by EPA in November 2012. On October 28, 2016, the EPA requested that we conduct a corrective measures study and implement these measures as necessary. We subsequently agreed to proceed with a voluntary corrective measures study and have accrued $0.1 for the study. Until it is complete, we cannot reliably estimate the costs, if any, we may incur for potential required remediation of the site or when we may incur them. In addition to the foregoing matters, we are or may be involved in proceedings with various regulatory authorities that may require us to pay fines, comply with more rigorous standards or other requirements or incur capital and operating expenses for environmental compliance. We believe that the ultimate disposition of the proceedings will not have, individually or in the aggregate, a material adverse effect on our consolidated financial condition, results of operations or cash flows. Legal Contingencies As previously reported, since 1990 we have been named as a defendant in numerous lawsuits alleging personal injury as a result of exposure to asbestos. The great majority of these lawsuits have been filed on behalf of people who claim to have been exposed to asbestos while visiting the premises of one of our current or former facilities. The majority of asbestos cases pending in which we are a defendant do not include a specific dollar claim for damages. In the cases that do include specific dollar claims for damages, the complaint typically includes a monetary claim for compensatory damages and a separate monetary claim in an equal amount for punitive damages and does not attempt to allocate the total monetary claim among the various defendants. The number of asbestos cases pending at September 30, 2018 , is presented below: Asbestos Cases Pending at September 30, 2018 Cases with specific dollar claims for damages: Claims up to $0.2 151 Claims above $0.2 to $5.0 4 Claims above $5.0 to $20.0 3 Total claims with specific dollar claims for damages (a) 158 Cases without a specific dollar claim for damages 172 Total asbestos cases pending 330 (a) Involve a total of 2,223 plaintiffs and 18,453 defendants In each case, the amount described is per plaintiff against all of the defendants, collectively. Thus, it usually is not possible at the outset of a case to determine the specific dollar amount of a claim against us. In fact, it usually is not even possible at the outset to determine which of the plaintiffs actually will pursue a claim against us. Typically, that can only be determined through written interrogatories or other discovery after a case has been filed. Therefore, in a case involving multiple plaintiffs and multiple defendants, we initially only account for the lawsuit as one claim. After we have determined through discovery whether a particular plaintiff will pursue a claim, we make an appropriate adjustment to statistically account for that specific claim. It has been our experience that only a small percentage of asbestos plaintiffs ultimately identify us as a target defendant from whom they actually seek damages and most of these claims ultimately are either dismissed or settled for a small fraction of the damages initially claimed. Asbestos-related claims information for the three and nine months ended September 30, 2018 and 2017 is presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 New Claims Filed 13 18 46 46 Pending Claims Disposed Of 10 27 52 51 Total Amount Paid in Settlements $ 0.2 $ 0.3 $ 0.9 $ 0.9 Since the onset of asbestos claims against us in 1990, five asbestos claims against us have proceeded to trial in four separate cases. All five concluded with a verdict in our favor. We continue to vigorously defend the asbestos claims. Based upon present knowledge, and the factors above, we believe it is unlikely that the resolution in the aggregate of the asbestos claims against us will have a materially adverse effect on our consolidated results of operations, cash flows or financial condition. However, predictions about the outcome of pending litigation, particularly claims alleging asbestos exposure, are subject to substantial uncertainties. These uncertainties include (1) the significantly variable rate at which new claims may be filed, (2) the effect of bankruptcies of other companies currently or historically defending asbestos claims, (3) the litigation process from jurisdiction to jurisdiction and from case to case, (4) the type and severity of the disease each claimant alleged to suffer, and (5) the potential for enactment of legislation affecting asbestos litigation. As previously reported, in September and October 2008 and again in July 2010, several companies filed purported class actions in the United States District Court for the Northern District of Illinois against nine steel manufacturers, including us. The case numbers for these actions are 08CV5214, 08CV5371, 08CV5468, 08CV5633, 08CV5700, 08CV5942, 08CV6197 and 10CV04236. On December 28, 2010, another action, case number 32,321, was filed in state court in the Circuit Court for Cocke County, Tennessee. The defendants removed the Tennessee case to federal court and in March 2012 it was transferred to the Northern District of Illinois. The plaintiffs in the various pending actions are companies that purport to have purchased steel products, directly or indirectly, from one or more of the defendants and they claim to file the actions on behalf of all persons and entities who purchased steel products for delivery or pickup in the United States from any of the named defendants at any time from at least as early as January 2005. The complaints allege that the defendant steel producers have conspired in violation of antitrust laws to restrict output and to fix, raise, stabilize and maintain artificially high prices for steel products in the United States. In March 2014, we reached an agreement with the direct purchaser plaintiffs to settle the claims asserted against us. According to that settlement, we agreed to pay $5.8 to the plaintiff class of direct purchasers in exchange for the members of that class to completely release all claims. We continue to believe that the claims made against us lack any merit, but we elected to enter the settlement to avoid the ongoing expense of defending ourselves in this protracted and expensive antitrust litigation. We provided notice of the proposed settlement to members of the settlement class. After several class members received the notice, they elected to opt out of the class settlement. Following a fairness hearing, on October 21, 2014 the Court entered an order and judgment approving the settlement and dismissing all of the direct plaintiffs’ claims against us with prejudice as to the settlement class. On March 3, 2017, the Court granted the defendants’ motion to dismiss the indirect plaintiffs’ amended complaint on the grounds that the plaintiffs lacked antitrust standing. On April 4, 2017, the indirect plaintiffs filed a motion for reconsideration and the defendants filed an opposition to that motion. On July 13, 2017, the Court denied the indirect plaintiffs’ motion for reconsideration. On September 15, 2017 the indirect plaintiffs filed a notice of appeal with the Seventh Circuit Court of Appeals. On September 6, 2018, the Seventh Circuit affirmed the judgment of the District Court. At this point, it is uncertain whether the indirect plaintiffs will file a petition for a writ of certiorari with the United States Supreme Court. Because we have been unable to determine that a potential loss in this case for the indirect plaintiffs is probable or estimable, we have not recorded an accrual for this matter. If our assumptions used to evaluate a probable or estimable loss for the indirect plaintiffs prove to be incorrect or change, we may be required to record a charge for their claims. As previously reported, on January 20, 2010, ArcelorMittal France and ArcelorMittal Atlantique et Lorraine (collectively “ArcelorMittal”) filed an action in the United States District Court for the District of Delaware, Case No. 10-050-SLR against us, Dearborn, and Wheeling-Nisshin Inc., whom Dearborn indemnified in this action. By virtue of our responsibility as a successor-in-interest to Dearborn and an indemnitor of Wheeling-Nisshin Inc., we now have complete responsibility for the defense of this action. The three named defendants are collectively referred to hereafter as “we” or “us”, though the precise claims against each separate defendant may vary. The complaint alleges that we are infringing the claims of U.S. Patent No. 6,296,805 (the “Patent”) in making pre-coated cold-rolled boron steel sheet and seeks injunctive relief and unspecified compensatory damages. We filed an answer denying ArcelorMittal’s claims and raised various affirmative defenses. We also filed counterclaims against ArcelorMittal for a declaratory judgment that we are not infringing the Patent and that the Patent is invalid. Subsequently, the trial court separated the issues of liability and damages. The case proceeded with a trial to a jury on the issue of liability during the week of January 15, 2011. The jury returned a verdict that we did not infringe the Patent and that the Patent was invalid. Judgment then was entered in our favor. ArcelorMittal filed an appeal with the United States Court of Appeals for the Federal Circuit. On November 30, 2012, the court of appeals issued a decision reversing certain findings related to claim construction and the validity of the Patent and remanded the case to the trial court for further proceedings. On January 30, 2013, ArcelorMittal filed a motion for rehearing with the court of appeals. On March 20, 2013, the court of appeals denied ArcelorMittal’s motion for rehearing. The case then was remanded to the trial court for further proceedings. On April 16, 2013, according to a petition previously filed by ArcelorMittal and ArcelorMittal USA LLC, the U.S. Patent and Trademark Office (“PTO”) reissued the Patent as U.S. Reissue Patent RE44,153 (the “Reissued Patent”). Also on April 16, 2013, ArcelorMittal filed a second action against us in the United States District Court for the District of Delaware, Case Nos. 1:13-cv-00685 and 1:13-cv-00686 (collectively the “Second Action”). The complaint filed in the Second Action alleges that we are infringing the claims of the Reissued Patent and seeks injunctive relief and unspecified compensatory damages. On April 23, 2013, we filed a motion to dismiss key elements of the complaint filed in the Second Action. In addition, the parties briefed related non-infringement and claims construction issues in the original action. On October 25, 2013, the district court granted summary judgment in our favor, confirming that our product does not infringe the original Patent or the Reissued Patent. The court further ruled that ArcelorMittal’s Reissued Patent was invalid due to ArcelorMittal’s deliberate violation of a statutory prohibition on broadening a patent through reissue more than two years after the original Patent was granted and that the original Patent had been surrendered when the Reissued Patent was issued and thus is no longer in effect. Final Judgment was entered on October 31, 2013. On November 6, 2013, ArcelorMittal filed a motion to clarify or, in the alternative, to alter or amend the October 31, 2013 judgment. We opposed the motion. On December 5, 2013, the court issued a memorandum and order denying the motion and entered final judgment in our favor, and against ArcelorMittal, specifically ruling that all claims of ArcelorMittal’s Reissued Patent are invalid as violative of 35 U.S.C. §251(d). On December 30, 2013, ArcelorMittal filed notices of appeal to the Federal Circuit Court of Appeals. On May 12, 2015, the Federal Circuit issued its decision affirming in part and reversing in part the trial court’s decision and remanding the case for further proceedings. The Federal Circuit ruled that 23 of the 25 claims of the Reissued Patent were improperly broadened and therefore invalid. However, the Federal Court found that the district court erred in invalidating the remaining two claims and remanded the case for further proceedings before the district court. Following the remand, ArcelorMittal filed a motion in the trial court for leave to amend the Second Action to assert additional patent infringement claims based on another, related patent that the PTO issued on June 10, 2014, No. RE044940 (Second Reissue Patent). It also filed a motion to dismiss the original action on the grounds that it is now moot in light of the Court of Appeals’ last ruling. We opposed both of those motions. In addition, we filed separate motions for summary judgment in the original action on the grounds of non-infringement and invalidity. A hearing on all motions was held on October 27, 2015. On December 4, 2015, the district court issued an order granting our motion for summary judgment that neither of the remaining claims of the Reissued Patent are infringed and both are invalid as obvious. The court therefore entered final judgment in favor of the defendants in the original case. In the court’s order, the judge also granted ArcelorMittal’s motion to file a first amended complaint and ArcelorMittal did file an amended complaint in Case No. 1:13-cv-00685 (“685 Action”) alleging we are infringing the claims of the Second Reissue Patent, which we deny. On December 21, 2015, ArcelorMittal filed a notice of appeal from the district court’s December 4, 2015 final judgment. On May 16, 2017, the Federal Circuit Court of Appeals affirmed the district court’s judgment of invalidity and non-infringement of the reissued Patent. On June 14, 2017, ArcelorMittal filed a petition to the Federal Circuit for rehearing en banc of the May 16, 2017 decision. On August 14, 2017, the Federal Court of Appeals denied ArcelorMittal’s petition for rehearing en banc. On January 20, 2016, we filed a motion to dismiss the amended complaint in the 685 Action, or in the alternative, a motion to stay pending a resolution of the appeal in the original case. On April 19, 2016, the district court issued an order denying our motion and ordering limited discovery. Following discovery, on August 17, 2016, we filed a motion for summary judgment on the basis that the claims in the 685 Action are precluded by the judgment in the original case. On January 19, 2017, the district court issued an opinion granting summary judgment in our favor in the 685 Action on the grounds of non-infringement and also entered a final judgment on that basis. On February 14, 2017, ArcelorMittal filed a notice of appeal of the district court’s order in the Federal Circuit Court of Appeals. The briefing of that appeal is completed and the parties are awaiting a decision from the court. We intend to continue to contest this matter vigorously. We have not made a determination that a loss is probable and we do not have adequate information to reliably or accurately estimate the potential loss if ArcelorMittal prevails in its appeal in this dispute. Because we have been unable to determine that the potential loss in this case is probable or estimable, we have not recorded an accrual for this matter. If our assumptions used to evaluate whether a loss in this matter is either probable or estimable prove to be incorrect or change, we may be required to record a liability for an adverse outcome. Other Contingencies In addition to the matters discussed above, there are various pending and potential claims against us and our subsidiaries involving product liability, commercial, employee benefits and other matters arising in the ordinary course of business. Because of the considerable uncertainties which exist for any claim, it is difficult to reliably or accurately estimate what would be the amount of a loss if a claimant prevails. If material assumptions or factual understandings we rely on to evaluate exposure for these contingencies prove to be inaccurate or otherwise change, we may be required to record a liability for an

Share-based Compensation (Notes

Share-based Compensation (Notes)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	Share-based Compensation AK Holding’s Stock Incentive Plan (“SIP”) permits the granting of nonqualified stock option, restricted stock, performance share and restricted stock unit awards to our Directors, officers and other employees. We have estimated share-based compensation expense to be $9.4 for 2018 . Information on share-based compensation expense is presented below: Three Months Ended September 30, Nine Months Ended September 30, Share-based Compensation Expense 2018 2017 2018 2017 Stock options $ 0.2 $ 0.2 $ 2.2 $ 1.9 Restricted stock 0.5 0.3 2.9 2.6 Restricted stock units issued to Directors 0.3 0.2 0.9 0.9 Performance shares 0.4 0.4 1.5 1.2 Equity-based long-term performance plan 0.1 — 0.3 — Total share-based compensation expense $ 1.5 $ 1.1 $ 7.8 $ 6.6 We granted stock options on 842,000 shares during the nine months ended September 30, 2018 , with a weighted-average fair value of $3.51 per share of stock option. Options on 189,567 shares were exercised during the nine months ended September 30, 2018 . We granted restricted stock awards of 521,100 shares during the nine months ended September 30, 2018 , at a weighted-average fair value of $6.56 per share. The total intrinsic value of restricted stock awards that vested (i.e., restrictions lapsed) during the nine months ended September 30, 2018 was $3.2 . We granted performance share awards of 366,500 shares during the nine months ended September 30, 2018 , with a weighted-average fair value of $8.05 per share. During the first quarter of 2018, in order to further align our management and stockholder interests, the Board of Directors changed how incentive compensation earned by executive officers under the long-term performance plan is paid so that 30% of the compensation earned will now be denominated in stock, instead of all being settled in cash as under prior long-term awards. As a result, starting with the three-year performance period beginning in 2018, the equity-based portion of the long-term performance plan is treated as share-based compensation with a performance condition.

Comprehensive Income (Loss) (No

Comprehensive Income (Loss) (Notes)	9 Months Ended
	Sep. 30, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income (Loss)	Comprehensive Income (Loss) Other comprehensive income (loss), net of tax, information is presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Foreign currency translation Balance at beginning of period $ — $ (1.0 ) $ 1.1 $ (3.6 ) Other comprehensive income (loss)—foreign currency translation gain (loss) (0.3 ) 1.4 (1.4 ) 4.0 Balance at end of period $ (0.3 ) $ 0.4 $ (0.3 ) $ 0.4 Cash flow hedges Balance at beginning of period $ 4.5 $ 21.8 $ 22.3 $ 39.9 Cumulative effect of adopting new hedging standard — — 0.8 — Other comprehensive income (loss): Gains (losses) arising in period (2.3 ) 7.3 (7.8 ) (8.9 ) Income tax expense (benefit) (b) — — — — Gains (losses) arising in period, net of tax (2.3 ) 7.3 (7.8 ) (8.9 ) Reclassification of losses (gains) to net income: Recorded in cost of products sold 0.5 (0.2 ) (12.6 ) (2.1 ) Income tax (expense) benefit (b) — — — — Net amount of reclassification of losses (gains) to net income, net of tax 0.5 (0.2 ) (12.6 ) (2.1 ) Total other comprehensive income (loss), net of tax (1.8 ) 7.1 (20.4 ) (11.0 ) Balance at end of period $ 2.7 $ 28.9 $ 2.7 $ 28.9 Pension and OPEB plans Balance at beginning of period $ (71.3 ) $ (148.7 ) $ (73.6 ) $ (125.0 ) Reclassification to net income: Prior service costs (credits) (a) (2.4 ) (13.6 ) (7.3 ) (40.6 ) Actuarial (gains) losses (a) 3.6 1.6 10.8 4.9 Subtotal 1.2 (12.0 ) 3.5 (35.7 ) Income tax (expense) benefit (b) — — — — Amount of reclassification to net income, net of tax 1.2 (12.0 ) 3.5 (35.7 ) Total other comprehensive income (loss), net of tax 1.2 (12.0 ) 3.5 (35.7 ) Balance at end of period $ (70.1 ) $ (160.7 ) $ (70.1 ) $ (160.7 ) (a) Included in pension and OPEB (income) expense (b)

Earnings Per Share (Notes)

Earnings Per Share (Notes)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share Earnings per share are calculated using the “two-class” method. Under the “two-class” method, undistributed earnings are allocated to both common shares and participating securities. We divide the sum of distributed earnings to common stockholders and undistributed earnings to common stockholders by the weighted-average number of common shares outstanding during the period. The restricted stock granted by AK Holding is entitled to dividends before vesting and meets the criteria of a participating security. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net income (loss) attributable to AK Steel Holding Corporation $ 67.2 $ 22.3 $ 152.5 $ 183.9 Less: distributed earnings to common stockholders and holders of certain stock compensation awards — — — — Undistributed earnings $ 67.2 $ 22.3 $ 152.5 $ 183.9 Common stockholders earnings—basic and diluted: Distributed earnings to common stockholders $ — $ — $ — $ — Undistributed earnings to common stockholders 67.1 22.3 152.3 183.7 Common stockholders earnings—basic and diluted $ 67.1 $ 22.3 $ 152.3 $ 183.7 Common shares outstanding (weighted-average shares in millions): Common shares outstanding for basic earnings per share 314.9 314.3 314.8 314.2 Effect of exchangeable debt — 1.6 — 5.9 Effect of dilutive stock-based compensation 1.1 0.8 1.0 1.0 Common shares outstanding for diluted earnings per share 316.0 316.7 315.8 321.1 Basic earnings per share: Distributed earnings $ — $ — $ — $ — Undistributed earnings 0.21 0.07 0.48 0.58 Basic earnings per share $ 0.21 $ 0.07 $ 0.48 $ 0.58 Diluted earnings per share: Distributed earnings $ — $ — $ — $ — Undistributed earnings 0.21 0.07 0.48 0.57 Diluted earnings per share $ 0.21 $ 0.07 $ 0.48 $ 0.57 Potentially issuable common shares (in millions) excluded from earnings per share calculation due to anti-dilutive effect 2.5 1.5 2.3 1.1

Variable Interest Entities (Not

Variable Interest Entities (Notes)	9 Months Ended
	Sep. 30, 2018
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Variable Interest Entities	Variable Interest Entities SunCoke Middletown We purchase substantially all the coke and electrical power generated from SunCoke Middletown’s plant under long-term supply agreements. SunCoke Middletown is a consolidated variable interest entity because we have committed to purchase all the expected production from the facility through at least 2031 and we are the primary beneficiary. Therefore, we consolidate SunCoke Middletown’s financial results with our financial results, even though we have no ownership interest in SunCoke Middletown. SunCoke Middletown had income before income taxes of $17.8 and $17.1 for the three months ended September 30, 2018 and 2017 , and $49.8 and $48.6 for the nine months ended September 30, 2018 and 2017 , that was included in our consolidated income before income taxes. Vicksmetal/Armco Associates We indirectly own a 50% interest in Vicksmetal/Armco Associates (“VAA”), a joint venture with Vicksmetal Company, which is owned by Sumitomo Corporation. VAA slits electrical steel primarily for us, though it also does so for third parties. VAA is a consolidated variable interest entity and we are the primary beneficiary. Therefore, we consolidate VAA’s financial results with our financial results.

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We measure certain assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e., the “exit price”) in an orderly transaction between market participants at the measurement date. In determining fair value, we use various valuation approaches. The hierarchy of those valuation approaches is broken down into three levels based on the reliability of inputs as follows: • Level 1 inputs are quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date. • Level 2 inputs are inputs, other than quoted prices, that are directly or indirectly observable for the asset or liability. Level 2 inputs include model-generated values that rely on inputs either directly observed or readily-derived from available market data sources, such as Bloomberg or other news and data vendors. They include quoted prices for similar assets or liabilities in active markets, inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates and yield curves observable at commonly quoted intervals or current market) and contractual prices for the underlying financial instrument, as well as other relevant economic factors. As a practical expedient, we estimate the value of money market mutual funds by using a $1.00 per share multiplied by the number of shares in the fund as of the measurement date. We generate fair values for our commodity derivative contracts and foreign currency forward contracts from observable futures prices for the respective commodity or currency, from sources such as the New York Mercantile Exchange (NYMEX) or the London Metal Exchange (LME). We use the Black-Scholes option valuation model to value option contract derivatives (including caps, floors and collars). We use independent sources for implied volatilities, and we discount model-generated future values with discount factors that reflect the counterparty’s credit quality. We apply different discount rates to different contracts since the maturities and counterparties differ. As of September 30, 2018 , a spread over benchmark rates of less than 1% was used for derivatives valued as assets and a spread over benchmark rates of less than 3% was used for derivatives valued as liabilities. We have estimated the fair value of long-term debt based upon quoted market prices for the same or similar issues or on the current interest rates available to us for debt on similar terms and with similar maturities. • Level 3 inputs are unobservable inputs for the asset or liability. Unobservable inputs are used to measure fair value if observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. This level of categorization is not applicable to our valuations on a normal, recurring basis. Assets and liabilities measured at fair value on a recurring basis are presented below: September 30, 2018 December 31, 2017 Level 1 Level 2 Total Level 1 Level 2 Total Assets measured at fair value Cash and cash equivalents $ 47.3 $ — $ 47.3 $ 38.0 $ — $ 38.0 Other current assets: Foreign exchange contracts — 0.4 0.4 — 0.2 0.2 Commodity hedge contracts — 14.7 14.7 — 35.2 35.2 Other non-current assets: Foreign exchange contracts — 1.0 1.0 — 1.7 1.7 Commodity hedge contracts — 2.5 2.5 — 10.6 10.6 Assets measured at fair value $ 47.3 $ 18.6 $ 65.9 $ 38.0 $ 47.7 $ 85.7 Liabilities measured at fair value Accrued liabilities: Foreign exchange contracts $ — $ (0.5 ) $ (0.5 ) $ — $ (0.3 ) $ (0.3 ) Commodity hedge contracts — (3.8 ) (3.8 ) — (4.9 ) (4.9 ) Other non-current liabilities: Foreign exchange contracts — (0.3 ) (0.3 ) — — — Commodity hedge contracts — (1.5 ) (1.5 ) — (0.5 ) (0.5 ) Liabilities measured at fair value $ — $ (6.1 ) $ (6.1 ) $ — $ (5.7 ) $ (5.7 ) Liabilities measured at other than fair value Long-term debt, including current portions: Fair value $ — $ (2,108.7 ) $ (2,108.7 ) $ — $ (2,273.4 ) $ (2,273.4 ) Carrying amount — (2,034.9 ) (2,034.9 ) — (2,110.1 ) (2,110.1 ) The carrying amounts of our other financial instruments do not differ materially from their estimated fair values at September 30, 2018 and December 31, 2017

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities (Notes)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Exchange rate fluctuations affect a portion of revenues and operating costs that are denominated in foreign currencies, and we use forward currency and currency option contracts to reduce our exposure to certain of these currency price fluctuations. Contracts to sell euros have not been designated as cash flow hedges for accounting purposes, and gains or losses are reported in earnings immediately in other (income) expense. Contracts to purchase Canadian dollars are designated as cash flow hedges for accounting purposes, and we record the gains and losses for the derivatives and premiums paid for option contracts in accumulated other comprehensive income (loss) until we reclassify them into cost of products sold when we recognize the associated underlying operating costs. We are exposed to fluctuations in market prices of raw materials and energy sources. We may use cash-settled commodity price swaps and options to hedge the market risk associated with the purchase of certain of our raw materials and energy requirements. For input commodities, these derivatives are typically used for a portion of our electricity, iron ore, natural gas, nickel and zinc requirements. Our hedging strategy is to reduce the effect on earnings from the price volatility of these various commodity exposures, including timing differences between when we incur raw material commodity costs and when we receive sales surcharges from our customers based on those raw materials. Independent of any hedging activities, price changes in any of these commodity markets could negatively affect operating costs. All commodity derivatives are recognized as an asset or liability at fair value. We record the gains and losses and premiums paid for option contracts for commodity derivatives designated as cash flow hedges of forecasted purchases of raw materials and energy sources in accumulated other comprehensive income (loss) and reclassify them into cost of products sold when we recognize earnings for the associated underlying transaction. We record all gains or losses from commodity derivatives for which hedge accounting treatment has not been elected to earnings immediately in cost of products sold. We have provided no collateral to counterparties under collateral funding arrangements as of September 30, 2018 . Outstanding derivative contracts and the period over which we are hedging our exposure to the volatility in future cash flows are presented below: Derivative Contracts Settlement Dates September 30, December 31, Commodity contracts: Nickel (in lbs) — 500,000 Natural gas (in MMBTUs) October 2018 to October 2020 36,978,000 41,338,000 Zinc (in lbs) October 2018 to September 2020 42,300,000 50,350,000 Iron ore (in metric tons) October 2018 to May 2020 1,965,000 2,340,000 Electricity (in MWHs) October 2018 to June 2020 1,337,000 1,553,000 Foreign exchange contracts: Euros (in millions) October 2018 to December 2018 € 4.5 € 26.0 Canadian dollars (in millions) October 2018 to December 2021 C$ 133.1 C$ 148.1 The fair value of derivative instruments in the condensed consolidated balance sheets is presented below: Asset (liability) September 30, December 31, Derivatives designated as cash flow hedges: Other current assets: Foreign exchange contracts $ 0.2 $ 0.2 Commodity contracts 3.5 9.0 Other non-current assets: Foreign exchange contracts 1.0 1.7 Commodity contracts 0.2 2.3 Accrued liabilities: Foreign exchange contracts (0.5 ) (0.2 ) Commodity contracts (3.8 ) (4.6 ) Other non-current liabilities: Foreign exchange contracts (0.3 ) — Commodity contracts (1.5 ) (0.5 ) Derivatives not designated as cash flow hedges: Other current assets: Foreign exchange contracts 0.2 — Commodity contracts 11.2 26.2 Other non-current assets—commodity contracts 2.3 8.3 Accrued liabilities: Foreign exchange contracts — (0.1 ) Commodity contracts — (0.3 ) Gains (losses) on derivative instruments included in the condensed consolidated statements of operations and comprehensive income (loss) are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Gain (loss) Derivatives designated as cash flow hedges: Commodity contracts: Recognized in accumulated other comprehensive income that were included in the assessment of effectiveness $ (3.1 ) $ 7.3 $ (5.4 ) $ (8.9 ) Reclassified from accumulated other comprehensive income into cost of products sold 0.1 0.2 13.1 2.1 Foreign exchange contracts: Recognized in accumulated other comprehensive income that were included in the assessment of effectiveness 0.8 — (2.4 ) — Reclassified from accumulated other comprehensive income into cost of products sold (0.6 ) — (0.5 ) — Derivatives not designated as cash flow hedges: Commodity contracts—recognized in cost of products sold 4.5 3.9 (1.9 ) 11.0 Foreign exchange contracts—recognized in other income (expense) (0.1 ) (0.1 ) 0.3 (0.8 ) We routinely use iron ore derivatives to reduce the volatility of the cost of our iron ore purchases. These derivatives do not qualify for hedge accounting treatment. Therefore, adjustments to mark these derivatives to fair value each period are recognized immediately in our financial results versus being recognized in the period that iron ore purchases affect earnings. For the three and nine months ended September 30, 2018 , gains (losses) recognized in cost of products sold shown in the table above include $4.4 and $(1.2) for unrealized mark-to-market gains (losses) on iron ore derivatives. Gains (losses) recognized in cost of products sold shown in the table above for unrealized mark-to-market gains (losses) on iron ore derivatives for the corresponding periods in 2017 include $4.0 and $11.9 . Not included in the financial results for the three and nine months ended September 30, 2018 , were realized gains of $5.7 and $17.2 for iron ore derivatives contracts that settled during the period for which we had recognized mark-to-market gains in our financial results in prior quarters, compared to $9.3 and $29.6 for the same periods in 2017 . Gains (losses) before tax expected to be reclassified into cost of products sold within the next twelve months for our existing derivatives that qualify as cash flow hedges for hedge accounting are presented below: Hedge Gains (losses) Natural gas $ (0.1 ) Zinc (5.2 ) Electricity 2.7 Canadian dollars (1.3 )

Supplementary Cash Flow Informa

Supplementary Cash Flow Information (Notes)	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Supplementary Cash Flow Information	Supplementary Cash Flow Information Net cash paid (received) during the period for interest, net of capitalized interest, and income taxes are presented below: Nine Months Ended September 30, 2018 2017 Net cash paid (received) during the period for: Interest, net of capitalized interest $ 100.7 $ 101.1 Income taxes (5.7 ) (0.2 ) Included in net cash flows from operations was cash provided by SunCoke Middletown of $60.4 and $59.2 for the nine months ended September 30, 2018 and 2017 . Consolidated cash and cash equivalents at September 30, 2018 and December 31, 2017 , include SunCoke Middletown’s cash and cash equivalents of $5.2 and $0.1 . SunCoke Middletown’s cash and cash equivalents have no compensating balance arrangements or legal restrictions, but are not available for our use. We had capital investments during the nine months ended September 30, 2018 and 2017 that had not been paid as of the end of the respective period. These amounts are included in accounts payable and accrued liabilities and have been excluded from the condensed consolidated statements of cash flows until paid. We also grant restricted stock to certain employees and restricted stock units to directors under the SIP. Non-cash investing and financing activities are presented below: Nine Months Ended September 30, 2018 2017 Capital investments $ 25.6 $ 29.0 Issuance of restricted stock and restricted stock units 4.3 4.3

Union Contracts (Notes)

Union Contracts (Notes)	9 Months Ended
	Sep. 30, 2018
Union Contracts [Abstract]
Union Contracts	Union Contracts In March 2018, members of the International Association of Machinists and Aerospace Workers, Local 1943 , ratified a labor agreement covering approximately 1,750 production employees at Middletown Works. The new agreement expires March 15, 2020 . In October 2018, we and the United Steelworkers, Local 1865 , which represents approximately 240 production employees at Ashland Works, agreed to a rolling 60-day extension of the current labor agreement that was previously extended to November 1, 2018 , two months from its original September 1, 2018 expiration. An agreement with the United Steelworkers, Local 1190 , which governs approximately 220 production employees at Mountain State Carbon LLC, is scheduled to expire on March 1, 2019 . An agreement with the United Auto Workers, Local 3303 , which governs approximately 1,180 production employees at Butler Works, is scheduled to expire on April 1, 2019 . An agreement with the United Auto Workers, Local 4104 , which governs approximately 100 production employees at Zanesville Works, is scheduled to expire on May 31, 2019 . An agreement with the United Auto Workers, Local 3462 , which governs approximately 310 production employees at Coshocton Works, is scheduled to expire on September 30, 2019

New Accounting Pronouncements (

New Accounting Pronouncements (Notes)	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles	New Accounting Pronouncements Other Recent Accounting Pronouncements Adopted We adopted Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) , as of January 1, 2018 through the modified retrospective method applied to those contracts that were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under ASC Topic 605. There was no adjustment required to adopt Topic 606 since our revenue recognition under Topic 606 is substantially the same as under Topic 605. In August 2017, the FASB issued Accounting Standards Update 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities , to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. Among other amendments, the update allows entities to designate the variability in cash flows attributable to changes in a contractually specified component stated in the contract as the hedged risk in a cash flow hedge of a forecasted purchase or sale of a nonfinancial asset. We have adopted the standard update effective as of January 1, 2018, and have applied the new hedge guidance for certain hedges entered since adoption. The effect of adoption of the new guidance was not significant. Recent Accounting Pronouncements Not Yet Adopted FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) , during the first quarter of 2016. Topic 842 requires entities to recognize lease assets and lease liabilities, with the exception of short-term leases, and disclose key information about leasing arrangements for certain leases. We intend to recognize and measure leases beginning at the adoption date using a modified retrospective approach. Topic 842 is effective for us beginning January 1, 2019. We are currently evaluating the effect of the adoption of Topic 842 on our consolidated financial position and results of operations. We expect that the adoption of the standard will result in a material increase to the assets and liabilities on our consolidated balance sheets. We have formed an implementation team, identified our lease population and are implementing new software to manage our leases and account for them under the new standard. We plan to elect the transition package of practical expedients permitted within the new standard, which among other things, will allow us to carry forward historical lease classifications. We plan to make an accounting election that does not require us to recognize a lease liability or right-of-use asset for short-term leases. We continue to evaluate the accounting treatment of identified contracts, including service agreements. In June 2016, FASB issued Accounting Standards Update 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , to replace the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In connection with recognizing credit losses on receivables and other financial instruments, we will be required to use a forward-looking expected loss model rather than the incurred loss model. The new standard will be effective for us beginning January 1, 2020, with early adoption permitted beginning January 1, 2019. Adoption of this standard is through a cumulative-effect adjustment to retained earnings as of the effective date. We are currently evaluating the effect of this standard on our consolidated financial position and results of operations. In February 2018, FASB issued Accounting Standards Update 2018-02, Income Statement—Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

Supplementary Guarantor Informa

Supplementary Guarantor Information (Notes)	9 Months Ended
	Sep. 30, 2018
Supplemental Guarantor Information [Abstract]
Supplementary Guarantor Information	Supplementary Guarantor Information AK Steel’s senior secured notes due 2023 and senior unsecured notes due 2021, 2025 and 2027 (collectively, the “Senior Notes”) and its Exchangeable Notes due 2019 are governed by indentures entered into by AK Holding and its 100%-owned subsidiary, AK Steel. Under the terms of the Senior Notes’ indentures, AK Holding and certain subsidiary guarantors each fully and unconditionally, jointly and severally, guarantee the payment of interest, principal and premium, if any, on each of the notes included in the Senior Notes. Under the terms of the indenture for the Exchangeable Notes, AK Holding fully and unconditionally, jointly and severally, guarantees the payment of interest, principal and premium, if any, on the Exchangeable Notes. AK Holding is the sole guarantor of the Exchangeable Notes. We present all investments in subsidiaries in the supplementary guarantor information using the equity method of accounting. Therefore, the net income (loss) of the subsidiaries accounted for using the equity method is in their parents’ investment accounts. The principal elimination entries eliminate investments in subsidiaries and inter-company balances and transactions. The following supplementary condensed consolidating financial statements present information about AK Holding, AK Steel, the subsidiary guarantors of the Senior Notes and the other non-guarantor subsidiaries. Condensed Consolidated Statements of Comprehensive Income (Loss) Three Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 1,602.0 $ 81.0 $ 179.0 $ (126.4 ) $ 1,735.6 Cost of products sold (exclusive of item shown separately below) — 1,401.3 54.8 145.7 (115.6 ) 1,486.2 Selling and administrative expenses 0.7 79.6 3.6 8.8 (13.1 ) 79.6 Depreciation — 43.8 2.0 9.2 — 55.0 Total operating costs 0.7 1,524.7 60.4 163.7 (128.7 ) 1,620.8 Operating profit (loss) (0.7 ) 77.3 20.6 15.3 2.3 114.8 Interest expense — 36.4 — 1.4 — 37.8 Pension and OPEB (income) expense — (10.0 ) — — — (10.0 ) Other (income) expense — 0.6 (4.3 ) (0.4 ) 4.8 0.7 Income (loss) before income taxes (0.7 ) 50.3 24.9 14.3 (2.5 ) 86.3 Income tax expense (benefit) — (3.9 ) 6.2 (0.3 ) (0.6 ) 1.4 Equity in net income (loss) of subsidiaries 67.9 13.7 — 0.5 (82.1 ) — Net income (loss) 67.2 67.9 18.7 15.1 (84.0 ) 84.9 Less: Net income attributable to noncontrolling interests — — — 17.7 — 17.7 Net income (loss) attributable to AK Steel Holding Corporation 67.2 67.9 18.7 (2.6 ) (84.0 ) 67.2 Other comprehensive income (loss) (0.9 ) (0.9 ) — (0.3 ) 1.2 (0.9 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 66.3 $ 67.0 $ 18.7 $ (2.9 ) $ (82.8 ) $ 66.3 Condensed Consolidated Statements of Comprehensive Income (Loss) Three Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 1,406.0 $ 71.3 $ 139.7 $ (122.7 ) $ 1,494.3 Cost of products sold (exclusive of item shown separately below) — 1,253.2 50.1 112.2 (113.7 ) 1,301.8 Selling and administrative expenses 0.9 69.2 3.1 6.1 (11.1 ) 68.2 Depreciation — 47.2 2.1 8.7 — 58.0 Total operating costs 0.9 1,369.6 55.3 127.0 (124.8 ) 1,428.0 Operating profit (loss) (0.9 ) 36.4 16.0 12.7 2.1 66.3 Interest expense — 37.1 — 0.4 — 37.5 Pension and OPEB (income) expense — (18.1 ) — — — (18.1 ) Other (income) expense — 13.1 (3.1 ) (2.2 ) — 7.8 Income (loss) before income taxes (0.9 ) 4.3 19.1 14.5 2.1 39.1 Income tax expense (benefit) — (6.3 ) 7.2 (1.9 ) 0.7 (0.3 ) Equity in net income (loss) of subsidiaries 23.2 12.6 — 0.2 (36.0 ) — Net income (loss) 22.3 23.2 11.9 16.6 (34.6 ) 39.4 Less: Net income attributable to noncontrolling interests — — — 17.1 — 17.1 Net income (loss) attributable to AK Steel Holding Corporation 22.3 23.2 11.9 (0.5 ) (34.6 ) 22.3 Other comprehensive income (loss) (3.5 ) (3.5 ) — 1.4 2.1 (3.5 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 18.8 $ 19.7 $ 11.9 $ 0.9 $ (32.5 ) $ 18.8 Condensed Consolidated Statements of Comprehensive Income (Loss) Nine Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 4,704.3 $ 242.5 $ 582.8 $ (388.5 ) $ 5,141.1 Cost of products sold (exclusive of item shown separately below) — 4,168.1 166.8 477.1 (349.4 ) 4,462.6 Selling and administrative expenses 2.8 233.2 11.0 26.5 (37.7 ) 235.8 Depreciation — 130.6 6.0 28.2 — 164.8 Total operating costs 2.8 4,531.9 183.8 531.8 (387.1 ) 4,863.2 Operating profit (loss) (2.8 ) 172.4 58.7 51.0 (1.4 ) 277.9 Interest expense — 109.3 — 4.0 — 113.3 Pension and OPEB expense (income) — (30.0 ) — — — (30.0 ) Other (income) expense — 6.4 (11.8 ) (2.8 ) 4.8 (3.4 ) Income (loss) before income taxes (2.8 ) 86.7 70.5 49.8 (6.2 ) 198.0 Income tax expense (benefit) — (21.8 ) 17.6 1.7 (1.5 ) (4.0 ) Equity in net income (loss) of subsidiaries 155.3 46.8 — 0.7 (202.8 ) — Net income (loss) 152.5 155.3 52.9 48.8 (207.5 ) 202.0 Less: Net income attributable to noncontrolling interests — — — 49.5 — 49.5 Net income (loss) attributable to AK Steel Holding Corporation 152.5 155.3 52.9 (0.7 ) (207.5 ) 152.5 Other comprehensive income (loss) (18.3 ) (18.3 ) — (1.4 ) 19.7 (18.3 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 134.2 $ 137.0 $ 52.9 $ (2.1 ) $ (187.8 ) $ 134.2 Condensed Consolidated Statements of Comprehensive Income (Loss) Nine Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 4,378.0 $ 217.7 $ 329.0 $ (339.8 ) $ 4,584.9 Cost of products sold (exclusive of item shown separately below) — 3,809.2 149.8 246.1 (306.4 ) 3,898.7 Selling and administrative expenses 3.3 210.3 9.5 16.4 (34.0 ) 205.5 Depreciation — 141.3 6.2 20.7 — 168.2 Total operating costs 3.3 4,160.8 165.5 283.2 (340.4 ) 4,272.4 Operating profit (loss) (3.3 ) 217.2 52.2 45.8 0.6 312.5 Interest expense — 114.0 — 1.1 — 115.1 Pension and OPEB expense (income) — (54.3 ) — — — (54.3 ) Other (income) expense — 32.3 (8.3 ) (4.8 ) — 19.2 Income (loss) before income taxes (3.3 ) 125.2 60.5 49.5 0.6 232.5 Income tax expense (benefit) — (22.4 ) 23.0 (0.6 ) 0.1 0.1 Equity in net income (loss) of subsidiaries 187.2 39.6 — 0.1 (226.9 ) — Net income (loss) 183.9 187.2 37.5 50.2 (226.4 ) 232.4 Less: Net income attributable to noncontrolling interests — — — 48.5 — 48.5 Net income (loss) attributable to AK Steel Holding Corporation 183.9 187.2 37.5 1.7 (226.4 ) 183.9 Other comprehensive income (loss) (42.7 ) (42.7 ) — 4.0 38.7 (42.7 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 141.2 $ 144.5 $ 37.5 $ 5.7 $ (187.7 ) $ 141.2 Condensed Consolidated Balance Sheets September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company ASSETS Current assets: Cash and cash equivalents $ — $ 25.2 $ 2.2 $ 19.9 $ — $ 47.3 Accounts receivable, net — 562.6 38.5 112.4 (12.8 ) 700.7 Inventory — 1,221.0 60.0 75.9 (11.4 ) 1,345.5 Other current assets — 70.0 0.2 8.7 — 78.9 Total current assets — 1,878.8 100.9 216.9 (24.2 ) 2,172.4 Property, plant and equipment — 6,072.7 185.2 658.2 — 6,916.1 Accumulated depreciation — (4,749.1 ) (100.7 ) (157.2 ) — (5,007.0 ) Property, plant and equipment, net — 1,323.6 84.5 501.0 — 1,909.1 Investment in subsidiaries (3,056.2 ) 1,913.4 — 68.2 1,074.6 — Inter-company accounts 3,153.3 — 1,605.7 — (4,759.0 ) — Other non-current assets — 56.9 32.9 316.6 — 406.4 TOTAL ASSETS $ 97.1 $ 5,172.7 $ 1,824.0 $ 1,102.7 $ (3,708.6 ) $ 4,487.9 LIABILITIES AND EQUITY Current liabilities: Accounts payable $ — $ 699.2 $ 21.8 $ 56.7 $ (4.1 ) $ 773.6 Accrued liabilities — 219.8 7.6 29.9 — 257.3 Current portion of pension and other postretirement benefit obligations — 38.4 — 0.4 — 38.8 Total current liabilities — 957.4 29.4 87.0 (4.1 ) 1,069.7 Non-current liabilities: Long-term debt — 2,034.9 — — — 2,034.9 Pension and other postretirement benefit obligations — 794.3 — 3.2 — 797.5 Inter-company accounts — 4,326.8 — 511.2 (4,838.0 ) — Other non-current liabilities — 115.5 — 32.5 — 148.0 TOTAL LIABILITIES — 8,228.9 29.4 633.9 (4,842.1 ) 4,050.1 Equity: Total stockholders’ equity (deficit) 97.1 (3,056.2 ) 1,794.6 128.1 1,133.5 97.1 Noncontrolling interests — — — 340.7 — 340.7 TOTAL EQUITY 97.1 (3,056.2 ) 1,794.6 468.8 1,133.5 437.8 TOTAL LIABILITIES AND EQUITY $ 97.1 $ 5,172.7 $ 1,824.0 $ 1,102.7 $ (3,708.6 ) $ 4,487.9 Condensed Consolidated Balance Sheets December 31, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company ASSETS Current assets: Cash and cash equivalents $ — $ 14.5 $ 7.2 $ 16.3 $ — $ 38.0 Accounts receivable, net — 432.4 33.2 65.4 (13.2 ) 517.8 Inventory — 1,231.5 55.1 108.3 (9.9 ) 1,385.0 Other current assets — 124.7 0.2 5.4 — 130.3 Total current assets — 1,803.1 95.7 195.4 (23.1 ) 2,071.1 Property, plant and equipment — 6,004.0 181.5 646.3 — 6,831.8 Accumulated depreciation — (4,620.8 ) (94.8 ) (130.0 ) — (4,845.6 ) Property, plant and equipment, net — 1,383.2 86.7 516.3 — 1,986.2 Investment in subsidiaries (3,127.4 ) 1,844.9 — 67.5 1,215.0 — Inter-company accounts 3,082.8 — 1,523.1 — (4,605.9 ) — Other non-current assets — 66.3 33.0 318.2 — 417.5 TOTAL ASSETS $ (44.6 ) $ 5,097.5 $ 1,738.5 $ 1,097.4 $ (3,414.0 ) $ 4,474.8 LIABILITIES AND EQUITY Current liabilities: Accounts payable $ — $ 623.3 $ 17.9 $ 50.9 $ (1.7 ) $ 690.4 Accrued liabilities — 228.2 7.8 34.5 — 270.5 Current portion of pension and other postretirement benefit obligations — 39.7 — 0.4 — 40.1 Total current liabilities — 891.2 25.7 85.8 (1.7 ) 1,001.0 Non-current liabilities: Long-term debt — 2,110.1 — — — 2,110.1 Pension and other postretirement benefit obligations — 890.8 — 3.4 — 894.2 Inter-company accounts — 4,199.6 — 489.1 (4,688.7 ) — Other non-current liabilities — 133.2 1.0 34.7 — 168.9 TOTAL LIABILITIES — 8,224.9 26.7 613.0 (4,690.4 ) 4,174.2 Equity: Total stockholders’ equity (deficit) (44.6 ) (3,127.4 ) 1,711.8 139.2 1,276.4 (44.6 ) Noncontrolling interests — — — 345.2 — 345.2 TOTAL EQUITY (44.6 ) (3,127.4 ) 1,711.8 484.4 1,276.4 300.6 TOTAL LIABILITIES AND EQUITY $ (44.6 ) $ 5,097.5 $ 1,738.5 $ 1,097.4 $ (3,414.0 ) $ 4,474.8 Condensed Consolidated Statements of Cash Flows Nine Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net cash flows from operating activities $ (2.1 ) $ 133.1 $ 47.6 $ 65.3 $ 6.0 $ 249.9 Cash flows from investing activities: Capital investments — (82.6 ) (3.7 ) (14.8 ) — (101.1 ) Other investing items, net — 0.7 — (0.5 ) — 0.2 Net cash flows from investing activities — (81.9 ) (3.7 ) (15.3 ) — (100.9 ) Cash flows from financing activities: Net borrowings (payments) under credit facility — (85.0 ) — — — (85.0 ) Inter-company activity 2.4 44.9 (48.9 ) 7.6 (6.0 ) — SunCoke Middletown distributions to noncontrolling interest owners — — — (54.0 ) — (54.0 ) Other financing items, net (0.3 ) (0.4 ) — — — (0.7 ) Net cash flows from financing activities 2.1 (40.5 ) (48.9 ) (46.4 ) (6.0 ) (139.7 ) Net increase (decrease) in cash and cash equivalents — 10.7 (5.0 ) 3.6 — 9.3 Cash and equivalents, beginning of period — 14.5 7.2 16.3 — 38.0 Cash and equivalents, end of period $ — $ 25.2 $ 2.2 $ 19.9 $ — $ 47.3 Condensed Consolidated Statements of Cash Flows Nine Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net cash flows from operating activities $ (2.4 ) $ 55.9 $ 30.6 $ 64.8 $ 5.1 $ 154.0 Cash flows from investing activities: Capital investments — (78.5 ) (4.6 ) (5.6 ) — (88.7 ) Investment in acquired business, net of cash acquired — (360.9 ) — — — (360.9 ) Other investing items, net — 4.3 — (0.1 ) — 4.2 Net cash flows from investing activities — (435.1 ) (4.6 ) (5.7 ) — (445.4 ) Cash flows from financing activities: Net borrowings (payments) under credit facility — 415.0 — — — 415.0 Proceeds from issuance of long-term debt — 680.0 — — — 680.0 Redemption of long-term debt — (821.8 ) — — — (821.8 ) Debt issuance costs — (25.0 ) — — — (25.0 ) Inter-company activity 4.9 10.1 (24.5 ) 14.6 (5.1 ) — SunCoke Middletown distributions to noncontrolling interest owners — — — (58.2 ) — (58.2 ) Other financing items, net (2.5 ) — — — — (2.5 ) Net cash flows from financing activities 2.4 258.3 (24.5 ) (43.6 ) (5.1 ) 187.5 Net increase (decrease) in cash and cash equivalents — (120.9 ) 1.5 15.5 — (103.9 ) Cash and equivalents, beginning of period — 147.9 4.4 20.9 — 173.2 Cash and equivalents, end of period $ — $ 27.0 $ 5.9 $ 36.4 $ — $ 69.3

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting, Policy	Basis of Presentation— These financial statements consolidate the operations and accounts of AK Steel Holding Corporation (“AK Holding”), its wholly-owned subsidiary AK Steel Corporation (“AK Steel”), all subsidiaries in which AK Holding has a controlling interest, and two variable interest entities for which AK Steel is the primary beneficiary. Unless the context provides otherwise, references to “we,” “us” and “our” refer to AK Holding and its subsidiaries. In our opinion, the accompanying condensed consolidated financial statements contain all adjustments, consisting of normal recurring adjustments, necessary to present fairly our financial position as of September 30, 2018 and December 31, 2017 , our results of operations for the three and nine months ended September 30, 2018 and 2017 , and our cash flows for the nine months ended September 30, 2018 and 2017 . Our results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results we expect for the full year ending December 31, 2018 . These condensed consolidated financial statements should be read along with our audited consolidated financial statements for the year ended December 31, 2017 , included in our Annual Report on Form 10-K for the year ended December 31, 2017
Revenue Recognition, Policy	Revenue Recognition— We generate our revenue through product sales, and shipping terms generally indicate when we have fulfilled our performance obligations and passed control of products to our customer. Our revenue transactions consist of a single performance obligation to transfer promised goods. We have contracts with a substantial portion of our customers. These contracts usually define the mechanism for determining the sales price, but the contacts do not impose a specific quantity on either party. Quantities to be delivered to the customer are determined at a point near the date of delivery through purchase orders or other written instructions we receive from the customer. Spot market sales are made through purchase orders or other written instructions. We recognize revenue when we have fulfilled a performance obligation, which is typically when we have shipped products at the customer’s instructions. For sales with shipping terms that transfer title and risk of loss at the destination point, we recognize revenue when the customer receives the goods and our performance obligation is complete. For sales with shipping terms that transfer title and risk of loss at the shipping point with us bearing responsibility for freight costs to the destination, we determine that we have fulfilled a single performance obligation and recognize revenue when we ship the goods. For our tooling solutions, we record progress payments that we receive from a customer as accrued liabilities until we recognize the revenue when the customer provides written acceptance that our performance obligation has been fulfilled.
Inventory, Policy	Inventory— Inventories are valued at the lower of cost or net realizable value. We measure the cost of inventories using the average cost method. See Note 3
Accounting Changes, Policy	Pension and Other Postretirement Benefits— On January 1, 2018, we adopted Accounting Standards Update No. 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . Under this standard, the service cost component of periodic pension and other postretirement benefit expense is included in cost of products sold and selling and administrative expenses, consistent with our treatment of other employee compensation costs. The remainder of periodic pension and other postretirement benefit income of $10.0 and $18.1 for the three months ended September 30, 2018 and 2017 and $30.0 and $54.3 for the nine months ended September 30, 2018 and 2017

Earnings Per Share (Policies)

Earnings Per Share (Policies)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share, Policy	Earnings per share are calculated using the “two-class” method. Under the “two-class” method, undistributed earnings are allocated to both common shares and participating securities. We divide the sum of distributed earnings to common stockholders and undistributed earnings to common stockholders by the weighted-average number of common shares outstanding during the period. The restricted stock granted by AK Holding is entitled to dividends before vesting and meets the criteria of a participating security.

Supplementary Financial State_2

Supplementary Financial Statement Information (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Disaggregation of Revenue	Net sales by market are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Automotive $ 1,036.7 $ 948.8 $ 3,264.5 $ 2,986.0 Infrastructure and Manufacturing 277.1 239.3 782.2 717.9 Distributors and Converters 421.8 306.2 1,094.4 881.0 Total $ 1,735.6 $ 1,494.3 $ 5,141.1 $ 4,584.9 Net sales by product line are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Carbon steel $ 1,132.6 $ 995.7 $ 3,303.6 $ 3,073.0 Stainless and electrical steel 454.3 401.2 1,363.5 1,279.2 Tubular products, components and other 148.7 97.4 474.0 232.7 Total $ 1,735.6 $ 1,494.3 $ 5,141.1 $ 4,584.9
Inventory	Inventories as of September 30, 2018 and December 31, 2017 , are presented below: September 30, December 31, Finished and semi-finished $ 1,014.4 $ 996.8 Raw materials 331.1 388.2 Inventory $ 1,345.5 $ 1,385.0
Schedule of Changes in Accounting Principles	As a result of the retrospective application of the change in accounting principle, certain financial statement line items in our condensed consolidated balance sheet as of December 31, 2017 and our condensed consolidated statements of operations and comprehensive income and cash flows for the three and nine months ended September 30, 2017 were adjusted as follows: As Originally Reported Effect of Change As Adjusted Condensed consolidated statement of operations for the three months ended September 30, 2017: Cost of products sold (a) $ 1,348.4 $ (46.6 ) $ 1,301.8 Income tax expense (benefit) (18.8 ) 18.5 (0.3 ) Net income 11.3 28.1 39.4 Net income attributable to AK Steel Holding Corporation (5.8 ) 28.1 22.3 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ (0.02 ) $ 0.09 $ 0.07 Diluted (0.02 ) 0.09 0.07 Condensed consolidated statement of operations for the nine months ended September 30, 2017: Cost of products sold (a) $ 4,005.7 $ (107.0 ) $ 3,898.7 Income tax expense (benefit) (40.9 ) 41.0 0.1 Net income 166.4 66.0 232.4 Net income attributable to AK Steel Holding Corporation 117.9 66.0 183.9 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.37 $ 0.21 $ 0.58 Diluted 0.37 0.20 0.57 Condensed consolidated statement of comprehensive income for the three months ended September 30, 2017: Cash flow hedges—Reclassification of losses (gains) to net income $ (1.9 ) $ 1.7 $ (0.2 ) Comprehensive income 6.1 29.8 35.9 Comprehensive income attributable to AK Steel Holding Corporation (11.0 ) 29.8 18.8 Condensed consolidated statement of comprehensive income for the nine months ended September 30, 2017: Cash flow hedges—Reclassification of losses (gains) to net income $ (7.2 ) $ 5.1 $ (2.1 ) Comprehensive income 118.6 71.1 189.7 Comprehensive income attributable to AK Steel Holding Corporation 70.1 71.1 141.2 Condensed consolidated balance sheet as of December 31, 2017: Inventory $ 1,147.8 $ 237.2 $ 1,385.0 Other non-current assets 476.0 (58.5 ) 417.5 Other non-current liabilities 161.6 7.3 168.9 Accumulated deficit (3,058.6 ) 181.6 (2,877.0 ) Accumulated other comprehensive loss (40.0 ) (10.2 ) (50.2 ) As Originally Reported Effect of Change As Adjusted Condensed consolidated statement of cash flows for the nine months ended September 30, 2017: Net income $ 166.4 $ 66.0 $ 232.4 Deferred income taxes (36.1 ) 41.0 4.9 Changes in working capital (44.1 ) (112.1 ) (156.2 ) Other operating items, net (1.6 ) 5.1 3.5 (a) Cost of products sold as originally reported reflects the change in presentation of pension and OPEB (income) expense further described in Note 1 . The following table shows the effects of the change in accounting principle from LIFO to average cost as of September 30, 2018 and for the three and nine months ended September 30, 2018 : As Computed under LIFO As Reported under Average Cost Effect of Change Condensed consolidated statement of operations for the three months ended September 30, 2018: Cost of products sold $ 1,499.7 $ 1,486.2 $ (13.5 ) Income tax expense (benefit) (1.9 ) 1.4 3.3 Net income 74.7 84.9 10.2 Net income attributable to AK Steel Holding Corporation 57.0 67.2 10.2 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.18 $ 0.21 $ 0.03 Diluted 0.18 0.21 0.03 Condensed consolidated statement of operations for the nine months ended September 30, 2018: Cost of products sold $ 4,504.8 $ 4,462.6 $ (42.2 ) Income tax expense (benefit) (13.9 ) (4.0 ) 9.9 Net income 169.7 202.0 32.3 Net income attributable to AK Steel Holding Corporation 120.2 152.5 32.3 Net income per share attributable to AK Steel Holding Corporation common stockholders: Basic $ 0.38 $ 0.48 $ 0.10 Diluted 0.38 0.48 0.10 Condensed consolidated statement of comprehensive income for the three months ended September 30, 2018: Comprehensive income $ 73.8 $ 84.0 $ 10.2 Comprehensive income attributable to AK Steel Holding Corporation 56.1 66.3 10.2 Condensed consolidated statement of comprehensive income for the nine months ended September 30, 2018: Comprehensive income $ 151.4 $ 183.7 $ 32.3 Comprehensive income attributable to AK Steel Holding Corporation 101.9 134.2 32.3 Condensed consolidated balance sheet as of September 30, 2018: Inventory $ 1,067.8 $ 1,345.5 $ 277.7 Other non-current assets 480.1 406.4 (73.7 ) Other non-current liabilities 146.0 148.0 2.0 Accumulated deficit (2,939.2 ) (2,725.3 ) 213.9 Condensed consolidated statement of cash flows for the nine months ended September 30, 2018: Net income $ 169.7 $ 202.0 $ 32.3 Deferred income taxes (16.2 ) (6.3 ) 9.9 Changes in working capital 29.4 (11.1 ) (40.5 ) Other operating items, net (28.9 ) (30.6 ) (1.7 )
Schedule of Goodwill	The change in goodwill for the nine months ended September 30, 2018 , was as follows. 2018 Balance at beginning of period $ 253.8 Adjustment to acquisition purchase price 1.2 Balance at end of period $ 255.0
Schedule of Intangible Assets	Intangible assets at September 30, 2018 and December 31, 2017 , consist of: Gross Amount Accumulated Amortization Net Amount As of September 30, 2018 Customer relationships $ 36.6 $ (6.1 ) $ 30.5 Technology 19.3 (3.8 ) 15.5 Other 1.0 (1.0 ) — Intangible assets $ 56.9 $ (10.9 ) $ 46.0 As of December 31, 2017 Customer relationships $ 36.6 $ (2.2 ) $ 34.4 Technology 19.3 (1.4 ) 17.9 Other 1.0 (0.4 ) 0.6 Intangible assets $ 56.9 $ (4.0 ) $ 52.9
Investments in Affiliates	Summarized financial statement data for all investees is presented below. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenue $ 88.9 $ 73.2 $ 247.2 $ 222.5 Gross profit 24.5 20.5 69.2 69.6 Net income 6.4 3.4 15.7 18.8 Our share of income of equity investees (included in cost of products sold) 2.5 1.0 5.5 6.6

Long-term Debt and Other Fina_2

Long-term Debt and Other Financing (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Debt balances at September 30, 2018 and December 31, 2017 , are presented below: September 30, December 31, Credit Facility $ 365.0 $ 450.0 7.50% Senior Secured Notes due July 2023 (effective rate of 8.3%) 380.0 380.0 5.00% Exchangeable Senior Notes due November 2019 (effective rate of 10.8%) 150.0 150.0 7.625% Senior Notes due October 2021 406.2 406.2 6.375% Senior Notes due October 2025 (effective rate of 7.1%) 280.0 280.0 7.00% Senior Notes due March 2027 400.0 400.0 Industrial Revenue Bonds due 2020 through 2028 99.3 99.3 Unamortized debt discount and issuance costs (45.6 ) (55.4 ) Total long-term debt $ 2,034.9 $ 2,110.1

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2018
Retirement Benefits, Description [Abstract]
Schedule of Defined Benefit Plans Disclosures	Net periodic benefit (income) expense for pension and other postretirement benefits was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Pension Benefits Service cost $ 0.9 $ 0.7 $ 2.4 $ 2.1 Interest cost 23.7 27.0 71.2 81.0 Expected return on assets (38.8 ) (37.5 ) (116.4 ) (112.6 ) Amortization of prior service cost 1.0 1.1 2.9 3.4 Amortization of loss 3.9 2.7 11.8 8.1 Net periodic benefit (income) expense $ (9.3 ) $ (6.0 ) $ (28.1 ) $ (18.0 ) Other Postretirement Benefits Service cost $ 1.1 $ 1.2 $ 3.4 $ 3.5 Interest cost 3.9 4.4 11.7 13.1 Amortization of prior service cost (credit) (3.4 ) (14.7 ) (10.2 ) (44.0 ) Amortization of (gain) loss (0.3 ) (1.1 ) (1.0 ) (3.2 ) Net periodic benefit (income) expense $ 1.3 $ (10.2 ) $ 3.9 $ (30.6 )

Environmental and Legal Conti_2

Environmental and Legal Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Accrual of Liabilities Related to Environmental Loss Contingencies	We have recorded the following liabilities for environmental matters on our condensed consolidated balance sheets: September 30, December 31, Accrued liabilities $ 8.0 $ 8.5 Other non-current liabilities 30.2 35.4
Schedule of Information on Pending Asbestos Cases	The number of asbestos cases pending at September 30, 2018 , is presented below: Asbestos Cases Pending at September 30, 2018 Cases with specific dollar claims for damages: Claims up to $0.2 151 Claims above $0.2 to $5.0 4 Claims above $5.0 to $20.0 3 Total claims with specific dollar claims for damages (a) 158 Cases without a specific dollar claim for damages 172 Total asbestos cases pending 330 (a) Involve a total of 2,223 plaintiffs and 18,453 defendants
Schedule of Number of New Asbestos Claims Filed, Number of Pending Asbestos Claims Disposed, And Amount Paid in Settlements	Asbestos-related claims information for the three and nine months ended September 30, 2018 and 2017 is presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 New Claims Filed 13 18 46 46 Pending Claims Disposed Of 10 27 52 51 Total Amount Paid in Settlements $ 0.2 $ 0.3 $ 0.9 $ 0.9

Share-based Compensation (Table

Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule about share-based compensation expense	Information on share-based compensation expense is presented below: Three Months Ended September 30, Nine Months Ended September 30, Share-based Compensation Expense 2018 2017 2018 2017 Stock options $ 0.2 $ 0.2 $ 2.2 $ 1.9 Restricted stock 0.5 0.3 2.9 2.6 Restricted stock units issued to Directors 0.3 0.2 0.9 0.9 Performance shares 0.4 0.4 1.5 1.2 Equity-based long-term performance plan 0.1 — 0.3 — Total share-based compensation expense $ 1.5 $ 1.1 $ 7.8 $ 6.6

Comprehensive Income (Loss) (Ta

Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of T ax	Other comprehensive income (loss), net of tax, information is presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Foreign currency translation Balance at beginning of period $ — $ (1.0 ) $ 1.1 $ (3.6 ) Other comprehensive income (loss)—foreign currency translation gain (loss) (0.3 ) 1.4 (1.4 ) 4.0 Balance at end of period $ (0.3 ) $ 0.4 $ (0.3 ) $ 0.4 Cash flow hedges Balance at beginning of period $ 4.5 $ 21.8 $ 22.3 $ 39.9 Cumulative effect of adopting new hedging standard — — 0.8 — Other comprehensive income (loss): Gains (losses) arising in period (2.3 ) 7.3 (7.8 ) (8.9 ) Income tax expense (benefit) (b) — — — — Gains (losses) arising in period, net of tax (2.3 ) 7.3 (7.8 ) (8.9 ) Reclassification of losses (gains) to net income: Recorded in cost of products sold 0.5 (0.2 ) (12.6 ) (2.1 ) Income tax (expense) benefit (b) — — — — Net amount of reclassification of losses (gains) to net income, net of tax 0.5 (0.2 ) (12.6 ) (2.1 ) Total other comprehensive income (loss), net of tax (1.8 ) 7.1 (20.4 ) (11.0 ) Balance at end of period $ 2.7 $ 28.9 $ 2.7 $ 28.9 Pension and OPEB plans Balance at beginning of period $ (71.3 ) $ (148.7 ) $ (73.6 ) $ (125.0 ) Reclassification to net income: Prior service costs (credits) (a) (2.4 ) (13.6 ) (7.3 ) (40.6 ) Actuarial (gains) losses (a) 3.6 1.6 10.8 4.9 Subtotal 1.2 (12.0 ) 3.5 (35.7 ) Income tax (expense) benefit (b) — — — — Amount of reclassification to net income, net of tax 1.2 (12.0 ) 3.5 (35.7 ) Total other comprehensive income (loss), net of tax 1.2 (12.0 ) 3.5 (35.7 ) Balance at end of period $ (70.1 ) $ (160.7 ) $ (70.1 ) $ (160.7 ) (a) Included in pension and OPEB (income) expense (b)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings per share	Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net income (loss) attributable to AK Steel Holding Corporation $ 67.2 $ 22.3 $ 152.5 $ 183.9 Less: distributed earnings to common stockholders and holders of certain stock compensation awards — — — — Undistributed earnings $ 67.2 $ 22.3 $ 152.5 $ 183.9 Common stockholders earnings—basic and diluted: Distributed earnings to common stockholders $ — $ — $ — $ — Undistributed earnings to common stockholders 67.1 22.3 152.3 183.7 Common stockholders earnings—basic and diluted $ 67.1 $ 22.3 $ 152.3 $ 183.7 Common shares outstanding (weighted-average shares in millions): Common shares outstanding for basic earnings per share 314.9 314.3 314.8 314.2 Effect of exchangeable debt — 1.6 — 5.9 Effect of dilutive stock-based compensation 1.1 0.8 1.0 1.0 Common shares outstanding for diluted earnings per share 316.0 316.7 315.8 321.1 Basic earnings per share: Distributed earnings $ — $ — $ — $ — Undistributed earnings 0.21 0.07 0.48 0.58 Basic earnings per share $ 0.21 $ 0.07 $ 0.48 $ 0.58 Diluted earnings per share: Distributed earnings $ — $ — $ — $ — Undistributed earnings 0.21 0.07 0.48 0.57 Diluted earnings per share $ 0.21 $ 0.07 $ 0.48 $ 0.57 Potentially issuable common shares (in millions) excluded from earnings per share calculation due to anti-dilutive effect 2.5 1.5 2.3 1.1

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair value assets and liabilities measured on a recurring basis	Assets and liabilities measured at fair value on a recurring basis are presented below: September 30, 2018 December 31, 2017 Level 1 Level 2 Total Level 1 Level 2 Total Assets measured at fair value Cash and cash equivalents $ 47.3 $ — $ 47.3 $ 38.0 $ — $ 38.0 Other current assets: Foreign exchange contracts — 0.4 0.4 — 0.2 0.2 Commodity hedge contracts — 14.7 14.7 — 35.2 35.2 Other non-current assets: Foreign exchange contracts — 1.0 1.0 — 1.7 1.7 Commodity hedge contracts — 2.5 2.5 — 10.6 10.6 Assets measured at fair value $ 47.3 $ 18.6 $ 65.9 $ 38.0 $ 47.7 $ 85.7 Liabilities measured at fair value Accrued liabilities: Foreign exchange contracts $ — $ (0.5 ) $ (0.5 ) $ — $ (0.3 ) $ (0.3 ) Commodity hedge contracts — (3.8 ) (3.8 ) — (4.9 ) (4.9 ) Other non-current liabilities: Foreign exchange contracts — (0.3 ) (0.3 ) — — — Commodity hedge contracts — (1.5 ) (1.5 ) — (0.5 ) (0.5 ) Liabilities measured at fair value $ — $ (6.1 ) $ (6.1 ) $ — $ (5.7 ) $ (5.7 ) Liabilities measured at other than fair value Long-term debt, including current portions: Fair value $ — $ (2,108.7 ) $ (2,108.7 ) $ — $ (2,273.4 ) $ (2,273.4 ) Carrying amount — (2,034.9 ) (2,034.9 ) — (2,110.1 ) (2,110.1 )

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding commodity price swaps and options and forward foreign exchange contracts	Outstanding derivative contracts and the period over which we are hedging our exposure to the volatility in future cash flows are presented below: Derivative Contracts Settlement Dates September 30, December 31, Commodity contracts: Nickel (in lbs) — 500,000 Natural gas (in MMBTUs) October 2018 to October 2020 36,978,000 41,338,000 Zinc (in lbs) October 2018 to September 2020 42,300,000 50,350,000 Iron ore (in metric tons) October 2018 to May 2020 1,965,000 2,340,000 Electricity (in MWHs) October 2018 to June 2020 1,337,000 1,553,000 Foreign exchange contracts: Euros (in millions) October 2018 to December 2018 € 4.5 € 26.0 Canadian dollars (in millions) October 2018 to December 2021 C$ 133.1 C$ 148.1
Fair value of derivative instruments in the condensed consolidated balance sheets	The fair value of derivative instruments in the condensed consolidated balance sheets is presented below: Asset (liability) September 30, December 31, Derivatives designated as cash flow hedges: Other current assets: Foreign exchange contracts $ 0.2 $ 0.2 Commodity contracts 3.5 9.0 Other non-current assets: Foreign exchange contracts 1.0 1.7 Commodity contracts 0.2 2.3 Accrued liabilities: Foreign exchange contracts (0.5 ) (0.2 ) Commodity contracts (3.8 ) (4.6 ) Other non-current liabilities: Foreign exchange contracts (0.3 ) — Commodity contracts (1.5 ) (0.5 ) Derivatives not designated as cash flow hedges: Other current assets: Foreign exchange contracts 0.2 — Commodity contracts 11.2 26.2 Other non-current assets—commodity contracts 2.3 8.3 Accrued liabilities: Foreign exchange contracts — (0.1 ) Commodity contracts — (0.3 )
Gains (losses) on derivative instruments included in the condensed consolidated statements of operations	Gains (losses) on derivative instruments included in the condensed consolidated statements of operations and comprehensive income (loss) are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Gain (loss) Derivatives designated as cash flow hedges: Commodity contracts: Recognized in accumulated other comprehensive income that were included in the assessment of effectiveness $ (3.1 ) $ 7.3 $ (5.4 ) $ (8.9 ) Reclassified from accumulated other comprehensive income into cost of products sold 0.1 0.2 13.1 2.1 Foreign exchange contracts: Recognized in accumulated other comprehensive income that were included in the assessment of effectiveness 0.8 — (2.4 ) — Reclassified from accumulated other comprehensive income into cost of products sold (0.6 ) — (0.5 ) — Derivatives not designated as cash flow hedges: Commodity contracts—recognized in cost of products sold 4.5 3.9 (1.9 ) 11.0 Foreign exchange contracts—recognized in other income (expense) (0.1 ) (0.1 ) 0.3 (0.8 )
Amount of gains (losses) expected to be reclassified into earnings within the next twelve months	Gains (losses) before tax expected to be reclassified into cost of products sold within the next twelve months for our existing derivatives that qualify as cash flow hedges for hedge accounting are presented below: Hedge Gains (losses) Natural gas $ (0.1 ) Zinc (5.2 ) Electricity 2.7 Canadian dollars (1.3 )

Supplementary Cash Flow Infor_2

Supplementary Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2018
Supplemental Cash Flow Information [Abstract]
Schedule of cash flow, supplemental disclosures	Net cash paid (received) during the period for interest, net of capitalized interest, and income taxes are presented below: Nine Months Ended September 30, 2018 2017 Net cash paid (received) during the period for: Interest, net of capitalized interest $ 100.7 $ 101.1 Income taxes (5.7 ) (0.2 )
Schedule of non-cash investing and financing activities	Non-cash investing and financing activities are presented below: Nine Months Ended September 30, 2018 2017 Capital investments $ 25.6 $ 29.0 Issuance of restricted stock and restricted stock units 4.3 4.3

Supplementary Guarantor Infor_2

Supplementary Guarantor Information (Tables)	9 Months Ended
	Sep. 30, 2018
Supplemental Guarantor Information [Abstract]
Schedule of Condensed Comprehensive Income (Loss)	Condensed Consolidated Statements of Comprehensive Income (Loss) Three Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 1,602.0 $ 81.0 $ 179.0 $ (126.4 ) $ 1,735.6 Cost of products sold (exclusive of item shown separately below) — 1,401.3 54.8 145.7 (115.6 ) 1,486.2 Selling and administrative expenses 0.7 79.6 3.6 8.8 (13.1 ) 79.6 Depreciation — 43.8 2.0 9.2 — 55.0 Total operating costs 0.7 1,524.7 60.4 163.7 (128.7 ) 1,620.8 Operating profit (loss) (0.7 ) 77.3 20.6 15.3 2.3 114.8 Interest expense — 36.4 — 1.4 — 37.8 Pension and OPEB (income) expense — (10.0 ) — — — (10.0 ) Other (income) expense — 0.6 (4.3 ) (0.4 ) 4.8 0.7 Income (loss) before income taxes (0.7 ) 50.3 24.9 14.3 (2.5 ) 86.3 Income tax expense (benefit) — (3.9 ) 6.2 (0.3 ) (0.6 ) 1.4 Equity in net income (loss) of subsidiaries 67.9 13.7 — 0.5 (82.1 ) — Net income (loss) 67.2 67.9 18.7 15.1 (84.0 ) 84.9 Less: Net income attributable to noncontrolling interests — — — 17.7 — 17.7 Net income (loss) attributable to AK Steel Holding Corporation 67.2 67.9 18.7 (2.6 ) (84.0 ) 67.2 Other comprehensive income (loss) (0.9 ) (0.9 ) — (0.3 ) 1.2 (0.9 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 66.3 $ 67.0 $ 18.7 $ (2.9 ) $ (82.8 ) $ 66.3 Condensed Consolidated Statements of Comprehensive Income (Loss) Three Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 1,406.0 $ 71.3 $ 139.7 $ (122.7 ) $ 1,494.3 Cost of products sold (exclusive of item shown separately below) — 1,253.2 50.1 112.2 (113.7 ) 1,301.8 Selling and administrative expenses 0.9 69.2 3.1 6.1 (11.1 ) 68.2 Depreciation — 47.2 2.1 8.7 — 58.0 Total operating costs 0.9 1,369.6 55.3 127.0 (124.8 ) 1,428.0 Operating profit (loss) (0.9 ) 36.4 16.0 12.7 2.1 66.3 Interest expense — 37.1 — 0.4 — 37.5 Pension and OPEB (income) expense — (18.1 ) — — — (18.1 ) Other (income) expense — 13.1 (3.1 ) (2.2 ) — 7.8 Income (loss) before income taxes (0.9 ) 4.3 19.1 14.5 2.1 39.1 Income tax expense (benefit) — (6.3 ) 7.2 (1.9 ) 0.7 (0.3 ) Equity in net income (loss) of subsidiaries 23.2 12.6 — 0.2 (36.0 ) — Net income (loss) 22.3 23.2 11.9 16.6 (34.6 ) 39.4 Less: Net income attributable to noncontrolling interests — — — 17.1 — 17.1 Net income (loss) attributable to AK Steel Holding Corporation 22.3 23.2 11.9 (0.5 ) (34.6 ) 22.3 Other comprehensive income (loss) (3.5 ) (3.5 ) — 1.4 2.1 (3.5 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 18.8 $ 19.7 $ 11.9 $ 0.9 $ (32.5 ) $ 18.8 Condensed Consolidated Statements of Comprehensive Income (Loss) Nine Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 4,704.3 $ 242.5 $ 582.8 $ (388.5 ) $ 5,141.1 Cost of products sold (exclusive of item shown separately below) — 4,168.1 166.8 477.1 (349.4 ) 4,462.6 Selling and administrative expenses 2.8 233.2 11.0 26.5 (37.7 ) 235.8 Depreciation — 130.6 6.0 28.2 — 164.8 Total operating costs 2.8 4,531.9 183.8 531.8 (387.1 ) 4,863.2 Operating profit (loss) (2.8 ) 172.4 58.7 51.0 (1.4 ) 277.9 Interest expense — 109.3 — 4.0 — 113.3 Pension and OPEB expense (income) — (30.0 ) — — — (30.0 ) Other (income) expense — 6.4 (11.8 ) (2.8 ) 4.8 (3.4 ) Income (loss) before income taxes (2.8 ) 86.7 70.5 49.8 (6.2 ) 198.0 Income tax expense (benefit) — (21.8 ) 17.6 1.7 (1.5 ) (4.0 ) Equity in net income (loss) of subsidiaries 155.3 46.8 — 0.7 (202.8 ) — Net income (loss) 152.5 155.3 52.9 48.8 (207.5 ) 202.0 Less: Net income attributable to noncontrolling interests — — — 49.5 — 49.5 Net income (loss) attributable to AK Steel Holding Corporation 152.5 155.3 52.9 (0.7 ) (207.5 ) 152.5 Other comprehensive income (loss) (18.3 ) (18.3 ) — (1.4 ) 19.7 (18.3 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 134.2 $ 137.0 $ 52.9 $ (2.1 ) $ (187.8 ) $ 134.2 Condensed Consolidated Statements of Comprehensive Income (Loss) Nine Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net sales $ — $ 4,378.0 $ 217.7 $ 329.0 $ (339.8 ) $ 4,584.9 Cost of products sold (exclusive of item shown separately below) — 3,809.2 149.8 246.1 (306.4 ) 3,898.7 Selling and administrative expenses 3.3 210.3 9.5 16.4 (34.0 ) 205.5 Depreciation — 141.3 6.2 20.7 — 168.2 Total operating costs 3.3 4,160.8 165.5 283.2 (340.4 ) 4,272.4 Operating profit (loss) (3.3 ) 217.2 52.2 45.8 0.6 312.5 Interest expense — 114.0 — 1.1 — 115.1 Pension and OPEB expense (income) — (54.3 ) — — — (54.3 ) Other (income) expense — 32.3 (8.3 ) (4.8 ) — 19.2 Income (loss) before income taxes (3.3 ) 125.2 60.5 49.5 0.6 232.5 Income tax expense (benefit) — (22.4 ) 23.0 (0.6 ) 0.1 0.1 Equity in net income (loss) of subsidiaries 187.2 39.6 — 0.1 (226.9 ) — Net income (loss) 183.9 187.2 37.5 50.2 (226.4 ) 232.4 Less: Net income attributable to noncontrolling interests — — — 48.5 — 48.5 Net income (loss) attributable to AK Steel Holding Corporation 183.9 187.2 37.5 1.7 (226.4 ) 183.9 Other comprehensive income (loss) (42.7 ) (42.7 ) — 4.0 38.7 (42.7 ) Comprehensive income (loss) attributable to AK Steel Holding Corporation $ 141.2 $ 144.5 $ 37.5 $ 5.7 $ (187.7 ) $ 141.2
Schedule of Condensed Balance Sheet	Condensed Consolidated Balance Sheets September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company ASSETS Current assets: Cash and cash equivalents $ — $ 25.2 $ 2.2 $ 19.9 $ — $ 47.3 Accounts receivable, net — 562.6 38.5 112.4 (12.8 ) 700.7 Inventory — 1,221.0 60.0 75.9 (11.4 ) 1,345.5 Other current assets — 70.0 0.2 8.7 — 78.9 Total current assets — 1,878.8 100.9 216.9 (24.2 ) 2,172.4 Property, plant and equipment — 6,072.7 185.2 658.2 — 6,916.1 Accumulated depreciation — (4,749.1 ) (100.7 ) (157.2 ) — (5,007.0 ) Property, plant and equipment, net — 1,323.6 84.5 501.0 — 1,909.1 Investment in subsidiaries (3,056.2 ) 1,913.4 — 68.2 1,074.6 — Inter-company accounts 3,153.3 — 1,605.7 — (4,759.0 ) — Other non-current assets — 56.9 32.9 316.6 — 406.4 TOTAL ASSETS $ 97.1 $ 5,172.7 $ 1,824.0 $ 1,102.7 $ (3,708.6 ) $ 4,487.9 LIABILITIES AND EQUITY Current liabilities: Accounts payable $ — $ 699.2 $ 21.8 $ 56.7 $ (4.1 ) $ 773.6 Accrued liabilities — 219.8 7.6 29.9 — 257.3 Current portion of pension and other postretirement benefit obligations — 38.4 — 0.4 — 38.8 Total current liabilities — 957.4 29.4 87.0 (4.1 ) 1,069.7 Non-current liabilities: Long-term debt — 2,034.9 — — — 2,034.9 Pension and other postretirement benefit obligations — 794.3 — 3.2 — 797.5 Inter-company accounts — 4,326.8 — 511.2 (4,838.0 ) — Other non-current liabilities — 115.5 — 32.5 — 148.0 TOTAL LIABILITIES — 8,228.9 29.4 633.9 (4,842.1 ) 4,050.1 Equity: Total stockholders’ equity (deficit) 97.1 (3,056.2 ) 1,794.6 128.1 1,133.5 97.1 Noncontrolling interests — — — 340.7 — 340.7 TOTAL EQUITY 97.1 (3,056.2 ) 1,794.6 468.8 1,133.5 437.8 TOTAL LIABILITIES AND EQUITY $ 97.1 $ 5,172.7 $ 1,824.0 $ 1,102.7 $ (3,708.6 ) $ 4,487.9 Condensed Consolidated Balance Sheets December 31, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company ASSETS Current assets: Cash and cash equivalents $ — $ 14.5 $ 7.2 $ 16.3 $ — $ 38.0 Accounts receivable, net — 432.4 33.2 65.4 (13.2 ) 517.8 Inventory — 1,231.5 55.1 108.3 (9.9 ) 1,385.0 Other current assets — 124.7 0.2 5.4 — 130.3 Total current assets — 1,803.1 95.7 195.4 (23.1 ) 2,071.1 Property, plant and equipment — 6,004.0 181.5 646.3 — 6,831.8 Accumulated depreciation — (4,620.8 ) (94.8 ) (130.0 ) — (4,845.6 ) Property, plant and equipment, net — 1,383.2 86.7 516.3 — 1,986.2 Investment in subsidiaries (3,127.4 ) 1,844.9 — 67.5 1,215.0 — Inter-company accounts 3,082.8 — 1,523.1 — (4,605.9 ) — Other non-current assets — 66.3 33.0 318.2 — 417.5 TOTAL ASSETS $ (44.6 ) $ 5,097.5 $ 1,738.5 $ 1,097.4 $ (3,414.0 ) $ 4,474.8 LIABILITIES AND EQUITY Current liabilities: Accounts payable $ — $ 623.3 $ 17.9 $ 50.9 $ (1.7 ) $ 690.4 Accrued liabilities — 228.2 7.8 34.5 — 270.5 Current portion of pension and other postretirement benefit obligations — 39.7 — 0.4 — 40.1 Total current liabilities — 891.2 25.7 85.8 (1.7 ) 1,001.0 Non-current liabilities: Long-term debt — 2,110.1 — — — 2,110.1 Pension and other postretirement benefit obligations — 890.8 — 3.4 — 894.2 Inter-company accounts — 4,199.6 — 489.1 (4,688.7 ) — Other non-current liabilities — 133.2 1.0 34.7 — 168.9 TOTAL LIABILITIES — 8,224.9 26.7 613.0 (4,690.4 ) 4,174.2 Equity: Total stockholders’ equity (deficit) (44.6 ) (3,127.4 ) 1,711.8 139.2 1,276.4 (44.6 ) Noncontrolling interests — — — 345.2 — 345.2 TOTAL EQUITY (44.6 ) (3,127.4 ) 1,711.8 484.4 1,276.4 300.6 TOTAL LIABILITIES AND EQUITY $ (44.6 ) $ 5,097.5 $ 1,738.5 $ 1,097.4 $ (3,414.0 ) $ 4,474.8
Schedule of Condensed Cash Flow Statement	Condensed Consolidated Statements of Cash Flows Nine Months Ended September 30, 2018 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net cash flows from operating activities $ (2.1 ) $ 133.1 $ 47.6 $ 65.3 $ 6.0 $ 249.9 Cash flows from investing activities: Capital investments — (82.6 ) (3.7 ) (14.8 ) — (101.1 ) Other investing items, net — 0.7 — (0.5 ) — 0.2 Net cash flows from investing activities — (81.9 ) (3.7 ) (15.3 ) — (100.9 ) Cash flows from financing activities: Net borrowings (payments) under credit facility — (85.0 ) — — — (85.0 ) Inter-company activity 2.4 44.9 (48.9 ) 7.6 (6.0 ) — SunCoke Middletown distributions to noncontrolling interest owners — — — (54.0 ) — (54.0 ) Other financing items, net (0.3 ) (0.4 ) — — — (0.7 ) Net cash flows from financing activities 2.1 (40.5 ) (48.9 ) (46.4 ) (6.0 ) (139.7 ) Net increase (decrease) in cash and cash equivalents — 10.7 (5.0 ) 3.6 — 9.3 Cash and equivalents, beginning of period — 14.5 7.2 16.3 — 38.0 Cash and equivalents, end of period $ — $ 25.2 $ 2.2 $ 19.9 $ — $ 47.3 Condensed Consolidated Statements of Cash Flows Nine Months Ended September 30, 2017 AK Holding AK Steel Guarantor Subsidiaries of the Senior Notes Other Non-Guarantor Subsidiaries Eliminations Consolidated Company Net cash flows from operating activities $ (2.4 ) $ 55.9 $ 30.6 $ 64.8 $ 5.1 $ 154.0 Cash flows from investing activities: Capital investments — (78.5 ) (4.6 ) (5.6 ) — (88.7 ) Investment in acquired business, net of cash acquired — (360.9 ) — — — (360.9 ) Other investing items, net — 4.3 — (0.1 ) — 4.2 Net cash flows from investing activities — (435.1 ) (4.6 ) (5.7 ) — (445.4 ) Cash flows from financing activities: Net borrowings (payments) under credit facility — 415.0 — — — 415.0 Proceeds from issuance of long-term debt — 680.0 — — — 680.0 Redemption of long-term debt — (821.8 ) — — — (821.8 ) Debt issuance costs — (25.0 ) — — — (25.0 ) Inter-company activity 4.9 10.1 (24.5 ) 14.6 (5.1 ) — SunCoke Middletown distributions to noncontrolling interest owners — — — (58.2 ) — (58.2 ) Other financing items, net (2.5 ) — — — — (2.5 ) Net cash flows from financing activities 2.4 258.3 (24.5 ) (43.6 ) (5.1 ) 187.5 Net increase (decrease) in cash and cash equivalents — (120.9 ) 1.5 15.5 — (103.9 ) Cash and equivalents, beginning of period — 147.9 4.4 20.9 — 173.2 Cash and equivalents, end of period $ — $ 27.0 $ 5.9 $ 36.4 $ — $ 69.3

Summary of Significant Accoun_3

Summary of Significant Accounting Policies Accounting Change (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accounting Changes [Abstract]
Pension and OPEB (income) expense	$ (10)	$ (18.1)	$ (30)	$ (54.3)

Acquisition of Precision Part_2

Acquisition of Precision Partners (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Aug. 04, 2017
Business Acquisition [Line Items]
Business Acquisition, Transaction Costs	$ 4.7	$ 6.2
Precision Partners Holding Company [Member]
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Entity Number of Plants			8

Supplementary Financial State_3

Supplementary Financial Statement Information Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 1,735.6	$ 1,494.3	$ 5,141.1	$ 4,584.9
Non-US [Member]
Disaggregation of Revenue [Line Items]
Net sales	149.6	159.4	490.3	472.2
Carbon steel
Disaggregation of Revenue [Line Items]
Net sales	1,132.6	995.7	3,303.6	3,073
Stainless and electrical steel
Disaggregation of Revenue [Line Items]
Net sales	454.3	401.2	1,363.5	1,279.2
Tubular products, components and other
Disaggregation of Revenue [Line Items]
Net sales	148.7	97.4	474	232.7
Automotive
Disaggregation of Revenue [Line Items]
Net sales	1,036.7	948.8	3,264.5	2,986
Infrastructure and Manufacturing
Disaggregation of Revenue [Line Items]
Net sales	277.1	239.3	782.2	717.9
Distributors and Converters
Disaggregation of Revenue [Line Items]
Net sales	$ 421.8	$ 306.2	$ 1,094.4	$ 881

Supplementary Financial State_4

Supplementary Financial Statement Information Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished and semi-finished	$ 1,014.4	$ 996.8
Raw materials	331.1	388.2
Inventory	$ 1,345.5	$ 1,385

Supplementary Financial State_5

Supplementary Financial Statement Information LIFO (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold (exclusive of item shown separately below)		$ 1,486.2	$ 1,301.8	$ 4,462.6	$ 3,898.7
Income tax expense (benefit)		1.4	(0.3)	(4)	0.1
Net income		84.9	39.4	202	232.4
Net income attributable to AK Steel Holding Corporation		$ 67.2	$ 22.3	$ 152.5	$ 183.9
Basic		$ 0.21	$ 0.07	$ 0.48	$ 0.58
Diluted		$ 0.21	$ 0.07	$ 0.48	$ 0.57
Recorded in cost of products sold		$ 0.5	$ (0.2)	$ (12.6)	$ (2.1)
Comprehensive income		84	35.9	183.7	189.7
Comprehensive income attributable to AK Steel Holding Corporation		66.3	18.8	134.2	141.2
Inventory		1,345.5		1,345.5		$ 1,385
Other non-current assets		406.4		406.4		417.5
Other non-current liabilities		148		148		168.9
Accumulated deficit		(2,725.3)		(2,725.3)		(2,877)
Accumulated other comprehensive loss		(67.7)		(67.7)		(50.2)
Deferred income taxes				(6.3)	4.9
Changes in working capital				(11.1)	(156.2)
Other operating items, net				(30.6)	3.5
As If Under LIFO [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold (exclusive of item shown separately below)		1,499.7		4,504.8
Income tax expense (benefit)		(1.9)		(13.9)
Net income		74.7		169.7
Net income attributable to AK Steel Holding Corporation		$ 57		$ 120.2
Basic		$ 0.18		$ 0.38
Diluted		$ 0.18		$ 0.38
Comprehensive income		$ 73.8		$ 151.4
Comprehensive income attributable to AK Steel Holding Corporation		56.1		101.9
Inventory		1,067.8		1,067.8
Other non-current assets		480.1		480.1
Other non-current liabilities		146		146
Accumulated deficit		(2,939.2)		(2,939.2)
Deferred income taxes				(16.2)
Changes in working capital				29.4
Other operating items, net				(28.9)
Adjustment As If Under LIFO [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold (exclusive of item shown separately below)		(13.5)		(42.2)
Income tax expense (benefit)		3.3		9.9
Net income		10.2		32.3
Net income attributable to AK Steel Holding Corporation		$ 10.2		$ 32.3
Basic		$ 0.03		$ 0.10
Diluted		$ 0.03		$ 0.10
Comprehensive income		$ 10.2		$ 32.3
Comprehensive income attributable to AK Steel Holding Corporation		10.2		32.3
Inventory		277.7		277.7
Other non-current assets		(73.7)		(73.7)
Other non-current liabilities		2		2
Accumulated deficit		$ 213.9		213.9
Deferred income taxes				9.9
Changes in working capital				(40.5)
Other operating items, net				$ (1.7)
Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold (exclusive of item shown separately below)	[1]		1,348.4		4,005.7
Income tax expense (benefit)			(18.8)		(40.9)
Net income			11.3		166.4
Net income attributable to AK Steel Holding Corporation			$ (5.8)		$ 117.9
Basic			$ (0.02)		$ 0.37
Diluted			$ (0.02)		$ 0.37
Recorded in cost of products sold			$ (1.9)		$ (7.2)
Comprehensive income			6.1		118.6
Comprehensive income attributable to AK Steel Holding Corporation			(11)		70.1
Inventory						1,147.8
Other non-current assets						476
Other non-current liabilities						161.6
Accumulated deficit						(3,058.6)
Accumulated other comprehensive loss						(40)
Deferred income taxes					(36.1)
Changes in working capital					(44.1)
Other operating items, net					(1.6)
Restatement Adjustment [Member] | ChangeFromLIFOToAverageCostMethod [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of products sold (exclusive of item shown separately below)			(46.6)		(107)
Income tax expense (benefit)			18.5		41
Net income			28.1		66
Net income attributable to AK Steel Holding Corporation			$ 28.1		$ 66
Basic			$ 0.09		$ 0.21
Diluted			$ 0.09		$ 0.20
Recorded in cost of products sold			$ 1.7		$ 5.1
Comprehensive income			29.8		71.1
Comprehensive income attributable to AK Steel Holding Corporation			$ 29.8		71.1
Inventory						237.2
Other non-current assets						(58.5)
Other non-current liabilities						7.3
Accumulated deficit						181.6
Accumulated other comprehensive loss						$ (10.2)
Deferred income taxes					41
Changes in working capital					(112.1)
Other operating items, net					$ 5.1
[1]	(a) Cost of products sold as originally reported reflects the change in presentation of pension and OPEB (income) expense further described in Note 1

Supplementary Financial State_6

Supplementary Financial Statement Information Goodwill/Intangibles (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill balance			$ 253.8
Adjustment to acquisition purchase price			1.2
Goodwill balance	$ 255		255
Intangible Assets, Gross Amount	56.9		56.9		$ 56.9
Intangible Assets, Accumulated Amortization	(10.9)		(10.9)		(4)
Intangible Assets, Net Amount	46		46		52.9
Amortization of Intangible Assets	2.2	$ 1.8	6.9	$ 1.8
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	36.6		36.6		36.6
Intangible Assets, Accumulated Amortization	(6.1)		(6.1)		(2.2)
Intangible Assets, Net Amount	30.5		30.5		34.4
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	19.3		19.3		19.3
Intangible Assets, Accumulated Amortization	(3.8)		(3.8)		(1.4)
Intangible Assets, Net Amount	15.5		15.5		17.9
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	1		1		1
Intangible Assets, Accumulated Amortization	(1)		(1)		(0.4)
Intangible Assets, Net Amount	$ 0		$ 0		$ 0.6

Supplementary Financial State_7

Supplementary Financial Statement Information Affiliates (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Equity Method Investments [Line Items]
Revenue	$ 88.9	$ 73.2	$ 247.2	$ 222.5
Gross profit	24.5	20.5	69.2	69.6
Net income	6.4	3.4	15.7	18.8
Cost of Sales [Member]
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	$ 2.5	$ 1	$ 5.5	$ 6.6

Supplementary Financial State_8

Supplementary Financial Statement Information Facility Idling (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Ashland Works Hot End [Member]
Restructuring Cost and Reserve [Line Items]
Costs for Temporarily Idled Operations	$ 4.7	$ 5.1	$ 15.1	$ 15.9

Income Tax (Details)

Income Tax (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Income Tax Disclosure [Abstract]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 5.3

Long-term Debt and Other Fina_3

Long-term Debt and Other Financing Debt Notes (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized debt discount and issuance costs			$ (45.6)	$ (55.4)
Total long-term debt			2,034.9	2,110.1
Gain (Loss) on Repurchase of Debt Instrument	$ (8.4)	$ (21.5)
Senior Secured Notes Due July 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 380	$ 380
Debt Instrument, Interest Rate, Stated Percentage			7.50%	7.50%
Debt Instrument, Interest Rate, Effective Percentage			8.30%	8.30%
Exchangeable Senior Notes Due November 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 150	$ 150
Debt Instrument, Interest Rate, Stated Percentage			5.00%	5.00%
Debt Instrument, Interest Rate, Effective Percentage			10.80%	10.80%
Senior Notes Due October 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 406.2	$ 406.2
Debt Instrument, Interest Rate, Stated Percentage			7.625%	7.625%
Senior Notes Due October 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 280	$ 280
Debt Instrument, Interest Rate, Stated Percentage			6.375%	6.375%
Debt Instrument, Interest Rate, Effective Percentage			7.10%	7.10%
Senior Notes Due March 2027 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 400	$ 400
Debt Instrument, Interest Rate, Stated Percentage			7.00%	7.00%
Industrial Revenue Bonds [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 99.3	$ 99.3

Long-term Debt and Other Fina_4

Long-term Debt and Other Financing Credit Facility (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Line of Credit Facility [Line Items]
Net borrowings (payments) under credit facility	$ (85,000,000)	$ 415,000,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	1,350,000,000
Outstanding borrowings on revolving credit facility	365,000,000		$ 450,000,000
Line of Credit Facility, Current Borrowing Capacity	1,350,000,000
Letters of credit, outstanding	73,200,000
Line of credit facility, remaining borrowing capacity	$ 911,800,000

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits (Details) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Payment for Pension Benefits				$ 40.7	$ 38.1
Net periodic benefit cost (income) [Abstract]
Net periodic benefit (income) expense				(24.2)	(48.6)
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated pension plan contributions in current year		$ 49.9		49.9
Payment for Pension Benefits				40.7
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		40		40
Defined Benefit Plans, Estimated Future Employer Contributions, Year Two		80		80
Net periodic benefit cost (income) [Abstract]
Service cost		0.9	$ 0.7	2.4	2.1
Interest cost		23.7	27	71.2	81
Expected return on assets		(38.8)	(37.5)	(116.4)	(112.6)
Amortization of prior service cost (credit)		1	1.1	2.9	3.4
Amortization of (gain) loss		3.9	2.7	11.8	8.1
Net periodic benefit (income) expense		(9.3)	(6)	(28.1)	(18)
Other Postretirement Benefits [Member]
Net periodic benefit cost (income) [Abstract]
Service cost		1.1	1.2	3.4	3.5
Interest cost		3.9	4.4	11.7	13.1
Amortization of prior service cost (credit)		(3.4)	(14.7)	(10.2)	(44)
Amortization of (gain) loss		(0.3)	(1.1)	(1)	(3.2)
Net periodic benefit (income) expense		$ 1.3	$ (10.2)	$ 3.9	$ (30.6)
Subsequent Event [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Payment for Pension Benefits	$ 9.2
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement	$ 280
Number of employees affected by contract	5,400
Scenario, Forecast [Member] | Subsequent Event [Member] | Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	$ 3

Environmental and Legal Conti_3

Environmental and Legal Contingencies (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Accrued liabilities	$ 8	$ 8.5
Other non-current liabilities	$ 30.2	$ 35.4

Environmental and Legal Conti_4

Environmental and Legal Contingencies (Details 2) $ in Millions	Sep. 30, 2018USD ($)
Hamilton Plant [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	$ 0.7
Mansfield OH Works [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	1.1
Ashland coke plant [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	1.4
Ambridge Works [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	5.6
Middletown Works RCRA Site [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	12.8
Zanesville Works RCRA [Member]
Site Contingency [Line Items]
Site contingency accrual, undiscounted amount	$ 0.1

Environmental and Legal Conti_5

Environmental and Legal Contingencies (Details 3)		3 Months Ended		9 Months Ended
		Sep. 30, 2018USD ($)claims-lawsuits	Sep. 30, 2017USD ($)claims-lawsuits	Sep. 30, 2018USD ($)claims-lawsuitsdefendantsplaintiffs	Sep. 30, 2017USD ($)claims-lawsuits
Asbestos Claims With Specific Dollar Claim For Damages [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending	[1]	158		158
Claims with specific dollar claims for damages [Abstract]
Asbestos Lawsuits Pending With Dollars Number Of Plaintiffs | plaintiffs				2,223
Asbestos Lawsuits Pending With Dollars Number Of Defendants | defendants				18,453
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos Claims of Range 1 [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending		151		151
Claims with specific dollar claims for damages [Abstract]
Amount claimed per plaintiff, lower range | $				$ 0
Amount claimed per plaintiff, upper range | $				$ 200,000
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos Claims of Range 2 [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending		4		4
Claims with specific dollar claims for damages [Abstract]
Amount claimed per plaintiff, lower range | $				$ 200,000
Amount claimed per plaintiff, upper range | $				$ 5,000,000
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos Claims of Range 3 [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending		3		3
Claims with specific dollar claims for damages [Abstract]
Amount claimed per plaintiff, lower range | $				$ 5,000,000
Amount claimed per plaintiff, upper range | $				$ 20,000,000
Asbestos Claims Without Specific Dollar Claim For Damages [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending		172		172
Asbestos Issue [Member]
Information on pending asbestos cases [Line Items]
Number of asbestos cases pending		330		330
Claims with specific dollar claims for damages [Abstract]
New Claims Filed		13	18	46	46
Pending Claims Disposed Of		10	27	52	51
Total Amount Paid in Settlements | $		$ 200,000	$ 300,000	$ 900,000	$ 900,000
[1]	Involve a total of 2,223 plaintiffs and 18,453

Environmental and Legal Conti_6

Environmental and Legal Contingencies (Details 4) $ in Millions	1 Months Ended
	Mar. 31, 2014USD ($)
Antitrust Case [Member]
Loss Contingencies [Line Items]
Payments for Legal Settlements	$ 5.8

Share-based Compensation (Detai

Share-based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated share-based compensation expense	$ 9.4		$ 9.4
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	1.5	$ 1.1	7.8	$ 6.6
Stock Options [Member]
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	0.2	0.2	$ 2.2	1.9
Number of options granted (in shares)			842,000
Weighted-average grant-date fair value per share of options granted (dollars per share)			$ 3.51
Number of options exercised (in shares)			189,567
Restricted Stock [Member]
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	0.5	0.3	$ 2.9	2.6
Number of shares granted (in shares)			521,100
Weighted average grant date fair value, granted (dollars per share)			$ 6.56
Intrinsic value of shares vested/restrictions lapsed during the period			$ 3.2
Restricted Stock Units Issued to Directors [Member]
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	0.3	0.2	0.9	0.9
Performance shares [Member]
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	0.4	0.4	$ 1.5	1.2
Number of shares granted (in shares)			366,500
Weighted average grant date fair value, granted (dollars per share)			$ 8.05
Long-term Performance Plan [Member]
Share-based Compensation Expense [Abstract]
Share-based Compensation Expense	$ 0.1	$ 0	$ 0.3	$ 0
Share-based Compensation, Target Allocation of Equity Under Comprehensive Award (in hundredths)			30.00%
Share Based Compensation Arrangement By Share Based Payment Award, Performance Period			three-year

Comprehensive Income (Loss) (De

Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Foreign currency translation
Balance at beginning of period		$ 0	$ (1)	$ 1.1	$ (3.6)
Other comprehensive income (loss)—foreign currency translation gain (loss)		(0.3)	1.4	(1.4)	4
Balance at end of period		(0.3)	0.4	(0.3)	0.4
Cash flow hedges
Balance at beginning of period		4.5	21.8	22.3	39.9
Other comprehensive income (loss):
Gains (losses) arising in period		(2.3)	7.3	(7.8)	(8.9)
Income tax expense (benefit) (b)	[1]	0	0	0	0
Gains (losses) arising in period, net of tax		(2.3)	7.3	(7.8)	(8.9)
Reclassification of losses (gains) to net income:
Recorded in cost of products sold		0.5	(0.2)	(12.6)	(2.1)
Income tax (expense) benefit (b)	[1]	0	0	0	0
Net amount of reclassification of losses (gains) to net income, net of tax		0.5	(0.2)	(12.6)	(2.1)
Total other comprehensive income (loss), net of tax		(1.8)	7.1	(20.4)	(11)
Balance at end of period		2.7	28.9	2.7	28.9
Pension and OPEB plans
Balance at beginning of period		(71.3)	(148.7)	(73.6)	(125)
Reclassification to net income:
Prior service costs (credits) (a)		(2.4)	(13.6)	(7.3)	(40.6)
Actuarial (gains) losses (a)		3.6	1.6	10.8	4.9
Subtotal		1.2	(12)	3.5	(35.7)
Income tax (expense) benefit (b)	[1]	0	0	0	0
Amount of reclassification to net income, net of tax		1.2	(12)	3.5	(35.7)
Total other comprehensive income (loss), net of tax		1.2	(12)	3.5	(35.7)
Balance at end of period		(70.1)	(160.7)	(70.1)	(160.7)
Cost of Sales [Member]
Reclassification of losses (gains) to net income:
Recorded in cost of products sold		0.5	(0.2)	(12.6)	(2.1)
Pension and OPEB Expense (Income) [Member]
Reclassification to net income:
Prior service costs (credits) (a)	[2]	(2.4)	(13.6)	(7.3)	(40.6)
Actuarial (gains) losses (a)	[2]	$ 3.6	$ 1.6	$ 10.8	$ 4.9
Accumulated Other Comprehensive Income (Loss) [Member]
Cash flow hedges
Cumulative effect of adopting new hedging standard						$ 0	$ 0.8	$ 0	$ 0
[1]	Included in income tax expense (benefit)
[2]	Included in pension and OPEB (income) expense

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to AK Steel Holding Corporation	$ 67.2	$ 22.3	$ 152.5	$ 183.9
Less: distributed earnings to common stockholders and holders of certain stock compensation awards	0	0	0	0
Undistributed earnings	67.2	22.3	152.5	183.9
Common stockholders earnings—basic and diluted
Distributed earnings - basic and diluted	0	0	0	0
Undistributed earnings to common stockholders - basic and diluted	67.1	22.3	152.3	183.7
Common stockholders earnings—basic and diluted	67.1	22.3	152.3	183.7
Common stockholders earnings – diluted:
Distributed earnings to common stockholders - diluted	0	0	0	0
Undistributed earnings to common stockholders - diluted	67.1	22.3	152.3	183.7
Common stockholders earnings (loss) – diluted	$ 67.1	$ 22.3	$ 152.3	$ 183.7
Common shares outstanding (weighted-average shares in millions):
Common shares outstanding for basic earnings per share	314.9	314.3	314.8	314.2
Effect of exchangeable debt (in shares)	0	1.6	0	5.9
Effect of dilutive stock-based compensation (in shares)	1.1	0.8	1	1
Common shares outstanding for diluted earnings per share	316	316.7	315.8	321.1
Basic earnings per share:
Distributed earnings - basic (in dollars per share)	$ 0	$ 0	$ 0	$ 0
Undistributed earnings - basic (in dollars per share)	0.21	0.07	0.48	0.58
Basic earnings per share (in dollars per share)	0.21	0.07	0.48	0.58
Diluted earnings per share:
Distributed earnings - diluted (in dollars per share)	0	0	0	0
Undistributed earnings - diluted (in dollars per share)	0.21	0.07	0.48	0.57
Diluted earnings per share (in dollars per share)	$ 0.21	$ 0.07	$ 0.48	$ 0.57
Potentially issuable common shares (in millions) excluded from earnings per share calculation due to anti-dilutive effect (in shares)	2.5	1.5	2.3	1.1

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Variable Interest Entity [Line Items]
Income before income taxes	$ 86.3	$ 39.1	$ 198	$ 232.5
SunCoke Middletown [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable interest entity, ownership percentage (in hundredths)			0.00%
Income before income taxes	$ 17.8	$ 17.1	$ 49.8	$ 48.6
Vicksmetal Armco Associates [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable interest entity, ownership percentage (in hundredths)			50.00%

Fair Value Measurements (Detail

Fair Value Measurements (Details) $ in Millions	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Estimate of Fair Value, Fair Value Disclosure [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	$ (2,108.7)	$ (2,273.4)
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	(2,108.7)	(2,273.4)
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	(2,034.9)	(2,110.1)
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	0	0
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Debt Instrument, Fair Value Disclosure	(2,034.9)	(2,110.1)
Fair Value, Measurements, Recurring [Member]
Assets measured at fair value
Assets measured at fair value	65.9	85.7
Liabilities measured at fair value
Liabilities measured at fair value	(6.1)	(5.7)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Assets measured at fair value	47.3	38
Liabilities measured at fair value
Liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Assets measured at fair value	18.6	47.7
Liabilities measured at fair value
Liabilities measured at fair value	(6.1)	(5.7)
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member]
Assets measured at fair value
Cash and cash equivalents	47.3	38
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Cash and cash equivalents	47.3	38
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Cash and cash equivalents	$ 0	0
Measurement Input, Counterparty Credit Risk [Member] | Maximum [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Benchmark interest rates for asset contracts (in hundredths)	0.01
Benchmark interest rates for liability contracts (in hundredths)	0.03
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member]
Assets measured at fair value
Commodity hedge contracts - current	$ 0.4	0.2
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Commodity hedge contracts - current	0	0
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Commodity hedge contracts - current	0.4	0.2
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	1	1.7
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	0	0
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	1	1.7
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	(0.5)	(0.3)
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	0	0
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	(0.5)	(0.3)
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	(0.3)	0
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	0	0
Foreign Exchange Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	(0.3)	0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member]
Assets measured at fair value
Commodity hedge contracts - current	14.7	35.2
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Commodity hedge contracts - current	0	0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Commodity hedge contracts - current	14.7	35.2
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	2.5	10.6
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	0	0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Assets measured at fair value
Commodity hedge contracts - noncurrent	2.5	10.6
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	(3.8)	(4.9)
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	0	0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Accrued Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Commodity hedge contracts - current	(3.8)	(4.9)
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	(1.5)	(0.5)
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	0	0
Commodity Contract [Member] | Fair Value, Measurements, Recurring [Member] | Other Non-current Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities measured at fair value
Commodity hedge contracts - noncurrent	$ (1.5)	$ (0.5)

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Details) € in Millions, $ in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)MMBTUMWtlb	Sep. 30, 2018CAD ($)MMBTUMWtlb	Sep. 30, 2018EUR (€)MMBTUMWtlb	Dec. 31, 2017CAD ($)MMBTUMWtlb	Dec. 31, 2017EUR (€)MMBTUMWtlb
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 0
Commodity Contract [Member] | Nickel [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	0	0	0	500,000	500,000
Commodity Contract [Member] | Natural Gas [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MMBTU	36,978,000	36,978,000	36,978,000	41,338,000	41,338,000
Beginning Settlement Date	Oct. 1, 2018
Ending Settlement Date	Oct. 31, 2020
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (0.1)
Commodity Contract [Member] | Zinc [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	42,300,000	42,300,000	42,300,000	50,350,000	50,350,000
Beginning Settlement Date	Oct. 1, 2018
Ending Settlement Date	Sep. 30, 2020
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (5.2)
Commodity Contract [Member] | Iron Ore [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | t	1,965,000	1,965,000	1,965,000	2,340,000	2,340,000
Beginning Settlement Date	Oct. 1, 2018
Ending Settlement Date	May 31, 2020
Commodity Contract [Member] | Electricity [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MW	1,337,000	1,337,000	1,337,000	1,553,000	1,553,000
Beginning Settlement Date	Oct. 1, 2018
Ending Settlement Date	Jun. 20, 2020
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 2.7
Foreign Exchange Contract [Member] | Euro Member Countries, Euro
Derivative [Line Items]
Derivative, Notional Amount | €			€ 4.5		€ 26
Beginning Settlement Date	Oct. 1, 2018
Ending Settlement Date	Dec. 31, 2018
Foreign Exchange Contract [Member] | Canada, Dollars
Derivative [Line Items]
Derivative, Notional Amount		$ 133.1		$ 148.1
Beginning Settlement Date	Oct. 31, 2018
Ending Settlement Date	Dec. 31, 2021
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (1.3)

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities (Details 2) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	$ 3.5	$ 9
Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Non-current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Noncurrent	0.2	2.3
Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	(3.8)	(4.6)
Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Non-current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Noncurrent	(1.5)	(0.5)
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	0.2	0.2
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Non-current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Noncurrent	1	1.7
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	(0.5)	(0.2)
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Non-current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Noncurrent	(0.3)	0
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	11.2	26.2
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Other Non-current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Noncurrent	2.3	8.3
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	0	(0.3)
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	0.2	0
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	$ 0	$ (0.1)

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities (Details 3) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) arising in period	$ (2.3)	$ 7.3	$ (7.8)	$ (8.9)
Recorded in cost of products sold	(0.5)	0.2	12.6	2.1
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) arising in period	(3.1)	7.3	(5.4)	(8.9)
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) arising in period	0.8	0	(2.4)	0
Other Nonoperating Income (Expense) [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as cash flow hedges:	(0.1)	(0.1)	0.3	(0.8)
Cost of Products Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recorded in cost of products sold	(0.5)	0.2	12.6	2.1
Cost of Products Sold [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recorded in cost of products sold	0.1	0.2	13.1	2.1
Derivatives not designated as cash flow hedges:	4.5	3.9	(1.9)	11
Cost of Products Sold [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recorded in cost of products sold	(0.6)	0	(0.5)	0
Iron Ore [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Cash Received on Hedge	5.7	9.3	17.2	29.6
Iron Ore [Member] | Cost of Products Sold [Member] | Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives not designated as cash flow hedges:	$ 4.4	$ 4	$ (1.2)	$ 11.9

Supplementary Cash Flow Infor_3

Supplementary Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Supplemental cash flow, net cash paid (received) during the period for: [Abstract]
Interest, net of capitalized interest	$ 100.7	$ 101.1
Income taxes	(5.7)	(0.2)
Net Cash Provided by (Used in) Operating Activities	249.9	154
Cash and Cash Equivalents, at Carrying Value	47.3		$ 38
Supplemental cash flow, noncash investing and financing activities [Abstract]
Capital investments	25.6	29
Restricted Stock and Restricted Stock Units [Member]
Supplemental cash flow, noncash investing and financing activities [Abstract]
Issuance of restricted stock and restricted stock units	4.3	4.3
SunCoke Middletown [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Supplemental cash flow, net cash paid (received) during the period for: [Abstract]
Net Cash Provided by (Used in) Operating Activities	60.4	$ 59.2
Cash and Cash Equivalents, at Carrying Value	$ 5.2		$ 0.1

Union Contracts (Details)

Union Contracts (Details)	Sep. 30, 2018employees
Middletown Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	1,750
Ashland Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	240
Mountain State Carbon [Member]
Concentration Risk [Line Items]
Entity Number of Employees	220
Butler Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	1,180
Zanesville Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	100
Coshocton Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	310

Supplementary Guarantor Infor_3

Supplementary Guarantor Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 0	$ 360.9
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	$ 1,735.6	$ 1,494.3	5,141.1	4,584.9
Cost of products sold (exclusive of item shown separately below)	1,486.2	1,301.8	4,462.6	3,898.7
Selling and administrative expenses	79.6	68.2	235.8	205.5
Depreciation	55	58	164.8	168.2
Total operating costs	1,620.8	1,428	4,863.2	4,272.4
Operating profit (loss)	114.8	66.3	277.9	312.5
Interest expense	37.8	37.5	113.3	115.1
Pension and OPEB (income) expense	(10)	(18.1)	(30)	(54.3)
Other (income) expense	0.7	7.8	(3.4)	19.2
Income (loss) before income taxes	86.3	39.1	198	232.5
Income tax expense (benefit)	1.4	(0.3)	(4)	0.1
Equity in net income (loss) of subsidiaries	0	0	0	0
Net income	84.9	39.4	202	232.4
Less: Net income attributable to noncontrolling interests	17.7	17.1	49.5	48.5
Net income attributable to AK Steel Holding Corporation	67.2	22.3	152.5	183.9
Other comprehensive income (loss)	(0.9)	(3.5)	(18.3)	(42.7)
Comprehensive income attributable to AK Steel Holding Corporation	66.3	18.8	134.2	141.2
Current assets:
Cash and Cash Equivalents, at Carrying Value	47.3				$ 38
Accounts receivable, net	700.7				517.8
Inventory	1,345.5				1,385
Other current assets	78.9				130.3
Total current assets	2,172.4				2,071.1
Property, plant and equipment	6,916.1				6,831.8
Accumulated depreciation	(5,007)				(4,845.6)
Property, plant and equipment, net	1,909.1				1,986.2
Investment in subsidiaries	0				0
Inter-company accounts	0				0
Other non-current assets	406.4				417.5
TOTAL ASSETS	4,487.9				4,474.8
Current liabilities:
Accounts payable	773.6				690.4
Accrued liabilities	257.3				270.5
Current portion of pension and other postretirement benefit obligations	38.8				40.1
Total current liabilities	1,069.7				1,001
Non-current liabilities:
Long-term debt	2,034.9				2,110.1
Pension and other postretirement benefit obligations	797.5				894.2
Inter-company accounts	0				0
Other non-current liabilities	148				168.9
TOTAL LIABILITIES	4,050.1				4,174.2
Equity [Abstract]
Total stockholders' equity (deficit)	97.1				(44.6)
Noncontrolling interests	340.7				345.2
TOTAL EQUITY	437.8	306.7			300.6
TOTAL LIABILITIES AND EQUITY	4,487.9				4,474.8
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			249.9	154
Cash flows from investing activities:
Capital investments			(101.1)	(88.7)
Other investing items, net			0.2	4.2
Net cash flows from investing activities			(100.9)	(445.4)
Cash flows from financing activities:
Net borrowings (payments) under credit facility			(85)	415
Proceeds from issuance of long-term debt			0	680
Redemption of long-term debt			0	(821.8)
Debt issuance costs			0	(25)
Inter-company activity			0	0
SunCoke Middletown distributions to noncontrolling interest owners			(54)	(58.2)
Other financing items, net			(0.7)	(2.5)
Net cash flows from financing activities			(139.7)	187.5
Net increase (decrease) in cash and cash equivalents			9.3	(103.9)
Cash and cash equivalents, beginning of period			38	173.2
Cash and equivalents, end of period	47.3	69.3	38	173.2	38
AK Holding [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				0
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	0	0	0	0
Cost of products sold (exclusive of item shown separately below)	0	0	0	0
Selling and administrative expenses	0.7	0.9	2.8	3.3
Depreciation	0	0	0	0
Total operating costs	0.7	0.9	2.8	3.3
Operating profit (loss)	(0.7)	(0.9)	(2.8)	(3.3)
Interest expense	0	0	0	0
Pension and OPEB (income) expense	0	0	0	0
Other (income) expense	0	0	0	0
Income (loss) before income taxes	(0.7)	(0.9)	(2.8)	(3.3)
Income tax expense (benefit)	0	0	0	0
Equity in net income (loss) of subsidiaries	67.9	23.2	155.3	187.2
Net income	67.2	22.3	152.5	183.9
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to AK Steel Holding Corporation	67.2	22.3	152.5	183.9
Other comprehensive income (loss)	(0.9)	(3.5)	(18.3)	(42.7)
Comprehensive income attributable to AK Steel Holding Corporation	66.3	18.8	134.2	141.2
Current assets:
Cash and Cash Equivalents, at Carrying Value	0				0
Accounts receivable, net	0				0
Inventory	0				0
Other current assets	0				0
Total current assets	0				0
Property, plant and equipment	0				0
Accumulated depreciation	0				0
Property, plant and equipment, net	0				0
Investment in subsidiaries	(3,056.2)				(3,127.4)
Inter-company accounts	3,153.3				3,082.8
Other non-current assets	0				0
TOTAL ASSETS	97.1				(44.6)
Current liabilities:
Accounts payable	0				0
Accrued liabilities	0				0
Current portion of pension and other postretirement benefit obligations	0				0
Total current liabilities	0				0
Non-current liabilities:
Long-term debt	0				0
Pension and other postretirement benefit obligations	0				0
Inter-company accounts	0				0
Other non-current liabilities	0				0
TOTAL LIABILITIES	0				0
Equity [Abstract]
Total stockholders' equity (deficit)	97.1				(44.6)
Noncontrolling interests	0				0
TOTAL EQUITY	97.1				(44.6)
TOTAL LIABILITIES AND EQUITY	97.1				(44.6)
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			(2.1)	(2.4)
Cash flows from investing activities:
Capital investments			0	0
Other investing items, net			0	0
Net cash flows from investing activities			0	0
Cash flows from financing activities:
Net borrowings (payments) under credit facility			0	0
Proceeds from issuance of long-term debt				0
Redemption of long-term debt				0
Debt issuance costs				0
Inter-company activity			2.4	4.9
SunCoke Middletown distributions to noncontrolling interest owners			0	0
Other financing items, net			(0.3)	(2.5)
Net cash flows from financing activities			2.1	2.4
Net increase (decrease) in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and equivalents, end of period	0	0	0	0	0
AK Steel [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				360.9
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	1,602	1,406	4,704.3	4,378
Cost of products sold (exclusive of item shown separately below)	1,401.3	1,253.2	4,168.1	3,809.2
Selling and administrative expenses	79.6	69.2	233.2	210.3
Depreciation	43.8	47.2	130.6	141.3
Total operating costs	1,524.7	1,369.6	4,531.9	4,160.8
Operating profit (loss)	77.3	36.4	172.4	217.2
Interest expense	36.4	37.1	109.3	114
Pension and OPEB (income) expense	(10)	(18.1)	(30)	(54.3)
Other (income) expense	0.6	13.1	6.4	32.3
Income (loss) before income taxes	50.3	4.3	86.7	125.2
Income tax expense (benefit)	(3.9)	(6.3)	(21.8)	(22.4)
Equity in net income (loss) of subsidiaries	13.7	12.6	46.8	39.6
Net income	67.9	23.2	155.3	187.2
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to AK Steel Holding Corporation	67.9	23.2	155.3	187.2
Other comprehensive income (loss)	(0.9)	(3.5)	(18.3)	(42.7)
Comprehensive income attributable to AK Steel Holding Corporation	67	19.7	137	144.5
Current assets:
Cash and Cash Equivalents, at Carrying Value	25.2				14.5
Accounts receivable, net	562.6				432.4
Inventory	1,221				1,231.5
Other current assets	70				124.7
Total current assets	1,878.8				1,803.1
Property, plant and equipment	6,072.7				6,004
Accumulated depreciation	(4,749.1)				(4,620.8)
Property, plant and equipment, net	1,323.6				1,383.2
Investment in subsidiaries	1,913.4				1,844.9
Inter-company accounts	0				0
Other non-current assets	56.9				66.3
TOTAL ASSETS	5,172.7				5,097.5
Current liabilities:
Accounts payable	699.2				623.3
Accrued liabilities	219.8				228.2
Current portion of pension and other postretirement benefit obligations	38.4				39.7
Total current liabilities	957.4				891.2
Non-current liabilities:
Long-term debt	2,034.9				2,110.1
Pension and other postretirement benefit obligations	794.3				890.8
Inter-company accounts	4,326.8				4,199.6
Other non-current liabilities	115.5				133.2
TOTAL LIABILITIES	8,228.9				8,224.9
Equity [Abstract]
Total stockholders' equity (deficit)	(3,056.2)				(3,127.4)
Noncontrolling interests	0				0
TOTAL EQUITY	(3,056.2)				(3,127.4)
TOTAL LIABILITIES AND EQUITY	5,172.7				5,097.5
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			133.1	55.9
Cash flows from investing activities:
Capital investments			(82.6)	(78.5)
Other investing items, net			0.7	4.3
Net cash flows from investing activities			(81.9)	(435.1)
Cash flows from financing activities:
Net borrowings (payments) under credit facility			(85)	415
Proceeds from issuance of long-term debt				680
Redemption of long-term debt				(821.8)
Debt issuance costs				(25)
Inter-company activity			44.9	10.1
SunCoke Middletown distributions to noncontrolling interest owners			0	0
Other financing items, net			(0.4)	0
Net cash flows from financing activities			(40.5)	258.3
Net increase (decrease) in cash and cash equivalents			10.7	(120.9)
Cash and cash equivalents, beginning of period			14.5	147.9
Cash and equivalents, end of period	25.2	27	14.5	147.9	14.5
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				0
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	81	71.3	242.5	217.7
Cost of products sold (exclusive of item shown separately below)	54.8	50.1	166.8	149.8
Selling and administrative expenses	3.6	3.1	11	9.5
Depreciation	2	2.1	6	6.2
Total operating costs	60.4	55.3	183.8	165.5
Operating profit (loss)	20.6	16	58.7	52.2
Interest expense	0	0	0	0
Pension and OPEB (income) expense	0	0	0	0
Other (income) expense	(4.3)	(3.1)	(11.8)	(8.3)
Income (loss) before income taxes	24.9	19.1	70.5	60.5
Income tax expense (benefit)	6.2	7.2	17.6	23
Equity in net income (loss) of subsidiaries	0	0	0	0
Net income	18.7	11.9	52.9	37.5
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to AK Steel Holding Corporation	18.7	11.9	52.9	37.5
Other comprehensive income (loss)	0	0	0	0
Comprehensive income attributable to AK Steel Holding Corporation	18.7	11.9	52.9	37.5
Current assets:
Cash and Cash Equivalents, at Carrying Value	2.2				7.2
Accounts receivable, net	38.5				33.2
Inventory	60				55.1
Other current assets	0.2				0.2
Total current assets	100.9				95.7
Property, plant and equipment	185.2				181.5
Accumulated depreciation	(100.7)				(94.8)
Property, plant and equipment, net	84.5				86.7
Investment in subsidiaries	0				0
Inter-company accounts	1,605.7				1,523.1
Other non-current assets	32.9				33
TOTAL ASSETS	1,824				1,738.5
Current liabilities:
Accounts payable	21.8				17.9
Accrued liabilities	7.6				7.8
Current portion of pension and other postretirement benefit obligations	0				0
Total current liabilities	29.4				25.7
Non-current liabilities:
Long-term debt	0				0
Pension and other postretirement benefit obligations	0				0
Inter-company accounts	0				0
Other non-current liabilities	0				1
TOTAL LIABILITIES	29.4				26.7
Equity [Abstract]
Total stockholders' equity (deficit)	1,794.6				1,711.8
Noncontrolling interests	0				0
TOTAL EQUITY	1,794.6				1,711.8
TOTAL LIABILITIES AND EQUITY	1,824				1,738.5
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			47.6	30.6
Cash flows from investing activities:
Capital investments			(3.7)	(4.6)
Other investing items, net			0	0
Net cash flows from investing activities			(3.7)	(4.6)
Cash flows from financing activities:
Net borrowings (payments) under credit facility			0	0
Proceeds from issuance of long-term debt				0
Redemption of long-term debt				0
Debt issuance costs				0
Inter-company activity			(48.9)	(24.5)
SunCoke Middletown distributions to noncontrolling interest owners			0	0
Other financing items, net			0	0
Net cash flows from financing activities			(48.9)	(24.5)
Net increase (decrease) in cash and cash equivalents			(5)	1.5
Cash and cash equivalents, beginning of period			7.2	4.4
Cash and equivalents, end of period	2.2	5.9	7.2	4.4	7.2
Other Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				0
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	179	139.7	582.8	329
Cost of products sold (exclusive of item shown separately below)	145.7	112.2	477.1	246.1
Selling and administrative expenses	8.8	6.1	26.5	16.4
Depreciation	9.2	8.7	28.2	20.7
Total operating costs	163.7	127	531.8	283.2
Operating profit (loss)	15.3	12.7	51	45.8
Interest expense	1.4	0.4	4	1.1
Pension and OPEB (income) expense	0	0	0	0
Other (income) expense	(0.4)	(2.2)	(2.8)	(4.8)
Income (loss) before income taxes	14.3	14.5	49.8	49.5
Income tax expense (benefit)	(0.3)	(1.9)	1.7	(0.6)
Equity in net income (loss) of subsidiaries	0.5	0.2	0.7	0.1
Net income	15.1	16.6	48.8	50.2
Less: Net income attributable to noncontrolling interests	17.7	17.1	49.5	48.5
Net income attributable to AK Steel Holding Corporation	(2.6)	(0.5)	(0.7)	1.7
Other comprehensive income (loss)	(0.3)	1.4	(1.4)	4
Comprehensive income attributable to AK Steel Holding Corporation	(2.9)	0.9	(2.1)	5.7
Current assets:
Cash and Cash Equivalents, at Carrying Value	19.9				16.3
Accounts receivable, net	112.4				65.4
Inventory	75.9				108.3
Other current assets	8.7				5.4
Total current assets	216.9				195.4
Property, plant and equipment	658.2				646.3
Accumulated depreciation	(157.2)				(130)
Property, plant and equipment, net	501				516.3
Investment in subsidiaries	68.2				67.5
Inter-company accounts	0				0
Other non-current assets	316.6				318.2
TOTAL ASSETS	1,102.7				1,097.4
Current liabilities:
Accounts payable	56.7				50.9
Accrued liabilities	29.9				34.5
Current portion of pension and other postretirement benefit obligations	0.4				0.4
Total current liabilities	87				85.8
Non-current liabilities:
Long-term debt	0				0
Pension and other postretirement benefit obligations	3.2				3.4
Inter-company accounts	511.2				489.1
Other non-current liabilities	32.5				34.7
TOTAL LIABILITIES	633.9				613
Equity [Abstract]
Total stockholders' equity (deficit)	128.1				139.2
Noncontrolling interests	340.7				345.2
TOTAL EQUITY	468.8				484.4
TOTAL LIABILITIES AND EQUITY	1,102.7				1,097.4
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			65.3	64.8
Cash flows from investing activities:
Capital investments			(14.8)	(5.6)
Other investing items, net			(0.5)	(0.1)
Net cash flows from investing activities			(15.3)	(5.7)
Cash flows from financing activities:
Net borrowings (payments) under credit facility			0	0
Proceeds from issuance of long-term debt				0
Redemption of long-term debt				0
Debt issuance costs				0
Inter-company activity			7.6	14.6
SunCoke Middletown distributions to noncontrolling interest owners			(54)	(58.2)
Other financing items, net			0	0
Net cash flows from financing activities			(46.4)	(43.6)
Net increase (decrease) in cash and cash equivalents			3.6	15.5
Cash and cash equivalents, beginning of period			16.3	20.9
Cash and equivalents, end of period	19.9	36.4	16.3	20.9	16.3
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired				0
Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract]
Net sales	(126.4)	(122.7)	(388.5)	(339.8)
Cost of products sold (exclusive of item shown separately below)	(115.6)	(113.7)	(349.4)	(306.4)
Selling and administrative expenses	(13.1)	(11.1)	(37.7)	(34)
Depreciation	0	0	0	0
Total operating costs	(128.7)	(124.8)	(387.1)	(340.4)
Operating profit (loss)	2.3	2.1	(1.4)	0.6
Interest expense	0	0	0	0
Pension and OPEB (income) expense	0	0	0	0
Other (income) expense	4.8	0	4.8	0
Income (loss) before income taxes	(2.5)	2.1	(6.2)	0.6
Income tax expense (benefit)	(0.6)	0.7	(1.5)	0.1
Equity in net income (loss) of subsidiaries	(82.1)	(36)	(202.8)	(226.9)
Net income	(84)	(34.6)	(207.5)	(226.4)
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to AK Steel Holding Corporation	(84)	(34.6)	(207.5)	(226.4)
Other comprehensive income (loss)	1.2	2.1	19.7	38.7
Comprehensive income attributable to AK Steel Holding Corporation	(82.8)	(32.5)	(187.8)	(187.7)
Current assets:
Cash and Cash Equivalents, at Carrying Value	0				0
Accounts receivable, net	(12.8)				(13.2)
Inventory	(11.4)				(9.9)
Other current assets	0				0
Total current assets	(24.2)				(23.1)
Property, plant and equipment	0				0
Accumulated depreciation	0				0
Property, plant and equipment, net	0				0
Investment in subsidiaries	1,074.6				1,215
Inter-company accounts	(4,759)				(4,605.9)
Other non-current assets	0				0
TOTAL ASSETS	(3,708.6)				(3,414)
Current liabilities:
Accounts payable	(4.1)				(1.7)
Accrued liabilities	0				0
Current portion of pension and other postretirement benefit obligations	0				0
Total current liabilities	(4.1)				(1.7)
Non-current liabilities:
Long-term debt	0				0
Pension and other postretirement benefit obligations	0				0
Inter-company accounts	(4,838)				(4,688.7)
Other non-current liabilities	0				0
TOTAL LIABILITIES	(4,842.1)				(4,690.4)
Equity [Abstract]
Total stockholders' equity (deficit)	1,133.5				1,276.4
Noncontrolling interests	0				0
TOTAL EQUITY	1,133.5				1,276.4
TOTAL LIABILITIES AND EQUITY	(3,708.6)				(3,414)
Condensed Consolidated Statements of Cash Flows [Abstract]
Net cash flows from operating activities			6	5.1
Cash flows from investing activities:
Capital investments			0	0
Other investing items, net			0	0
Net cash flows from investing activities			0	0
Cash flows from financing activities:
Net borrowings (payments) under credit facility			0	0
Proceeds from issuance of long-term debt				0
Redemption of long-term debt				0
Debt issuance costs				0
Inter-company activity			(6)	(5.1)
SunCoke Middletown distributions to noncontrolling interest owners			0	0
Other financing items, net			0	0
Net cash flows from financing activities			(6)	(5.1)
Net increase (decrease) in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and equivalents, end of period	$ 0	$ 0	$ 0	$ 0	$ 0