Ak Steel Holding (AKS) 10-K 21 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 19, 2014	Jun. 30, 2013
Entity Information [Line Items]	'	'	'
Entity Registrant Name	'AK STEEL HOLDING CORP	'	'
Entity Central Index Key	'0000918160	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Accelerated Filer	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	136,684,433	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$408,782,178

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales	$1,464.80	$1,331.30	$1,404.50	$1,369.80	$1,423.10	$1,463.50	$1,538.40	$1,508.70	$5,570.40	$5,933.70	$6,468
Cost of products sold (exclusive of items shown separately below)	'	'	'	'	'	'	'	'	5,107.80	5,539.10	6,036.80
Selling and administrative expenses (exclusive of items shown separately below)	'	'	'	'	'	'	'	'	205.3	208.7	215.4
Depreciation	'	'	'	'	'	'	'	'	190.1	192	185
Pension and OPEB expense (income) (exclusive of corridor charges shown below)	'	'	'	'	'	'	'	'	-68.6	-35.3	-36
Pension corridor charges	'	'	'	'	157.3	'	'	'	0	157.3	268.1
Total operating costs	'	'	'	'	'	'	'	'	5,434.60	6,061.80	6,669.30
Operating profit (loss)	63	25.9	13.7	33.2	-176.9	-12	56.7	4.1	135.8	-128.1	-201.3
Interest expense	'	'	'	'	'	'	'	'	127.4	86.7	47.5
Other income (expense)	'	'	'	'	'	'	'	'	-1.4	6.2	-5.3
Income (loss) before income taxes	'	'	'	'	'	'	'	'	7	-208.6	-254.1
Income tax expense (benefit)	'	'	'	'	'	'	'	'	-10.4	790	-94
Net income (loss)	'	'	'	'	'	'	'	'	17.4	-998.6	-160.1
Less: Net income (loss) attributable to noncontrolling interests	'	'	'	'	'	'	'	'	64.2	28.7	-4.5
Net income (loss) attributable to AK Steel Holding Corporation	$35.20	($31.70)	($40.40)	($9.90)	($230.40)	($60.90)	($724.20)	($11.80)	($46.80)	($1,027.30)	($155.60)
Basic and diluted earnings per share:	'	'	'	'	'	'	'	'	'	'	'
Net income (loss) attributable to AK Steel Holding Corporation common stockholders (in dollars per share)	$0.26	($0.23)	($0.30)	($0.07)	($1.89)	($0.55)	($6.55)	($0.11)	($0.34)	($9.06)	($1.41)

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net income (loss)	$17.40		($998.60)		($160.10)
Other comprehensive income (loss), before tax:	'		'		'
Foreign currency translation gain (loss)	1.2		0.7		-0.7
Cash flow hedges:	'		'		'
Gains (losses) arising in period	3.5		6.3		-21
Reclassification of losses (gains) to net income (loss)	-25.2		36.3		4
Unrealized holding gains (losses) on securities:	'		'		'
Unrealized holding gains (losses) arising in period	0.2		0.9		-0.5
Pension and OPEB plans:	'		'		'
Prior service credit (cost) arising in period	-6.1		83.9		-20.6
Gains (losses) arising in period	422.3		-240.4		-319.4
Reclassification of prior service cost (credits) included in net income (loss)	-76.2	[1]	-71.1	[1]	-58.5	[1]
Reclassification of losses (gains) included in net income (loss)	25.3	[1]	181.8	[1]	272	[1]
Other comprehensive income (loss), before tax	345		-1.6		-144.7
Income tax expense (benefit) related to items of other comprehensive income (loss)	22.7		0		-54.8
Other comprehensive income (loss)	322.3		-1.6		-89.9
Comprehensive income (loss)	339.7		-1,000.20		-250
Less: Comprehensive income (loss) attributable to noncontrolling interests	64.2		28.7		-4.5
Comprehensive income (loss) attributable to AK Steel Holding Corporation	$275.50		($1,028.90)		($245.50)
[1]	Amounts are included in pension and OPEB expense (income) on the Consolidated Statements of Operations.

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$45.30	$227
Accounts receivable, net	525.2	473.9
Inventory, net	586.6	609.2
Deferred tax assets, current	69.6	73.2
Other current assets	46.5	59.4
Total current assets	1,273.20	1,442.70
Property, plant and equipment	5,871.90	5,943.90
Accumulated depreciation	-3,991.80	-3,931.60
Property, plant and equipment, net	1,880.10	2,012.30
Other non-current assets:	'	'
Investment in Magnetation LLC	187.8	150
Other non-current assets	264.6	298.1
TOTAL ASSETS	3,605.70	3,903.10
Current liabilities:	'	'
Accounts payable	601.8	538.3
Accrued liabilities	142.9	164.8
Current portion of long-term debt	0.8	0.7
Current portion of pension and other postretirement benefit obligations	85.9	108.6
Total current liabilities	831.4	812.4
Non-current liabilities:	'	'
Long-term debt	1,506.20	1,411.20
Pension and other postretirement benefit obligations	965.4	1,661.70
Other non-current liabilities	110	108.8
TOTAL LIABILITIES	3,413	3,994.10
Equity (deficit):	'	'
Common stock, authorized 200,000,000 shares of $.01 par value each; issued 149,691,388 and 149,094,571 shares in 2013 and 2012; outstanding 136,380,078 and 135,944,172 shares in 2013 and 2012	1.5	1.5
Additional paid-in capital	2,079.20	2,069.70
Treasury stock, common shares at cost, 13,311,310 and 13,150,399 shares in 2013 and 2012	-174	-173.3
Accumulated deficit	-2,451.10	-2,404.30
Accumulated other comprehensive income	323.4	1.1
Total stockholders' equity (deficit)	-221	-505.3
Noncontrolling interests	413.7	414.3
TOTAL EQUITY (DEFICIT)	192.7	-91
TOTAL LIABILITIES AND EQUITY (DEFICIT)	3,605.70	3,903.10
Variable Interest Entity, Primary Beneficiary [Member] | SunCoke Middletown [Member]	'	'
Current assets:	'	'
Cash and cash equivalents	14.2	0
Accounts receivable, net	0	1
Inventory, net	22.1	28.3
Property, plant and equipment	418.5	414.5
Accumulated depreciation	-29	-15
Other assets (liabilities), net	-0.7	-1.2
Current liabilities:	'	'
Accounts payable	13.3	15.4
Equity (deficit):	'	'
Noncontrolling interests	411.8	412.2
Variable Interest Entity, Primary Beneficiary [Member] | Other Variable Interest Entities [Member]	'	'
Current assets:	'	'
Cash and cash equivalents	1	1.2
Property, plant and equipment	11.5	11.4
Accumulated depreciation	-9.2	-8.9
Other assets (liabilities), net	0.6	0.6
Equity (deficit):	'	'
Noncontrolling interests	$1.90	$2.10

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS Parentheticals (USD $)	Dec. 31, 2013	Dec. 31, 2012
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares issued	149,691,388	149,094,571
Common stock, shares outstanding	136,380,078	135,944,172
Treasury stock, shares	13,311,310	13,150,399

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net income (loss)	$17.40	($998.60)	($160.10)
Adjustments to reconcile net income (loss) to cash flows from operating activities:	'	'	'
Depreciation	190.1	192	185
Amortization	19.1	17	15.5
Deferred income taxes	-7.3	771.2	-92.7
Income taxes of noncontrolling interests	0	17.6	-2.8
Contributions to pension trust	-181.1	-170.2	-170
Pension and OPEB expense (income)	-68.6	-35.3	-36
Pension corridor charges	0	157.3	268.1
Other operating items, net	9.4	-1.9	9
Change in assets and liabilities:	'	'	'
Other assets	-4.7	-4.2	-13.1
Pension obligations	-10	-6.7	-3.2
Postretirement benefit obligations	-63.4	-64.1	-75.5
Other liabilities	0.5	0.4	-17.4
Net cash flows from operating activities	-110.2	-270.8	-180.5
Cash flows from investing activities:	'	'	'
Capital investments	-63.6	-64.1	-296.1
Investments in acquired businesses	-50	-60.6	-125.4
Other investing items, net	15.1	6.1	1.3
Net cash flows from investing activities	-98.5	-118.6	-420.2
Cash flows from financing activities:	'	'	'
Net borrowings (repayments) under credit facility	90	-250	250
Proceeds from issuance of long-term debt	31.9	873.3	0
Redemption of long-term debt	-27.4	-74	-0.7
Proceeds from issuance of common stock	0	96.4	0
Debt issuance costs	-3.4	-22.3	-10.1
Common stock dividends paid	0	-11	-22
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	-64.8	-36.6	210.7
Other financing items, net	0.7	-1.4	-2
Net cash flows from financing activities	27	574.4	425.9
Net increase (decrease) in cash and cash equivalents	-181.7	185	-174.8
Cash and cash equivalents, beginning of year	227	42	216.8
Cash and cash equivalents, end of year	45.3	227	42
Middletown, Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]	'	'	'
Adjustments to reconcile net income (loss) to cash flows from operating activities:	'	'	'
Contributions to retirees VEBAs	-30.8	-31.7	-87.6
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]	'	'	'
Adjustments to reconcile net income (loss) to cash flows from operating activities:	'	'	'
Depreciation	176.1	178.4	183.6
Change in assets and liabilities:	'	'	'
Accounts receivable	-51.1	94.2	-81.3
Inventories	16.4	-182.8	55.1
Accounts payable and other current liabilities	48.7	-20.6	35.8
Cash flows from investing activities:	'	'	'
Capital investments	-60	-45.5	-101.1
SunCoke Middletown [Member]	'	'	'
Adjustments to reconcile net income (loss) to cash flows from operating activities:	'	'	'
Depreciation	14	13.6	1.4
Change in assets and liabilities:	'	'	'
Accounts receivable	1	0.3	0.5
Inventories	6.2	-4.5	-23.8
Accounts payable and other current liabilities	-2	-0.2	14
Cash flows from investing activities:	'	'	'
Capital investments	-3.6	-18.6	-195
Cash flows from financing activities:	'	'	'
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	($64.80)	($36.60)	$210.70

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]	Noncontrolling Interests [Member]
In Millions, unless otherwise specified
Balance at Dec. 31, 2010	$641.10	$1.20	$1,909.40	($170.10)	($1,188.40)	$92.60	($3.60)
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income (loss)	-160.1	'	'	'	-155.6	'	-4.5
Share-based compensation	14.9	'	14.9	'	'	'	'
Stock options exercised	0.2	'	0.2	'	'	'	'
Tax provision from share-based compensation	-2.3	'	-2.3	'	'	'	'
Purchase of treasury stock	-1.5	'	'	-1.5	'	'	'
Change in accumulated other comprehensive income	-89.9	'	'	'	'	-89.9	'
Common stock dividends	-22	'	'	'	-22	'	'
Net distributions to noncontrolling interests	-3.2	'	'	'	'	'	-3.2
Balance at Dec. 31, 2011	377.2	1.2	1,922.20	-171.6	-1,366	2.7	-11.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income (loss)	-998.6	'	'	'	-1,027.30	'	28.7
Issuance of common stock	96.4	0.3	96.1	'	'	'	'
Issuance of exchangeable debt	37.3	'	37.3	'	'	'	'
Share-based compensation	14.6	'	14.6	'	'	'	'
Tax provision from share-based compensation	-0.5	'	-0.5	'	'	'	'
Purchase of treasury stock	-1.7	'	'	-1.7	'	'	'
Change in accumulated other comprehensive income	-1.6	'	'	'	'	-1.6	'
Common stock dividends	-11	'	'	'	-11	'	'
Increase in noncontrolling interest as a result of SunCoke financing activities	416.1	'	'	'	'	'	416.1
Net distributions to noncontrolling interests	-36.8	'	'	'	'	'	-36.8
Income tax payable assumed by noncontrolling interests	17.6	'	'	'	'	'	17.6
Balance at Dec. 31, 2012	-91	1.5	2,069.70	-173.3	-2,404.30	1.1	414.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'	'
Net income (loss)	17.4	'	'	'	-46.8	'	64.2
Share-based compensation	9.5	'	9.5	'	'	'	'
Purchase of treasury stock	-0.7	'	'	-0.7	'	'	'
Change in accumulated other comprehensive income	322.3	'	'	'	'	322.3	'
Net distributions to noncontrolling interests	-64.8	'	'	'	'	'	-64.8
Balance at Dec. 31, 2013	$192.70	$1.50	$2,079.20	($174)	($2,451.10)	$323.40	$413.70

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of 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,” and together with AK Holding, the “Company”), all subsidiaries in which the Company has a controlling interest, and two variable interest entities for which the Company is the primary beneficiary.  The Company also operates European trading companies that buy and sell steel and steel products and other materials. The Company manages its operations on a consolidated, integrated basis in order to utilize the most appropriate equipment and facilities for the production of a product, regardless of product line, and concludes that it operates in a single business segment. All intercompany transactions and balances have been eliminated.
	Use of Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires the use of estimates and assumptions that affect the amounts reported.  These estimates are based on historical experience and information that is available to management about current events and actions the Company may take in the future.  Significant items subject to estimates and assumptions include the carrying value of long-lived assets, including goodwill; valuation allowances for receivables, inventories and deferred income tax assets; legal and environmental liabilities; workers compensation and asbestos liabilities; share-based compensation; investment in AFSG Holdings, Inc.; excess cost of operations; and assets and obligations related to employee benefit plans.  There can be no assurance that actual results will not differ from these estimates.
	Revenue Recognition: Revenue from sales of products is recognized at the time that title and the risks and rewards of ownership pass, which can be on the date of shipment or the date of receipt by the customer depending on when the terms of customers’ arrangements are met, the sales price is fixed or determinable, and collection is reasonably assured. Revenue is not recognized for sales taxes collected from customers; rather these taxes are recorded on a net basis in the Consolidated Statements of Operations.
	Cost of Products Sold: Cost of products sold consists primarily of raw materials, energy costs, supplies consumed in the manufacturing process, manufacturing labor, contract labor and direct overhead expense necessary to manufacture the finished steel product, as well as distribution and warehousing costs.  The Company’s share of the income (loss) of investments in associated companies accounted for under the equity method are included in costs of products sold since these operations are integrated with the Company’s overall steelmaking operations, except for its share of the income (loss) of Magnetation LLC that is included in other income (expense).
	Share-Based Compensation: Compensation costs related to all stock awards granted under the Company’s Stock Incentive Plan are charged against operations during their vesting period using the straight-line method.
	Legal Fees: Legal fees associated with litigation and similar proceedings that are not expected to provide a benefit in future periods are generally expensed as incurred. Legal fees associated with activities that are expected to provide a benefit in future periods, such as costs associated with the issuance of debt, are generally capitalized as incurred in the Consolidated Balance Sheets.
	Income Taxes: The Company records interest and penalties related to uncertain tax positions as a component of income tax expense. Deferred tax assets do not include certain amounts that arise from tax deductions related to share-based compensation in excess of compensation recognized for financial reporting when net operating loss carryforwards are created.  The Company uses tax law ordering for purposes of determining when excess tax benefits have been realized.
	Earnings per Share: Earnings per share is calculated using the “two-class” method. Under the “two-class” method, undistributed earnings are allocated to both common shares and participating securities. The sum of distributed earnings to common stockholders and undistributed earnings allocated to common stockholders is divided by the weighted-average number of common shares outstanding during the period. The restricted stock granted by AK Holding is entitled to dividends prior to vesting and meets the criteria of a participating security.
	Cash Equivalents: Cash equivalents include short-term, highly-liquid investments that are readily convertible to known amounts of cash and are of an original maturity of three months or less.
	Inventories: Inventories are valued at the lower of cost or market. The cost of the majority of inventories is measured on the last-in, first-out (LIFO) method. Other inventories are measured principally at average cost and consist mostly of foreign inventories and certain raw materials.
	Property, Plant and Equipment: Plant and equipment are depreciated under the straight-line method over their estimated lives.  Estimated lives are as follows: land improvements over 20 years, leaseholds over the life of the lease, buildings over 40 years and machinery and equipment over 2 to 20 years.  The estimated weighted-average life of the Company’s machinery and equipment is 19.1 years at the end of the current year.  Costs incurred to develop coal mines are capitalized. Depletion of coal reserves and mine development costs are computed using the units-of-production method utilizing only proven and probable reserves in the depletion base. The Company expenses costs associated with major maintenance activities at its operating facilities in the period in which they occur.
	The Company reviews the carrying value of long-lived assets to be held and used and long-lived assets to be disposed of when events and circumstances warrant such a review.  If the carrying value of a long-lived asset exceeds its fair value an impairment has occurred and a loss is recognized based on the amount by which the carrying value exceeds the fair value, less cost to dispose, for assets to be sold or abandoned.  Fair value is determined using quoted market prices, estimates based on prices of similar assets or anticipated cash flows discounted at a rate commensurate with risk.
	Investments: The Company has investments in associated companies that are accounted for under the equity method.  Each of these investments is subject to a review for impairment when circumstances indicate that a loss in value below its carrying amount is other than temporary.  No impairment was recorded in 2013, 2012 or 2011.
	The Company’s investment in AFSG Holdings, Inc., an indirect wholly-owned subsidiary of the Company, represents the carrying value of its discontinued insurance and finance leasing businesses, which have been largely liquidated.  The activities of the remaining operating companies are being “run off” and the companies are accounted for as a discontinued operation.  The Company is under no obligation to support the operations or liabilities of these companies.
	Goodwill: Goodwill relates primarily to the Company’s tubular business. Goodwill is reviewed for potential impairment at least annually on October 1 each year and whenever events or circumstances make it more likely than not that impairment may have occurred.  Considering operating results and the estimated fair value of the business, the most recent annual goodwill impairment test indicated that the fair value of the Company’s reporting unit with goodwill was in excess of its carrying value. No goodwill impairment was recorded as a result of the 2013, 2012 and 2011 annual reviews.
	Pension and Other Postretirement Benefits: The Company recognizes in operations, as of the measurement date, any unrecognized actuarial net gains or losses that exceed 10% of the larger of the projected benefit obligations or the plan assets, defined as the “corridor”.  Amounts inside the corridor are amortized over the plan participants’ life expectancy. The Company determines the expected return on assets using the fair value of plan assets.
	Concentrations of Credit Risk: The Company is primarily a producer of carbon, stainless and electrical steels and steel products, which are sold to a number of markets, including automotive, industrial machinery and equipment, construction, power distribution and appliances.  The following presents net sales by product line:
		2013			2012				2011
	Stainless and electrical	$	1,705.30		$	1,898.90			$	2,188.90
	Carbon	3,643.40			3,789.60				4,009.50
	Tubular	220.7			243.6				247.7
	Other	1			1.6				21.9
	Total	$	5,570.40		$	5,933.70			$	6,468.00
	The following sets forth the percentage of the Company’s net sales attributable to various markets:
		2013		2012			2011
	Automotive	51	%	45	%		36	%
	Infrastructure and Manufacturing	20	%	23	%		24	%
	Distributors and Converters	29	%	32	%		40	%
	The Company sells domestically to customers 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 totaled $708.0, $856.7 and $946.4 for 2013, 2012 and 2011, respectively. No customer accounted for more than 10% of net sales of the Company during 2013, 2012 and 2011.
	Approximately 41% and 43% of accounts receivable outstanding at December 31, 2013 and 2012, respectively, are due from businesses associated with the U.S. automotive industry.  Except in a few situations where the risk warrants it, collateral is not required on accounts receivable.  While the Company believes its recorded accounts receivable will be collected, in the event of default the Company would follow normal collection procedures. The Company maintains an allowance for doubtful accounts for the loss that would be incurred if a customer is unable to pay amounts due to the Company.  The Company determines this allowance based on various factors, including the customer’s financial condition and changes in customer payment patterns. The Company writes off accounts receivable against the allowance for doubtful accounts when it is remote that collection will occur.
	Union Contracts: At December 31, 2013, the Company employed approximately 6,400 employees, of which approximately 4,700 are represented by labor unions under various contracts that expire between 2014 and 2017.  An agreement with the United Steelworkers, Local 169, which represents approximately 280 employees at the Company’s Mansfield Works, is scheduled to expire on March 31, 2014. An agreement with the International Association of Machinists and Aerospace Workers, Local 1943, which represents approximately 1,650 employees at the Company’s Middletown Works, is scheduled to expire on September 15, 2014.
	Financial Instruments: Investments in debt securities are classified as held-to-maturity because the Company has the positive intent and ability to hold the securities to maturity.  Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity.  Investments in equity securities are classified as available-for-sale.  Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of tax, reported in other comprehensive income.  Realized gains and losses on sales of available-for-sale securities are computed based upon initial cost adjusted for any other than temporary declines in fair value.  The Company has no investments that are considered to be trading securities. Debt and equity securities are subject to a review for impairment when circumstances indicate that a loss in value is other than temporary.
	The Company is a party to derivative instruments that are designated and qualify as hedges for accounting purposes.  The Company may also enter into derivative instruments to which it does not apply hedge accounting treatment.  The Company’s objective in using these instruments is to protect its earnings and cash flows from fluctuations in the fair value of selected commodities and currencies.
	The Company’s income and cash flows may be affected by fluctuations in the price of certain commodities used in its production processes and in the selling price of certain commodity steel (hot roll carbon steel coils).  The Company has implemented raw material and energy surcharges for its spot market customers and some of its contract customers.  For certain commodities where such exposure exists, the Company may use cash-settled commodity price swaps, collars and purchase options, with a duration of up to three years, to hedge the price of a portion of its natural gas, iron ore, electricity, aluminum, zinc and nickel requirements or the selling price of hot roll carbon steel coils.  The Company may designate some of these instruments as cash flow hedges and the effective portion of the changes in their fair value and settlements are recorded in accumulated other comprehensive income.  Gains and losses are subsequently reclassified from accumulated other comprehensive income and recorded in cost of products sold or net sales in the same period as the earnings recognition of the associated underlying transaction.  Other instruments are marked to market and recorded in cost of products sold or net sales with the offset recorded as current assets or accrued liabilities.
	In addition, the Company is subject to risks associated with exchange rate fluctuations on monies received from its European subsidiaries and other customers invoiced in European currencies.  In order to mitigate this risk, the Company has entered into a series of agreements for the forward sale of euros at fixed dollar rates.  The forward contracts are entered into with durations of up to eighteen months.  A typical contract is used as a cash flow hedge for the period from when an order is taken to when a sale is recognized, at which time it converts into a fair value hedge of a euro-denominated receivable.  The Company does not classify these derivatives as hedges for accounting purposes and the hedges are marked to market on a quarterly basis with the expense or income recognized in other income (expense).
	The Company formally documents all relationships between hedging instruments and hedged items, as well as its risk management objectives and strategies for undertaking various hedge transactions.  In this documentation, the Company specifically identifies the asset, liability, firm commitment or forecasted transaction that has been designated as a hedged item, and states how the hedging instrument is expected to hedge the risks related to that item.  The Company formally measures effectiveness of its hedging relationships both at the hedge inception and on an ongoing basis.  The Company discontinues hedge accounting prospectively when it determines that the derivative is no longer effective in offsetting changes in the fair value or cash flows of a hedged item; when the derivative expires or is sold, terminated or exercised; when it is probable that the forecasted transaction will not occur; when a hedged firm commitment no longer meets the definition of a firm commitment; or when the Company determines that designation of the derivative as a hedge instrument is no longer appropriate.
	Asbestos and Environmental Accruals: The Company is, and has been for a number of years, in the process of remediating sites where hazardous material may have been released, including sites no longer owned by the Company.  In addition, a number of lawsuits alleging asbestos exposure have been filed and continue to be filed against the Company.  The Company has established accruals for estimated probable costs related to asbestos claim settlements and environmental investigation, monitoring and remediation.  If the accruals are not adequate to meet future claims, operating results and cash flows may be negatively affected.  The accruals do not consider the potential for insurance recoveries, for which the Company has partial insurance coverage for some future asbestos claims.  In addition, some existing insurance policies covering asbestos and environmental contingencies may serve to partially mitigate future covered expenditures.
	New Accounting Pronouncements: No new accounting pronouncement issued or effective during the 2013 fiscal year has had or is expected to have a material effect on the Company’s consolidated financial statements.

Supplementary_Financial_Statem

Supplementary Financial Statement Information	12 Months Ended
	Dec. 31, 2013
Supplementary Financial Statement Information [Abstract]	'
Supplementary Financial Statement Information	'
	Supplementary Financial Statement Information
	Research and Development Costs
	The Company conducts a broad range of research and development activities aimed at improving existing products and manufacturing processes and developing new products and processes.  Research and development costs, which are recorded as expense when incurred, totaled $13.2, $12.5 and $13.2 in 2013, 2012 and 2011, respectively.
	Allowance for Doubtful Accounts
	The following shows changes in the allowance for doubtful accounts for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	9.1		$	11.9		$	13.1
	Increase (decrease) in allowance	(0.4		)	(2.7		)	(1.1		)
	Receivables written off	(0.6		)	(0.1		)	(0.1		)
	Balance at end of year	$	8.1		$	9.1		$	11.9
	Inventory, net
	Inventories as of December 31, 2013 and 2012, consist of:
		2013			2012
	Finished and semi-finished	$	722.2		$	728.5
	Raw materials	260.9			315.7
	Total cost	983.1			1,044.20
	Adjustment to state inventories at LIFO value	(396.5		)	(435.0		)
	Inventory, net	$	586.6		$	609.2
	During 2013, 2012 and 2011, liquidation of LIFO layers generated income of $11.9, $0.9 and $109.9, respectively. The following shows changes in the LIFO reserve for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	435		$	524		$	514.2
	Change in reserve	(38.5		)	(89.0		)	9.8
	Balance at end of year	$	396.5		$	435		$	524
	Property, Plant and Equipment
	The Company’s property, plant and equipment balances as of December 31, 2013 and 2012 are as follows:
		2013			2012
	Land, land improvements and leaseholds	$	249.5		$	239.8
	Buildings	403.7			428.3
	Machinery and equipment	5,178.00			5,224.40
	Construction in progress	40.7			51.4
	Total	5,871.90			5,943.90
	Less accumulated depreciation	(3,991.8		)	(3,931.6		)
	Property, plant and equipment, net	$	1,880.10		$	2,012.30
	The amount of interest on capital projects capitalized in 2013, 2012 and 2011 was $2.7, $2.5 and $6.7, respectively. The Company had asset retirement obligations of $5.6 and $5.4 at December 31, 2013 and 2012, respectively.
	Other Non-current Assets
	Other non-current assets as of December 31, 2013 and 2012, consist of:
		2013			2012
	Investment in AFSG Holdings, Inc.	$	55.6		$	55.6
	Goodwill	37.1			37.1
	Deferred tax assets, non-current	76.6			88.2
	Other	95.3			117.2
	Other non-current assets	$	264.6		$	298.1

Investments_in_Equity_Investee

Investments in Equity Investees (Notes)	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Investments in Equity Investees	'
	Investments in Equity Investees
	The Company has investments in several businesses accounted for using the equity method of accounting. These investees are Combined Metals of Chicago, LLC (“Combined Metals”), Magnetation LLC (“Magnetation”) and Rockport Roll Shop LLC (“Rockport Roll Shop”), of which the Company has equity ownership of 40%, 49.9% and 50%, respectively. Cost of products sold includes the Company’s share of income from Combined Metals and Rockport Roll Shop of $8.1, $7.4 and $8.4 in 2013, 2012 and 2011, respectively. Included in other income (expense) was the Company’s share of income (loss) related to Magnetation of $(4.9) and $7.7 for 2013 and 2012, respectively.
	Summarized financial statement data for all investees is presented below. The Company is required to report this information for 2013 as a result of the comparative results of the investees to the Company. Although not previously required, prior period amounts have been disclosed for comparison.
			2013			2012			2011
	Revenue		$	293.9		$	297.9		$	237.5
	Gross profit		103.7			92.6			63.2
	Net income		20.1			40.8			20.2
			2013			2012
	Current assets		$	279.9		$	97.8
	Noncurrent assets		440.4			205.5
	Current liabilities		58.5			23.9
	Noncurrent liabilities		397.4			52.2
	The Company regularly transacts business with Combined Metals and Rockport Roll Shop.  The following relates to the Company’s transactions with these equity investees for the years indicated:
		2013			2012			2011
	Sales to equity investees	$	71.6		$	60.4		$	52.8
	Purchases from equity investees	12.5			11.8			12.4
	The following is the Company’s outstanding receivables and payables with the above equity investees as of the end of the year indicated:
		2013			2012
	Accounts receivable from equity investees	$	4		$	2.3
	Accounts payable to equity investees	0.9			1.1
	Notes receivable from equity investees	—			7.6
	Magnetation
	Magnetation utilizes advanced magnetic separation technology to recover iron ore from existing stockpiles of previously-mined material, such as tailings basins. Magnetation controls substantial volumes of these existing stockpiles, as well as other resources with significant amounts of iron content that could allow it to eventually recover iron ore from traditional mining operations. Traditional mining operations are not currently anticipated to be necessary for the foreseeable future, depending upon factors such as the recovery yield of Magnetation’s concentrate plants and future acquisitions of additional tailings basins and other iron-bearing resources. Through a pellet purchase agreement, AK Steel will have the right to purchase all of the pellets produced by Magnetations’s iron ore pelletizing plant when construction is completed, currently expected to occur in the fourth quarter of 2014 or sooner.
	AK Steel has committed to an investment of capital in Magnetation totaling $297.5. AK Steel has contributed a total of $197.5 for its interest in Magnetation through December 31, 2013 and the remaining $100.0 of contributions are anticipated to occur through late 2014 with the timing to be determined based on liquidity needs of Magnetation. AK Steel has no legal or contractual obligation to provide further financing to Magnetation beyond the amount mentioned above. The Company accounts for its investment under the equity method of accounting. As of December 31, 2013, the Company’s carrying cost of the investment exceeded its share of the underlying equity in net assets of Magnetation, recorded using historical carrying amounts, by $96.5. This difference is being amortized through equity in earnings and its amortization is included in the Company’s share of income (loss) amounts above.
	Subsequent to December 31, 2013, a wholly-owned subsidiary of the Company entered an operating lease to lease 675 rail cars to transport iron ore pellets from Magnetation’s Reynolds, Indiana pellet plant to the Company’s Middletown Works and Ashland Works blast furnaces. In connection with the transaction, AK Steel executed a guarantee of its subsidiary’s obligations under the lease agreement. The Company will make annual lease payments of $4.3 under the fifteen-year lease agreement.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company and its subsidiaries file a consolidated federal income tax return.  This return includes all domestic companies owned 80% or more by the Company and the proportionate share of the Company’s interest in equity method investments.  State tax returns are filed on a consolidated, combined or separate basis depending on the applicable laws relating to the Company and its domestic subsidiaries.
	Components of income (loss) before income taxes are as follows:
		2013			2012			2011
	United States	$	(61.1	)	$	(261.2	)	$	(252.5	)
	Foreign	3.9			6.3			5.7
	Noncontrolling interests	64.2			46.3			(7.3		)
	Income (loss) before income taxes	$	7		$	(208.6	)	$	(254.1	)
	Significant components of the Company’s deferred tax assets and liabilities at December 31, 2013 and 2012 are as follows:
		2013			2012
	Deferred tax assets:
	Net operating loss and tax credit carryforwards	$	663.5		$	625
	Postretirement benefits	185			231.6
	Pension benefits	216.6			374
	Inventories	118.8			116.7
	Other assets	96.3			94.4
	Valuation allowance	(764.1		)	(873.1		)
	Total deferred tax assets	516.1			568.6
	Deferred tax liabilities:
	Depreciable assets	(333.1		)	(357.7		)
	Other liabilities	(36.8		)	(49.5		)
	Total deferred tax liabilities	(369.9		)	(407.2		)
	Net deferred tax assets	$	146.2		$	161.4
	The Company regularly evaluates the need for a valuation allowance for deferred tax assets by assessing whether it is more likely than not that it will realize the deferred tax assets in the future. A valuation allowance assessment is performed each reporting period, with any additions or adjustments reflected in earnings in the period of assessment. In assessing the need for a valuation allowance, the Company has considered both positive and negative evidence related to the likelihood of realization of the deferred tax assets for each jurisdiction. The Company considered negative evidence, including a cumulative loss in recent periods and the effects of increased competition in the markets served by the Company, on its ability to generate future taxable income. That included increased competition in North America as a result of new or expanded production capacity added by domestic competitors of the Company, as well as increased imports from foreign producers. In general, the existence of cumulative losses in recent periods was deemed to be significant objective negative evidence. Other factors considered by the Company include:
	•	The Company’s historical operating results, including the lack of prior expired federal loss carryforwards during the Company’s prior business cycles
	•	Lengthy loss carryforward periods
	◦	Federal net operating loss carryforwards do not begin to expire until 2023 and substantial amounts of those loss carryforwards had most of their carryforward period remaining before expiration
	◦	Temporary differences other than loss carryforwards will have a 20-year carryforward period for federal purposes from the year of deduction on the tax return if the Company is in a loss carryforward position at that time; otherwise they will reduce taxable earnings in the year of deduction
	•	Timing of future reversals of existing taxable temporary differences
	•	An uncertain U.S. economic environment with uneven recovery across industry markets
	•	Greater widespread uncertainty and deterioration in the economies of Western Europe
	•	The effects of a slowdown in the Chinese economy, including increases in exports of some categories of Chinese steel to the United States
	As of December 31, 2013 and 2012, the Company concluded that the negative evidence outweighed the positive evidence and recorded a valuation allowance for a significant portion of its deferred tax assets. In accordance with applicable accounting standards, the Company is unable to use future income projections to support the realization of the deferred tax assets as a consequence of the above conclusions. However, in determining the appropriate amount of the valuation allowance, the Company considered the timing of future reversal of its taxable temporary differences and available tax strategies that, if implemented, would result in realization of deferred tax assets. The Company identified the potential change from the LIFO inventory accounting method as such a tax-planning strategy. The Company believes that this strategy is prudent and feasible in order to prevent certain federal and state tax loss carryforwards from expiring unused. In addition, the Company believes that the future reversal of its deferred tax liabilities serves as a source of taxable income supporting realization of a portion of its federal and state deferred tax assets. This accounting treatment has no effect on the ability of the Company to use the loss carryforwards and tax credits in the future to reduce cash tax payments. Federal net operating loss carryforwards do not begin to expire until 2023 and substantial amounts of those loss carryforwards have most of their 20-year life remaining before expiration.
	The following reflects changes in the valuation allowance for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	873.1		$	22.3		$	21.6
	Change in valuation allowance:
	Included in income tax expense (benefit)	21.9			865.5			0.7
	Change in deferred assets related to other comprehensive income	(130.9		)	—			—
	Included in stockholders’ equity related to issuance of exchangeable debt	—			(14.7		)	—
	Balance at end of year	$	764.1		$	873.1		$	22.3
	The Company recorded a non-cash charge of $735.2 in the year ended December 31, 2012, for an adjustment of the valuation allowance because of the change in judgment about the realizability of the deferred tax assets during that year.
	At December 31, 2013, the Company had $1,826.3 in federal regular net operating loss carryforwards and $2,207.0 in federal alternative minimum tax (“AMT”) net operating loss carryforwards, which will expire between 2023 and 2033.  At December 31, 2013, the Company had unused AMT credit carryforwards of $20.1 and research and development (“R&D”) credit carryforwards of $1.2. The loss and credit carryforwards may be used to offset future regular and AMT income tax liabilities.  The unused AMT credits can be carried forward indefinitely and the R&D credits don’t begin to expire until 2027. At December 31, 2013, the Company had $73.3 in deferred tax assets before consideration of valuation allowances for state net operating loss carryforwards and tax credit carryforwards, which will expire between 2014 and 2033.
	As of December 31, 2013, there were $21.0 of unrecognized deferred tax assets that arose from tax deductions related to share-based compensation in excess of compensation recognized for financial reporting when net operating loss carryforwards were created.  Additional paid-in capital will be increased when such deferred tax assets are ultimately realized.
	The Company has undistributed earnings of foreign subsidiaries of approximately $26.9 at December 31, 2013. Deferred taxes have not been provided on these earnings since the balance is considered to be permanently invested in the Company’s foreign subsidiaries.  If such undistributed earnings were repatriated, it is estimated that the additional tax expense to be provided would be approximately $9.4 before consideration of the effects on the valuation allowance.
	Significant components of income tax expense (benefit) are as follows:
		2013			2012			2011
	Current:
	Federal	$	(3.4	)	$	—		$	—
	State	0.2			1			(2.1		)
	Foreign	1.9			1.9			1.8
	Noncontrolling interests	—			17.6			(2.8		)
	Deferred:
	Federal	14			31.5			(84.9		)
	State	1.2			2.8			(6.0		)
	Amount allocated to other comprehensive income	(22.7		)	—			—
	Change in valuation allowance on beginning-of-the-year deferred tax assets	(1.6		)	735.2			—
	Income tax expense (benefit)	$	(10.4	)	$	790		$	(94.0	)
	In the first quarter of 2013, SunCoke Energy, Inc. (“SunCoke”) completed an initial public offering of an affiliate, SunCoke Energy Partners, L.P., a master limited partnership. As a result of a change in the legal structure of the SunCoke entities that own Middletown Coke Company, LLC (“SunCoke Middletown”) made in connection with the offering, income taxes are no longer allocated to net income attributable to SunCoke Middletown beginning in the first quarter of 2013. Thus, effective January 1, 2013, the Company’s income tax expense no longer includes the effect of that allocation. Neither the former tax allocation nor the January 1, 2013 change eliminating that allocation had any effect on the net income (loss) attributable to AK Steel Holding Corporation in any period.
	The reconciliation of income tax on income (loss) before income taxes computed at the U.S. federal statutory tax rates to actual income tax expense (benefit) is as follows:
		2013			2012			2011
	Income tax expense (benefit) at U.S. federal statutory rate	$	2.4		$	(73.0	)	$	(89.0	)
	Income tax expense on noncontrolling interest earnings not taxable to the Company	(22.5		)	—			—
State and foreign tax expense, net of federal tax	1.7			(4.8		)	(9.9		)
Increase in deferred tax asset valuation allowance	21.9			865.5			—
Amount allocated to other comprehensive income	(22.7		)	—			—
Effect of state law changes on deferred tax assets, net of federal tax	—			—			2
Change in accrual for uncertain tax positions	(1.7		)	—			—
Stock compensation in excess of tax deduction	3.1			—			—
Expiration of charitable contribution carryforwards	2.5			—			—
Other permanent differences	4.9			2.3			2.9
Income tax expense (benefit)	$	(10.4	)	$	790		$	(94.0	)
Federal, state and local tax returns of the Company and its subsidiaries are routinely subjected to examination by various taxing authorities.  Federal returns for periods beginning in 2010 are open for examination, while certain state and local returns are open for examination for periods beginning in 2007. However, taxing authorities have the ability to adjust net operating loss carryforwards from years prior to these periods.  The Company has not recognized certain tax benefits because of the uncertainty of realizing the entire value of the tax position taken on income tax returns upon review by the taxing authorities. The Company has established appropriate income tax accruals, and believes that the outcomes of future federal examinations as well as ongoing and future state and local examinations will not have a material adverse impact on the Company’s financial position, results of operations or cash flows. Unrecognized tax benefits will be included as an adjustment to income tax expense upon the expiration of the statutes of limitations or upon resolution with the taxing authorities. The Company has no tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change within twelve months of December 31, 2013.
A reconciliation of the change in federal and state unrecognized tax benefits for 2013, 2012 and 2011 is presented below:
	2013			2012			2011
Balance at beginning of year	$	54		$	49.2		$	50.3
Increases (decreases) for prior year tax positions	(0.8		)	1.6			1.3
Increases (decreases) for current year tax positions	0.9			3.7			(0.7		)
Increases (decreases) related to settlements	—			—			(0.2		)
(Decreases) related to statute lapse	(0.3		)	(0.5		)	(1.5		)
Balance at end of year	$	53.8		$	54		$	49.2
Included in the balance of unrecognized tax benefits at December 31, 2013 and 2012, are $42.6 and $42.4, respectively, of tax benefits that, if recognized, would affect the effective tax rate. Also included in the balance of unrecognized tax benefits at December 31, 2013 and 2012, are $11.2 and $11.6, respectively, of tax benefits that, if recognized, would result in adjustments to other tax accounts, primarily deferred taxes. Accrued interest and penalties were $0.7 and $4.0 at December 31, 2013 and 2012, respectively.

Longterm_Debt_and_Other_Financ

Long-term Debt and Other Financing	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Long-term Debt and Other Financing	'
	Long-term Debt and Other Financing
	At December 31, 2013 and 2012, the Company’s debt balances, including current portions, were as follows:
		2013			2012
	Credit Facility	$	90		$	—
	8.75% Senior Secured Notes due December 2018	380			350
	5.00% Exchangeable Senior Notes due November 2019 (effective rate of 10.8%)	150			150
	7.625% Senior Notes due May 2020	529.8			550
	8.375% Senior Notes due April 2022	290.2			300
	Industrial Revenue Bonds due 2014 through 2030	100.1			100.9
	Unamortized debt discount/premium, net	(33.1		)	(39.0		)
	Total debt	1,507.00			1,411.90
	Less:
	Current portion of long-term debt	0.8			0.7
	Total long-term debt	$	1,506.20		$	1,411.20
	During the period, the Company was in compliance with all the terms and conditions of its debt agreements. At December 31, 2013, the maturities of long-term debt, including the amount outstanding on the Credit Facility, for the next five years are as follows:
	Year		Debt Maturities
	2014		$	0.8
	2015		—
	2016		90
	2017		—
	2018		380
	Credit Facility
	AK Steel has a $1.1 billion asset-backed revolving credit facility (“Credit Facility”) with a group of lenders that currently is scheduled to expire in April 2016. The Credit Facility contains common restrictions, including limitations on, among other things, distributions and dividends, acquisitions and investments, indebtedness, liens and affiliate transactions. Availability is calculated as the lesser of the Credit Facility commitments or the Company’s eligible collateral after advance rates, less outstanding revolver borrowings and letters of credit. The Company’s obligation under its Credit Facility is secured by its inventory and accounts receivable and availability under the Credit Facility fluctuates monthly based on the varying levels of eligible collateral. In addition, the Credit Facility requires maintenance of a minimum fixed charge coverage ratio of one to one if availability under the Credit Facility is less than $137.5. Current availability under the Credit Facility significantly exceeds $137.5. AK Holding is the sole guarantor of the Credit Facility. The Company does not expect any of these restrictions to affect or limit its ability to conduct its business in the ordinary course. At December 31, 2013, the Company’s eligible collateral, after application of applicable advance rates, was $972.1. As of December 31, 2013, there were borrowings of $90.0. Availability as of December 31, 2013 was further reduced by $67.1 attributable to outstanding letters of credit, resulting in remaining availability of $815.0. The weighted-average interest rate on the outstanding borrowings at December 31, 2013 was 2.2%.
	Senior Secured Notes
	In November 2012, the Company issued $350.0 aggregate principal amount of 8.75% Senior Secured Notes due December 2018 and generated net proceeds of $341.1 after underwriting discounts and other expenses. In June 2013, AK Steel issued $30.0 of aggregate principal amount (the “add-on notes”) of its 8.75% Senior Secured Notes due 2018 at an issue price of 106.50%, as an add-on to its outstanding $350.0 aggregate principal amount of such notes (collectively, the “Secured Notes”). The add-on notes will be treated as a single series with the existing notes and have the same terms as the existing notes. Net proceeds from the issuance of the add-on notes were $30.9. Substantially all property, plant and equipment of AK Steel is pledged as collateral for the Secured Notes. AK Holding fully and unconditionally, jointly and severally, guarantees the payment of interest, principal and premium, if any, on the Secured Notes. The book value of such collateral as of December 31, 2013 was approximately $1.4 billion. The indenture governing the Secured Notes includes covenants with customary restrictions on (a) the incurrence of additional debt by certain AK Steel subsidiaries, (b) the incurrence of liens by AK Steel and AK Holding’s other subsidiaries, (c) the amount of sale/leaseback transactions, (d) the use of proceeds from the sale of collateral, and (e) the ability of AK Steel and AK Holding to merge or consolidate with other entities or to sell, lease or transfer all or substantially all of the assets of AK Steel and AK Holding to another entity. The Secured Notes also contain customary events of default. Prior to December 1, 2015, AK Steel may redeem the Secured Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption. Subsequent to that date, they are redeemable at 104.375% until December 1, 2016, 102.188% thereafter until December 1, 2017 and 100.0% thereafter, together with all accrued and unpaid interest to the date of redemption.
	Senior Unsecured Notes
	In November 2012, AK Steel issued $150.0 aggregate principal of 5.00% Exchangeable Senior Notes due November 2019 (the “Exchangeable Notes”) and generated net proceeds of $144.8 after underwriting discounts and other expenses. AK Steel may not redeem the Exchangeable Notes prior to their maturity date. After August 15, 2019, holders may exchange their Exchangeable Notes at any time. Upon exchange, the Company will be obligated to (i) pay an amount in cash equal to the aggregate principal amount of the Exchangeable Notes to be exchanged and (ii) pay cash, deliver shares of AK Holding common stock or a combination thereof, at the Company’s election, for the remainder, if any, of the exchange obligation in excess of the aggregate principal amount of the Exchangeable Notes being exchanged. Holders may exchange their Exchangeable Notes into shares of AK Holding common stock at their option at an initial exchange rate of 185.1852 shares of AK Holding common stock per $1,000 principal amount of Exchangeable Notes. The initial exchange rate is equivalent to a conversion price of approximately $5.40 per share of common stock, which equates to 27.8 million shares to be used to determine the aggregate equity consideration to be delivered upon exchange, subject to adjustment for certain dilutive effects from potential future events. Holders may exchange their Exchangeable Notes prior to August 15, 2019 only under certain circumstances. The indenture governing the Exchangeable Notes (the “Exchangeable Notes Indenture”) does not contain any financial or operating covenants or restrictions on the payments of dividends, the incurrence of indebtedness or the issuance or repurchase of securities by the Company or its subsidiaries. If the Company undergoes a fundamental change, as defined in Exchangeable Notes Indenture (which, for example, would include various transactions pursuant to which the Company would undergo a change of control), holders may require AK Steel to repurchase the Exchangeable Notes in whole or in part for cash at a price equal to par plus any accrued and unpaid interest. In addition, in the event the Company undergoes a “make-whole fundamental change,” as defined in the Exchangeable Notes Indenture, prior to the maturity date, in addition to requiring AK Steel to repurchase the Exchangeable Notes in whole or in part for cash at a price equal to par plus any accrued and unpaid interest, the exchange rate will be increased in certain circumstances for a holder who elects to exchange its notes in connection with such event. Based on the initial exchange rate, the Exchangeable Notes are exchangeable into a maximum of 37.5 million shares of AK Holding common stock. However, such maximum amount of shares would be exchanged only if, as a result of the occurrence of a “make-whole fundamental change” described above, the Company elects to satisfy the higher exchange rate by delivering to the holders shares of AK Holding common stock in consideration therefor. Although the Exchangeable Notes were issued at par, for accounting purposes the proceeds received from the issuance of the notes are allocated between debt and equity to reflect the fair value of the exchange option embedded in the notes and the fair value of similar debt without the exchange option. As a result, $38.7 of the gross proceeds of the Exchangeable Notes were recorded as an increase in additional paid-in capital with the offsetting amount recorded as a debt discount. The debt discount is being amortized over the term of the Exchangeable Notes using the effective interest method. As of December 31, 2013 and 2012, the remaining unamortized debt discount was $34.3 and $38.2, respectively, and the net carrying amount of the Exchangeable Notes was $115.7 and $111.8, respectively. The portion of underwriting discounts and other fees of $1.4 associated with the exchange option were recorded as a reduction to the gross proceeds included in additional paid-in capital. The carrying amount of the exchange option was $37.3 at December 31, 2013 and 2012. The value of the Exchangeable Notes if exchanged as of December 31, 2013, would have exceeded the principal amount by $35.3.
	AK Steel’s outstanding 7.625% Senior Notes are due May 2020 (the “2020 Notes”). Prior to May 15, 2015, AK Steel may redeem the 2020 Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption. Subsequent to that date, they are redeemable at 103.813% until May 15, 2016, 102.542% thereafter until May 15, 2017, 101.271% thereafter until May 15, 2018 and 100.0% thereafter, together with all accrued and unpaid interest to the date of redemption.
	In March 2012, AK Steel issued $300.0 of 8.375% Senior Notes due April 2022 (the “2022 Notes”) and generated net proceeds of $293.2 after underwriting discounts and other fees. Prior to April 1, 2017, AK Steel may redeem the 2022 Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption. Subsequent to that date, they are redeemable at 104.188% until April 1, 2018, 102.792% thereafter until April 1, 2019, 101.396% thereafter until April 1, 2020 and 100.0% thereafter, together with all accrued and unpaid interest to the date of redemption.
	The 2020 Notes, the 2022 Notes, the Exchangeable Notes and the unsecured IRBs discussed below (collectively, the “Senior Unsecured Notes”) are equal in right of payment. AK Holding fully and unconditionally, jointly and severally, guarantees the payment of interest, principal and premium, if any, on the Senior Unsecured Notes. The indentures governing the 2020 Notes, the 2022 Notes and the IRBs include covenants with customary restrictions on (a) the incurrence of additional debt by certain AK Steel subsidiaries, (b) the incurrence of liens by AK Steel and AK Holding’s other subsidiaries, (c) the amount of sale/leaseback transactions, and (d) the ability of AK Steel and AK Holding to merge or consolidate with other entities or to sell, lease or transfer all or substantially all of the assets of AK Steel and AK Holding to another entity. The indentures governing the Senior Unsecured Notes also contain customary events of default. The Senior Unsecured Notes rank junior in priority to the Secured Notes to the extent of the value of the assets securing such indebtedness.
	During 2013, the Company repurchased an aggregate principal amount of $20.2 and $9.8 of the 2020 Notes and the 2022 Notes, respectively, in private, open market transactions. These repurchases were unsolicited and completed at a discount to the Senior Unsecured Notes’ par value. The Company recognized a gain on the repurchases of $2.9 for the year ended December 31, 2013, which is included in other income (expense).
	Other Financings
	AK Steel has outstanding $73.3 aggregate principal amount of fixed-rate tax-exempt industrial revenue bonds (the “unsecured IRBs”) at December 31, 2013. The weighted-average fixed interest rate of the unsecured IRBs is 6.8%. The unsecured IRBs are unsecured senior debt obligations of AK Steel that are equal in ranking with the other Senior Unsecured Notes. In addition, AK Steel has outstanding $26.8 aggregate principal amount of fixed-rate tax-exempt and variable-rate taxable industrial revenue bonds at December 31, 2013, that are backed by letters of credit.
	In 1997, the Spencer County (IN) Redevelopment District (the “District”) issued $23.0 in taxable tax increment revenue bonds in conjunction with construction of Rockport Works. Proceeds from the bond issue were used by the Company for the acquisition of land and site improvements at the facility.  The source of the District’s scheduled principal and interest payments through maturity in 2017 is a designated portion of the Company’s real and personal property tax payments. The Company is obligated to pay any deficiency in the event its annual tax payments are insufficient to enable the District to make principal and interest payments when due. In 2013, the Company made deficiency payments totaling $1.3. At December 31, 2013, the remaining payments of principal and interest due through the year 2017 total $24.2. The Company includes potential payments due in the coming year under this agreement in its annual property tax accrual.

Pension_and_Other_Postretireme

Pension and Other Postretirement Benefits	12 Months Ended
	Dec. 31, 2013
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
Pension and Other Postretirement Benefits	'
	Pension and Other Postretirement Benefits
	Summary
	The Company provides noncontributory pension and various healthcare and life insurance benefits to a significant portion of its employees and retirees.  Benefits are provided through defined benefit and defined contribution plans administered by the Company, as well as multiemployer plans for certain union members. The pension plan is not fully funded and, based on current actuarial assumptions, the Company plans to contribute approximately $205.0 to the master pension trust during 2014 (of which $41.3 was contributed in January 2014), approximately $105.0 in 2015 and approximately $65.0 in 2016. The Company made $181.1 in contributions during 2013.  In July 2013, the Company made payments to Voluntary Employees Beneficiary Association (“VEBA”) trusts totaling $30.8 pursuant to settlements of class actions filed on behalf of certain retirees from the Company’s Butler Works and Zanesville Works relating to the Company’s other postretirement benefit (“OPEB”) obligations to such retirees. This included the final payment to the Butler VEBA trust, and effective January 1, 2015, all future OPEB obligations for these Butler Works retirees will become the responsibility of the Butler VEBA trust. The Company expects to make OPEB payments, after receipt of Medicare subsidy reimbursements, of approximately $65.3 and a payment to the Zanesville VEBA trust of $3.1 in 2014.
	Plan Obligations
	The information below include amounts calculated based on benefit obligation and asset valuation measurement dates of December 31, 2013 and 2012.
		Pension Benefits								Other Benefits
		2013				2012				2013			2012
	Change in benefit obligations:
	Benefit obligations at beginning of year	$	3,759.40			$	3,539.50			$	602		$	713.2
	Service cost	2.4				3.2				4.7			4.6
	Interest cost	138.8				160.2				21			31.5
	Plan participants’ contributions	—				—				27			28.9
	Actuarial loss (gain)	(214.8		)		364.2				(54.3		)	35.9
	Amendments	6				3.5				—			(87.4		)
	Contributions to Butler and Zanesville retirees’ VEBA trusts	—				—				(30.8		)	(31.7		)
	Benefits paid	(311.4		)		(311.3		)		(95.6		)	(101.4		)
	Medicare subsidy reimbursement received	—				—				5.2			8.4
	Foreign currency exchange rate changes	0.2				0.1				—			—
	Benefit obligations at end of year	$	3,380.60			$	3,759.40			$	479.2		$	602
	Change in plan assets:
	Fair value of plan assets at beginning of year	$	2,591.10			$	2,377.90			$	—		$	—
	Actual gain on plan assets	337.7				347.8				—			—
	Employer contributions	191.1				176.7				63.4			64.1
	Plan participants’ contributions	—				—				27			28.9
	Benefits paid	(311.4		)		(311.3		)		(95.6		)	(101.4		)
	Medicare subsidy reimbursement received	—				—				5.2			8.4
	Fair value of plan assets at end of year	$	2,808.50			$	2,591.10			$	—		$	—
	Funded status	$	(572.1	)		$	(1,168.3	)		$	(479.2	)	$	(602.0	)
	Amounts recognized in the consolidated balance sheets:
	Current liabilities	$	(17.5	)		$	(5.7	)		$	(68.4	)	$	(102.9	)
	Noncurrent liabilities	(554.6		)		(1,162.6		)		(410.8		)	(499.1		)
	Total	$	(572.1	)		$	(1,168.3	)		$	(479.2	)	$	(602.0	)
	Amounts recognized in accumulated other comprehensive income, before tax:
	Actuarial loss (gain)	$	(16.7	)		$	374.2			$	(19.8	)	$	36.8
	Prior service cost (credit)	18.5				16.3				(318.4		)	(398.4		)
	Total	$	1.8			$	390.5			$	(338.2	)	$	(361.6	)
	The accumulated benefit obligation for all defined benefit pension plans was $3,362.1 and $3,740.5 at December 31, 2013 and 2012. All of the Company’s pension plans have an accumulated benefit obligation in excess of plan assets. The amounts included in current liabilities represent only those amounts expected to be paid in the next year associated with unfunded pension and OPEB benefit plans.
	Assumptions used to value benefit obligations and determine pension and OPEB expense (income) are as follows:
		Pension Benefits									Other Benefits
		2013			2012			2011			2013		2012			2011
	Assumptions used to determine benefit obligations at December 31:
	Discount rate	4.53	%		3.85	%		4.74	%		4.48	%	3.77	%		4.72	%
	Rate of compensation increase	4	%		4	%		4	%		4	%	4	%		4	%
	Subsequent year healthcare cost trend rate										7	%	7.5	%		7.5	%
	Ultimate healthcare cost trend rate										4.5	%	4.5	%		4.5	%
	Year ultimate healthcare cost trend rate begins										2019		2019			2018
	Assumptions used to determine pension and OPEB expense (income) for the year ended December 31:
	Discount rate	3.85	%		4.74	%		5.36	%		3.77	%	4.72	%		5.18	%
	Expected return on plan assets	7.25	%		8	%		8.5	%
	Rate of compensation increase	4	%		4	%		4	%		4	%	4	%		4	%
	The discount rate is determined by finding a hypothetical portfolio of individual high-quality corporate bonds available at the measurement date and whose coupon and principal payments were sufficient to satisfy the plans’ expected future benefit payments as defined for the projected benefit obligation.  The discount rate is the single rate that is equivalent to the average yield on that hypothetical portfolio of bonds.
	Assumed healthcare cost trend rates generally have a significant effect on the amounts reported for healthcare plans.  However, changes in these OPEB assumptions are not expected to have a material effect on the Company as a result of the existence of caps on the share of benefits that are paid by the Company. As of December 31, 2013, a one-percentage-point change in the assumed healthcare cost trend rates would have the following effects:
		One Percentage Point
		Increase				Decrease
	Effect on total service cost and interest cost components	$	0.1			$	(0.1	)
	Effect on postretirement benefit obligation	3.3				(3.2		)
	The following presents estimated future benefit payments to beneficiaries:
		Pension				Other				Medicare
		Plans				Benefits				Subsidy
						(a)				(a)
	2014	$	315.6			$	70.7			$	(5.4	)
	2015	299.1				49.3				(3.7		)
	2016	281.5				44.6				(3.4		)
2017	299				41.9				(3.4		)
2018	261.1				39.8				(3.3		)
2019 through 2023	1,179.50				171.8				(15.9		)
(a)	The amounts shown do not include the lump sum payments to the VEBA trust related to the Zanesville Retiree Settlement.  These amounts reflect the fact that the Company will have eliminated its OPEB liability related to the group of retirees covered by the Butler Retiree Settlement after 2014 and the Zanesville Retiree Settlement after 2015.
Plan Assets
Pension assets are invested in the master pension trust and are comprised primarily of investments in indexed and actively-managed funds. A fiduciary committee establishes the target asset mix and monitors asset performance.  The master pension trust’s projected long-term rate of return is determined by the AK Steel master pension trust asset allocation, which is based on the investment policy statement, and long-term capital market return assumptions provided by an investment manager for the master pension trust.
The Company has developed an investment policy which takes into account the liquidity requirements, expected investment return, expected asset risk, as well as standard industry practices. The target asset allocation for the plan assets is 60% equity, 38% fixed income, and 2% cash.  Equity investments consist of individual securities and common/collective trusts with equity investment strategies diversified across multiple industry sectors and company market capitalization within specific geographical investment strategies. Fixed income investments consist of individual securities and common/collective trusts, which invest primarily in investment-grade and high-yield corporate bonds and U.S. treasury securities. The fixed income investments are diversified as to ratings, maturities, industries and other factors. The plan assets contain no significant concentrations of risk related to individual securities or industry sectors. The plan has no direct investments in the Company’s common stock or fixed income securities.
The following table sets forth by level within the fair value hierarchy a summary of the plan’s investments measured at fair value on a recurring basis at December 31, 2013 and 2012. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. See Note 15 for more information on the determination of fair value.
		Quoted Prices								Significant Other							Significant
		in Active								Observable Inputs							Unobservable
		Markets for															Inputs
		Identical Assets
		(Level 1)								(Level 2)							(Level 3)						Total
		2013				2012				2013			2012				2013			2012			2013		2012
Equity Investments:
U.S. securities		$	176.6			$	108.1			$	—		$	—			$	—		$	—		$	176.6	$	108.1
U.S. common/collective trusts		—				—				840.5			808.3				—			—			840.5		808.3
EAFE common/collective trusts		—				—				277.6			256.8				—			—			277.6		256.8
Emerging market securities		79.4				60.9				—			—				—			—			79.4		60.9
Emerging market common/collective trusts		—				—				128.1			134.7				—			—			128.1		134.7
Global investments		—				—				230.8			187.1				—			—			230.8		187.1
Fixed Income Investments:
U.S. investment-grade corporate common/collective trusts		—				—				378.4			333.4				—			—			378.4		333.4
U.S. treasuries common/collective trusts		—				—				88.1			98.4				—			—			88.1		98.4
Mortgage-backed common/collective trusts		—				—				20.5			15.6				—			—			20.5		15.6
Global investments		—				—				350.8			359.6				—			—			350.8		359.6
U.S. high-yield corporate securities		—				—				191.6			175				—			—			191.6		175
Other Investments:
Private equity funds (a)		—				—				—			—				0.6			3.2			0.6		3.2
Cash and cash equivalents		45.5				50				—			—				—			—			45.5		50
Total		$	301.5			$	219			$	2,506.40		$	2,368.90			$	0.6		$	3.2		$	2,808.50	$	2,591.10
(a)	Consists of private equity funds that have no remaining capital commitments due from the Company.
The following sets forth activity for Level 3 assets for 2013 and 2012:
Level 3 Assets		Private Equity Funds
December 31, 2011		$	2.5
Unrealized gains		1.3
Distribution to master pension trust		(0.6		)
December 31, 2012		$	3.2
Distribution to master pension trust		(2.6		)
December 31, 2013		$	0.6
Periodic Benefit Costs
The components of pension and OPEB expense (income) for the years 2013, 2012 and 2011 are as follows:
	Pension Benefits											Other Benefits
	2013				2012				2011			2013				2012			2011
Components of pension and OPEB expense (income):
Service cost	$	2.4			$	3.2			$	3.2		$	4.7			$	4.6		$	4.2
Interest cost	138.8				160.2				180.8			21				31.5			37.9
Expected return on plan assets	(184.5		)		(188.3		)		(207.5		)	—				—			—
Amortization of prior service cost (credit)	3.8				3.8				4			(80.0		)		(77.4		)	(76.6		)
Reversal of prior amortization related to Zanesville and Butler Retiree Settlements	—				—				—			—				2.5			14.2
Recognized net actuarial loss (gain):
Annual amortization	23.6				24.5				18.8			2.4				0.1			(1.0		)
Pension corridor charge	—				157.3				268.1			—				—			—
Settlement gain	(0.8		)		—				—			—				—			(14.0		)
Pension and OPEB expense (income)	$	(16.7	)		$	160.7			$	267.4		$	(51.9	)		$	(38.7	)	$	(35.3	)
In July 2009, the Company reached a final settlement (the “Middletown Retiree Settlement”) of a class action filed on behalf of certain retirees from the Company’s Middletown Works relating to the Company’s OPEB obligations to such retirees. Under terms of the Middletown Retiree Settlement, the Company has transferred to a VEBA trust all OPEB obligations owed to the covered retirees under the Company’s applicable health and welfare plans and has no further liability for any claims incurred by those retirees. For accounting purposes, a settlement of the Company’s OPEB obligations related to the Middletown Retiree Settlement was deemed to have occurred in the first quarter of 2011 when the Company made the final payment to the VEBA trust created under the terms of that settlement. In 2011, the Company recognized the settlement accounting and recorded a non-cash gain of $14.0 in the Consolidated Statements of Operations. The amount recognized was prorated based on the portion of the total liability as of March 2008 that was settled pursuant to the Middletown Retiree Settlement.
In January 2011, the Company reached a final settlement agreement (the “Butler Retiree Settlement”) of a class action filed on behalf of certain retirees from the Company’s Butler Works relating to the Company’s OPEB obligations to such retirees. Pursuant to the Butler Retiree Settlement, AK Steel agreed to continue to provide company-paid health and life insurance to class members through December 31, 2014, and has made combined lump sum payments totaling $91.0 to a VEBA trust and to plaintiffs’ counsel, with the final payment made in 2013. Effective January 1, 2015, AK Steel will transfer to the VEBA trust all OPEB obligations owed to the class members under the Company’s applicable health and welfare plans and will have no further liability for OPEB benefits after December 31, 2014. The effect of the settlement on the Company’s total OPEB liability (prior to any funding of the VEBA trust) was an increase in that liability of approximately $29.6 in 2011. With respect to this increase, a one-time, pre-tax charge of $14.2 was recorded in 2011 to reverse previous amortization of the prior plan amendment. For accounting purposes, a settlement of the Company’s OPEB obligations will be deemed to have occurred when the Company makes the final benefit payments in 2014.
In December 2012, the Company reached a final settlement agreement (the “Zanesville Retiree Settlement”) of a class action filed on behalf of certain retirees from the Company’s Zanesville Works relating to the Company’s OPEB obligations to such retirees. Pursuant to the Zanesville Retiree Settlement, AK Steel agreed to continue to provide company-paid health and life insurance to class members through December 31, 2015, and to make combined lump sum payments totaling $10.6 to a VEBA trust and to plaintiffs’ counsel over three years. The first payments of $4.4 were made in July 2013. Effective January 1, 2016, AK Steel will transfer to the VEBA trust all OPEB obligations owed to the class members under the Company’s applicable health and welfare plans and will have no further liability for any claims incurred by the class members after December 31, 2015, relating to their OPEB obligations. The effect of the settlement on the Company’s total OPEB liability (prior to any funding of the VEBA trust) was an increase in that liability of approximately $3.0 in 2012. With respect to this increase, a one-time, pre-tax charge of $3.8 was recorded in 2012 for legal fees and to reverse previous amortization of the prior plan amendment.
During 2013, the Company performed a remeasurement of an unfunded supplemental retirement plan and recognized a settlement gain as a result of lump sum benefit payments made to retired participants.
The estimated net gain and prior service cost for the defined benefit pension plans that will be amortized from accumulated other comprehensive income into pension and OPEB expense (income) over the next fiscal year are $(4.1) and $4.2, respectively.  The estimated net gain and prior service credit for the other postretirement benefit plans that will be amortized from accumulated other comprehensive income into pension and OPEB expense (income) over the next fiscal year are $(1.3) and $(73.2), respectively.
Defined Contribution Plans
All employees are eligible to participate in various defined contribution plans.  Certain of these plans have features with matching contributions or other company contributions based on Company results. Total expense related to these plans was $11.5, $11.6 and $12.4 in 2013, 2012 and 2011, respectively.
Multiemployer Plans
The Company contributes to multiemployer pension plans under the terms of collective bargaining agreements that cover certain union-represented employees. The risks of participating in these multiemployer plans are different from single employer plans in the following aspects:
•	Assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers.
•	If a participating employer stops contributing to a plan, the unfunded obligations of the plan may be borne by the remaining participating employers.
•	If the Company chooses to stop participating in some of its multiemployer plans, it may be required to pay those plans an amount based on the underfunded status of the plan, referred to as a withdrawal liability.
The Company’s participation in these plans for the years ended December 31, 2013, 2012 and 2011, is outlined in the table below. The Company does not provide more than five percent of the total contributions to any multiemployer plan. Forms 5500 are not yet available for plan years ending in 2013.
Pension Fund		EIN/Pension Plan Number		Pension Protection Act Zone Status (a)				FIP/RP Status Pending/Implemented (b)		Contributions										Surcharge Imposed (c)		Expiration Date of Collective Bargaining Agreement
				2013		2012				2013			2012				2011
Steelworkers Pension Trust		23-6648508/499		Green		Green		No		$	7.3		$	7			$	7.2		No		3/31/2014 to 3/1/2015 (d)
IAM National Pension Fund’s National Pension Plan		51-6031295/002		Green		Green		No		14.8			12.6				12.3			No		9/15/2014 to 10/1/2016 (e)
Other (f)										—			—				0.5
										$	22.1		$	19.6			$	20
(a)	The most recent Pension Protection Act zone status available in 2013 and 2012 is for each plan’s year-end at December 31, 2012 and 2011, respectively. The zone status is based on information that the Company received from the plan and is certified by the plan’s actuary. Generally, plans in the red zone are less than 65% funded, plans in the yellow zone are between 65% and 80% funded, and plans in the green zone are at least 80% funded. The Steelworkers Pension Trust and IAM National Pension Fund’s National Pension Plan elected funding relief under section 431(b)(8) of the Internal Revenue Code and section 304(b)(8) of the Employment Retirement Income Security Act of 1974 (ERISA). This election allows those plans’ investment losses for the plan year ended December 31, 2008, to be amortized over 29 years for funding purposes.
(b)	The “FIP/RP Status Pending/Implemented” column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented, as defined by ERISA.
(c)	The surcharge represents an additional required contribution due as a result of the critical funding status of the plan.
(d)	The Company or its AK Tube subsidiary is a party to three collective bargaining agreements (at its Ashland Works, Mansfield Works and at the AK Tube Walbridge plant) that require contributions to the Steelworkers Pension Trust. The labor contract for approximately 280 hourly employees at Mansfield Works expires on March 31, 2014. The labor contract for approximately 90 hourly employees at the AK Tube Walbridge, OH plant expires January 22, 2015. The labor contract for approximately 820 hourly employees at the Ashland Works expires on March 1, 2015.
(e)	The Company is a party to three collective bargaining agreements (at its Middletown Works, Zanesville Works and Butler Works) that require contributions to the IAM National Pension Fund’s National Pension Plan. The labor contract for approximately 1,650 hourly employees at Middletown Works expires on September 15, 2014. The labor contract for approximately 160 hourly employees at Zanesville Works expires on May 20, 2015. The labor contract for approximately 1,200 hourly employees at Butler Works expires on October 1, 2016.
(f)	The Company was a party to a collective bargaining agreement at its former Ashland coke plant that required contributions to the PACE Industry Union-Management Pension Fund. The Company has now withdrawn from this plan and paid the withdrawal liability of $1.8 in 2012.

Operating_Leases

Operating Leases	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Operating Leases	'
	Operating Leases
	Rental expense was $27.0, $28.0 and $24.7 for 2013, 2012 and 2011, respectively. At December 31, 2013, obligations to make future minimum lease payments were as follows:
	2014	$	8.9
	2015	7.1
	2016	5
	2017	4.7
	2018	4.3
	2019 and thereafter	7.3
	Total minimum lease payments	$	37.3
	The Company leases its corporate headquarters building in West Chester, Ohio.  The initial term of the lease for the building expires in 2019 and there are two five-year options to extend the lease.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments	'
	Commitments
	The principal raw materials required for the Company’s steel manufacturing operations are iron ore, coal, coke, chrome, nickel, silicon, manganese, zinc, limestone, and carbon and stainless steel scrap.  The Company also uses large volumes of natural gas, electricity and industrial gases in its steel manufacturing operations.  In addition, the Company purchases carbon steel slabs from other steel producers to supplement the production from its own steelmaking facilities.  The Company makes most of its purchases of iron ore, coal, coke and industrial gases at negotiated prices under annual and multi-year agreements.  The iron ore agreements typically have a variable-price mechanism by which the price of iron ore is adjusted quarterly, based on reference to a historical iron ore index. The Company typically makes purchases of carbon steel slabs, carbon and stainless steel scrap, natural gas, a majority of its electricity, and other raw materials at prevailing market prices, which are subject to price fluctuations in accordance with supply and demand.  The Company enters into financial instruments designated as hedges with respect to some purchases of energy and certain raw materials, the prices of which may be subject to volatile fluctuations.
	The Company has entered into long-term purchase agreements with affiliates of SunCoke to purchase approximately 1.1 million tons of metallurgical grade coke annually for use in the Company’s blast furnaces at Ashland and Middletown Works. Approximately half of this total will be supplied from SunCoke Middletown, a consolidated variable interest entity.  The Company also will benefit under those agreements from electricity co-generated from the production of the coke.
	At December 31, 2013, commitments for future capital investments totaled approximately $24.1, all of which are expected to be incurred in 2014.

Environmental_and_Legal_Contin

Environmental and Legal Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Environmental and Legal Contingencies	'
	Environmental and Legal Contingencies
	Environmental Contingencies
	Domestic steel producers, including AK Steel, are subject to stringent federal, state and local laws and regulations relating to the protection of human health and the environment.  Over the past three years, the Company has expended the following for environmental-related capital investments and environmental compliance:
		2013			2012			2011
	Environmental-related capital investments	$	1.6		$	1		$	1.7
	Environmental compliance costs	101.1			101.6			106.4
	AK Steel and its predecessors have been conducting steel manufacturing and related operations since 1900. Although the Company believes its operating practices have been consistent with prevailing industry standards during this time, hazardous materials may have been released in the past at one or more operating sites or third-party sites, including operating sites that the Company no longer owns. To the extent reasonably estimable, the Company has 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. In the case of sites involving governmentally-required investigations, that typically occurs only after the investigation is complete and the nature and scope of the remediation is better understood. In general, the material components of these accruals include the costs associated with investigations, delineations, risk assessments, remedial work, governmental response and oversight costs, site monitoring, and preparation of reports to the appropriate environmental agencies. Liabilities recorded on the Consolidated Balance Sheets for such estimated probable costs relating to environmental matters are presented below:
		2013			2012
	Accrued liabilities	$	9.5		$	19.6
	Other non-current liabilities	34.1			27.4
	The ultimate costs to the Company with respect to each site cannot be predicted with certainty because of the evolving nature of the investigation and remediation process. Rather, to develop the estimates of the probable costs, the Company must make certain assumptions. The most significant of these assumptions relate to 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 of future expenditures are not discounted to their present value. To the extent that the Company has been able to reasonably estimate its future liabilities, the Company does not believe that there is a reasonable possibility that a loss or losses exceeding the amounts accrued will be incurred in connection with the environmental matters discussed below that would, either individually or in the aggregate, have a material adverse effect on the Company’s consolidated financial condition, results of operations or cash flows. However, since amounts recognized in the consolidated financial statements in accordance with accounting principles generally accepted in the United States 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 those currently recorded in the Company’s consolidated financial statements.
	Except as expressly noted below, the Company does not currently anticipate any material effect on the Company’s consolidated financial position, results of operations or cash flows as a result of its compliance with current environmental regulations. Moreover, because all domestic steel producers operate under the same set of federal environmental regulations, the Company does not believe that it is disadvantaged relative to its domestic competitors by the need to comply with these regulations. Some foreign competitors may benefit from less stringent environmental requirements in the countries in which they produce, resulting in lower compliance costs and providing those foreign competitors with a cost advantage on their products.
	Pursuant to the Resource Conservation and Recovery Act (“RCRA”), which governs the treatment, handling and disposal of hazardous waste, the 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. AK Steel’s major steelmaking facilities are subject to RCRA inspections by environmental regulators. While the Company 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 conferred by the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”), the EPA and state environmental authorities have conducted site investigations at certain of AK Steel’s facilities and other third-party facilities, portions of which previously may have been used for disposal of materials that are currently subject to regulation. The results of these investigations are still pending, and AK Steel could be directed to expend funds for remedial activities at the former disposal areas. Because of the uncertain status of these investigations, however, the Company cannot reliably predict whether or when such expenditures might be required, their magnitude or the timeframe during which these potential costs would be incurred.
	As previously reported, on July 27, 2001, AK Steel received a Special Notice Letter from the EPA requesting that AK Steel agree to conduct a Remedial Investigation/Feasibility Study (“RI/FS”) and enter into an administrative order on consent pursuant to Section 122 of CERCLA regarding the former Hamilton Plant located in New Miami, Ohio. The Hamilton Plant ceased operations in 1990, and all of its former structures have been demolished and removed. Although AK Steel did not believe that a site-wide RI/FS was necessary or appropriate, in April 2002 it entered into a mutually agreed-upon administrative order on consent to perform such an investigation and study of the Hamilton Plant site. The site-wide investigation portion of the RI/FS has been submitted. A supplemental study is projected to be completed in early 2014. AK Steel currently has accrued $0.7 for the remaining cost of the RI/FS. Until the RI/FS is completed, AK Steel cannot reliably estimate the additional costs, if any, associated with any potentially required remediation of the site or the timeframe during which these potential costs would be incurred.
	As previously reported, on September 30, 1998, AK Steel’s 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 Mansfield Works that allegedly could be sources of contamination. A site investigation began in November 2000 and is continuing. AK Steel cannot reliably estimate at this time how long it will take to complete this site investigation. AK Steel currently has accrued approximately $1.1 for the projected cost of the study at Mansfield Works. Until the site investigation is completed, AK Steel cannot reliably estimate the additional costs, if any, associated with any potentially required remediation of the site or the timeframe during which these potential costs would be incurred.
	As previously reported, on July 23, 2007, and on December 9, 2008, the EPA issued Notices of Violation (“NOVs”) with respect to the coke plant at AK Steel’s Ashland Works (the “Ashland Coke Plant”) alleging violations of pushing and combustion stack limits. Additionally, on November 9, 2011, the EPA issued an NOV associated with self-reported deviations from 2008 through 2010. In 2007, the Company began investigating the pushing and combustion stack claims and working with the EPA to attempt to resolve them through the negotiation of a Consent Decree that assumed the Ashland Coke Plant would continue to operate. On June 21, 2011, however, the Company permanently ceased production at the Ashland Coke Plant. The Company, EPA and the Commonwealth of Kentucky have agreed to the terms of a Consent Decree which was approved by the United States District Court for the Eastern District of Kentucky on November 5, 2013 resolving all of these NOVs. The settlement terms include a payment of a civil penalty by AK Steel in the amount of $1.7 and the agreement by AK Steel to undertake certain supplemental environmental capital projects which are expected to cost approximately $2.0. The civil penalty was paid in 2013 and the costs related to the capital projects are expected to be incurred in 2014.
	As previously noted, on September 26, 2012, the EPA issued an order under Section 3013 of RCRA requiring the Company to develop a plan for investigation of four areas at AK Steel’s Ashland Works Coke Plant. A site investigation plan was submitted to the EPA on October 25, 2012 and revised on March 21, 2013. On August 27, 2013, the EPA issued a comment letter disapproving the site investigation plan submitted by the Company. On September 19, 2013, the Company met with the EPA and the Company believes that all material disagreements with the EPA concerning the proposed site investigation plan were resolved at that time. The Company submitted a revised investigation plan on October 23, 2013 which it believes is consistent with the parties’ discussion on September 19, 2013. AK Steel is awaiting approval by the EPA of that plan. AK Steel cannot reliably estimate at this time how long it will take to complete the site investigation. AK Steel currently has accrued approximately $0.5 for the projected cost of the investigation. Until the site investigation is completed, AK Steel cannot reliably estimate the additional costs, if any, associated with any potentially required remediation of the site or the timeframe during which these potential costs would be incurred.
	As previously reported, on August 3, 2011, September 29, 2011, and June 28, 2012, the EPA issued NOVs with respect to the coke plant at AK Steel’s Middletown Works alleging violations of pushing and combustion stack limits. The Company is investigating these claims and is working with the EPA to attempt to resolve them. AK Steel believes it will reach a settlement in this matter, but it cannot be certain that a settlement will be reached and cannot reliably estimate at this time how long it will take to reach a settlement or what all of its terms might be. AK Steel will vigorously contest any claims which cannot be resolved through a settlement. Until it has reached a settlement with the EPA or the claims that are the subject of the NOVs are otherwise resolved, AK Steel cannot reliably estimate the costs, if any, associated with any potentially required operational changes at the battery or the timeframe over which any potential costs would be incurred.
	As previously reported, on July 15, 2009, AK Steel and the Pennsylvania Department of Environmental Protection (“PADEP”) entered into a Consent Order and Agreement (the “Consent Order”) to resolve an alleged unpermitted discharge of wastewater from the closed Hillside Landfill at the former Ambridge Works. Under the terms of the Consent Order, AK Steel paid a penalty and also agreed to implement various corrective actions, including an investigation of the area where activities were conducted regarding the landfill, submission of a plan to collect and treat surface waters and seep discharges, and upon approval from PADEP, implementation of that plan. The Company has accrued $2.2 for the current phase of remedial work required under the Consent Order. However, the design plan for this phase has not yet been developed or approved. Until that design plan is approved, the Company cannot reliably determine the actual cost of this phase, but it is expected to be at least the amount of the current accrual. The Company currently estimates that the remaining work required for this phase will be completed in 2015, but that estimated timeframe is subject to the potential for delays, such as delays due to work plan approval and/or permitting delays. Additional work in the form of monitoring likely will be required after completion of the current phase, but the Company cannot reliably determine the cost of that work or the timeframe for its completion until the design phase has been approved.
	As previously reported, on June 29, 2000, the United States filed a complaint on behalf of the EPA against AK Steel in the U.S. District Court for the Southern District of Ohio (the “Court”), Case No. C-1-00530, for alleged violations of the Clean Air Act, the Clean Water Act and RCRA at the Middletown Works. Subsequently, the State of Ohio, the Sierra Club and the National Resources Defense Council intervened. On May 15, 2006, a Consent Decree in Partial Resolution of Pending Claims (the “Consent Decree”) was entered by the Court. Under the Consent Decree, the Company paid a civil penalty and performed a supplemental environmental project to remove ozone-depleting refrigerants from certain equipment. The Company further agreed to undertake a comprehensive RCRA facility investigation at its Middletown Works and, as appropriate, complete a corrective measures study. In accordance with the Consent Decree, the Company also was required to implement certain RCRA corrective action interim measures to address polychlorinated biphenyls (“PCBs”) in sediments and soils relating to Dicks Creek and certain other specified surface waters, adjacent floodplain areas and other previously identified geographic areas. The Company has completed the remedial activity at Dicks Creek, but continues to work on the RCRA facility investigation and certain interim measures. The Company currently has accrued $13.9 for the cost of known work required under the Consent Decree for the RCRA facility investigation and remaining interim measures.
	As previously reported, on October 17, 2012, the EPA issued an NOV and Notice of Intent to File a Civil Administrative Complaint to AK Steel’s Mansfield Works alleging violations of RCRA primarily relating to the Company’s management of electric arc furnace dust at the facility. The Company is investigating these claims and is working with the EPA to attempt to resolve them. The NOV proposed a civil penalty of approximately $0.3. AK Steel believes it will reach a settlement in this matter, but it cannot be certain that a settlement will be reached and cannot reliably estimate at this time how long it will take to reach a settlement or what all of its terms might be. AK Steel will vigorously contest any claims which cannot be resolved through a settlement.
	In addition to the foregoing matters, AK Steel is or may be involved in proceedings with various regulatory authorities that may require AK Steel to pay fines, comply with more rigorous standards or other requirements or incur capital and operating expenses for environmental compliance. The Company believes that the ultimate disposition of the proceedings will not have, individually or in the aggregate, a material adverse effect on its consolidated financial condition, results of operations or cash flows.
	Legal Contingencies
	As previously reported, since 1990, AK Steel (or its predecessor, Armco Inc.) has 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 a current or former AK Steel facility. The majority of asbestos cases pending in which AK Steel is 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.
	Information on asbestos cases pending at December 31, 2013, is presented below:
			Asbestos Cases Pending at
			December 31, 2013
	Cases with specific dollar claims for damages:
	Claims up to $0.2			121
	Claims above $0.2 to $5.0			6
	Claims above $5.0 to $15.0			2
	Claims above $15.0 to $20.0			2
	Total claims with specific dollar claims for damages (a)			131
	Cases without a specific dollar claim for damages			305
	Total asbestos cases pending			436
	(a)	Involve a total of 2,387 plaintiffs and 17,623 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 AK Steel. In fact, it usually is not even possible at the outset to determine which of the plaintiffs actually will pursue a claim against AK Steel. Typically, that can only be determined through written interrogatories or other discovery after a case has been filed. Thus, in a case involving multiple plaintiffs and multiple defendants, AK Steel initially only accounts for the lawsuit as one claim against it. After AK Steel has determined through discovery whether a particular plaintiff will pursue a claim against it, it makes an appropriate adjustment to statistically account for that specific claim. It has been AK Steel’s experience to date that only a small percentage of asbestos plaintiffs ultimately identify AK Steel 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. Set forth below is a chart showing the number of new claims filed (accounted for as described above), the number of pending claims disposed of (i.e., settled or otherwise dismissed), and the approximate net amount of dollars paid on behalf of AK Steel in settlement of asbestos-related claims in 2013, 2012 and 2011.
			2013			2012			2011
	New Claims Filed		42			50			31
	Pending Claims Disposed Of		39			24			44
	Total Amount Paid in Settlements		$	1		$	0.8		$	0.7
	Since the onset of asbestos claims against AK Steel in 1990, five asbestos claims against it have proceeded to trial in four separate cases. All five concluded with a verdict in favor of AK Steel. AK Steel intends to continue to vigorously defend the asbestos claims asserted against it. Based upon its present knowledge, and the factors set forth above, the Company believes it is unlikely that the resolution in the aggregate of the asbestos claims against AK Steel will have a materially adverse effect on the Company’s consolidated results of operations, cash flows or financial condition. However, predictions as to 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 uncertainties surrounding the litigation process from jurisdiction to jurisdiction and from case to case, (4) the type and severity of the disease alleged to be suffered by each claimant, and (5) the potential for enactment of legislation affecting asbestos litigation.
	As previously reported, on October 20, 2009, William Schumacher filed a purported class action against the AK Steel Corporation Retirement Accumulation Pension Plan, or AK RAPP, and the AK Steel Corporation Benefit Plans Administrative Committee in the United States District Court for the Southern District of Ohio, Case No. 1:09cv794. The complaint alleges that the method used under the AK RAPP to determine lump sum distributions does not comply with ERISA and the Internal Revenue Code and resulted in underpayment of benefits to him and the other class members. The plaintiff and the other individuals on whose behalf the plaintiff filed suit were excluded by the Court in 2005 from similar litigation previously reported and now resolved (the class action litigation filed January 2, 2002 by John D. West) based on previous releases of claims they had executed in favor of the Company. There were a total of 92 individuals who were excluded from the prior litigation. On January 24, 2011, this case was certified as a class action. On December 12, 2011, the Court entered a final judgment in an amount slightly in excess of $3.0, which included pre-judgment interest at the statutory rate through that date. The defendants filed an appeal from that final judgment to the United States Court of Appeals for the Sixth Circuit and the plaintiff filed an appeal on the issue of how the pre-judgment interest was calculated. On March 28, 2013, the Court of Appeals issued an opinion in which it upheld the District Court’s decision with respect to liability and reversed and remanded the District Court's decision with respect to pre-judgment interest. On May 29, 2013, Plaintiffs’ counsel filed a motion for a determination of the new rate for pre-judgment interest with respect to the final judgment amount of $3.0. On November 13, 2013, the District Court entered final judgment in the amount of $4.4, including pre-judgment and post-judgment interest, in accordance with its determination of the pre-judgment interest issue. That judgment was paid on November 21, 2013 from the Company’s pension trust. On October 14, 2013, Plaintiffs’ counsel filed a motion requesting an award of attorney fees of $1.3. The Company opposed that motion. By order dated February 4, 2014, the Court granted in part and denied in part the motion filed by Plaintiffs’ counsel seeking an award of fees. As part of the order, the Court directed the defendants to pay to Plaintiffs’ counsel statutory fees in the amount of approximately $0.6. Because, like the final judgment, any award of attorney fees will be paid out of the Company’s pension trust, the Company has not recorded an accrual related to this matter. Upon payment of such fees (which is expected to be in the first quarter of 2014), this matter will be concluded as to the defendants.
	As previously reported, on October 20, 2005, Judith A. Patrick and another plaintiff filed a purported class action against AK Steel and the AK Steel Corporation Benefit Plans Administrative Committee in the United States District Court for the Southern District of Ohio, Case No. 1:05-cv-681. The complaint alleged that the defendants incorrectly calculated the amount of surviving spouse benefits due to be paid to the plaintiffs under an applicable pension plan. The case subsequently was certified as a class action. Pursuant to a settlement conference called by the District Court, the parties reached a settlement of this matter in 2013, subject to court approval after a fairness hearing. On July 1, 2013, the parties filed a Motion for Preliminary Approval of Class Settlement. An order providing such preliminary approval was entered on July 29, 2013. The District Court held a fairness hearing on November 20, 2013 and on November 22, 2013 entered a final order approving the class action settlement and an order dismissing the litigation with prejudice. Pursuant to the terms of the settlement, the named plaintiffs and other participating class members were paid $1.7 and $0.8 was paid to plaintiffs’ attorneys for fees and costs, for a total payment of $2.5. The settlement payments set forth above were made from the Company’s pension plan trust in the first quarter of 2014. Upon such payments, this matter was concluded.
	As previously reported, in September and October 2008, several companies filed purported class actions in the United States District Court for the Northern District of Illinois against nine steel manufacturers, including AK Holding. The case numbers for these actions are 08CV5214, 08CV5371, 08CV5468, 08CV5633, 08CV5700, 08CV5942 and 08CV6197. An additional action, case number 10CV04236, was filed in the same federal district court on July 8, 2010. 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 filed a motion to transfer the case to the Northern District of Illinois. That motion was granted on March 28, 2012. The plaintiffs in the various pending actions are companies which claim to have purchased steel products, directly or indirectly, from one or more of the defendants and they purport 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 with respect to steel products in the United States. Discovery has commenced. On May 24, 2012, the direct purchaser plaintiffs filed a motion for class certification. On February 28, 2013, the defendants filed a memorandum in opposition to the motion for class certification and motions to exclude the opinions of the plaintiffs’ experts. The motion for class certification and the motions to exclude the opinions of the plaintiffs’ experts are set for an evidentiary hearing on March 15, 2014. No trial date has been set. AK Holding intends to contest this matter vigorously. To date, discovery in this action has proceeded only with respect to issues relating to class certification. Accordingly, the Company does not have adequate information available to determine that a loss is probable or to reliably or accurately estimate its potential loss in the event that the plaintiffs were to prevail. Because the Company has been unable to determine that the potential loss in this case is probable or estimable, it has not recorded an accrual related to this matter. In the event that the Company’s assumptions used to evaluate whether a loss in this matter is either probable or estimable prove to be incorrect or change in future periods, the Company may be required to record a liability for an adverse outcome.
	As previously reported, on August 26, 2009, Consolidation Coal Company (“Consolidation”) filed an action against AK Steel and Neville Coke LLC (“Neville”) in the Court of Common Pleas of Allegheny County, Pennsylvania, Case No. GD-09-14830. The complaint alleged that Consolidation and Neville entered into a contract whereby Consolidation would supply metallurgical coal for use by Neville in its coke making operations. Consolidation asserts that Neville breached the alleged contract when it refused to purchase coal from Consolidation. The complaint also alleges that AK Steel tortiously interfered with the purported contractual and business relationship between Consolidation and Neville. Consolidation sought monetary damages from AK Steel in an amount in excess of $30.0 and monetary damages from Neville in an amount in excess of $20.0. On March 18, 2010, AK Steel and Neville filed their answers to the complaint and discovery commenced. The case previously was set for trial commencing on May 9, 2013, but that trial date was vacated so that the parties could explore the possibility of settlement through commercial terms. The parties reached a settlement which involves a commercial resolution of the dispute and no separate payment of any settlement monies. The parties filed a praecipe to settle and discontinue the litigation on December 16, 2013. As a result, this matter is now concluded.
	As previously reported, on December 31, 2009, Heritage Coal Company LLC, Patriot Coal Corporation and Pine Ridge Coal Company (collectively, “Heritage Coal”) filed a third-party complaint against AK Steel in the Circuit Court of Boone County, West Virginia, naming AK Steel as a third-party defendant in 108 separate personal injury actions. Those actions were consolidated for discovery and pretrial proceedings under Civil Action No. 09-C-212. The various plaintiffs in the underlying actions sought damages allegedly caused by groundwater contamination arising out of certain coal mining operations in West Virginia. In its third-party complaint, Heritage Coal seeks a determination of its potential rights of contribution against AK Steel pursuant to a January 20, 1984 Asset Purchase Agreement between Heritage Coal’s predecessor-in-interest, Peabody Coal Company, as buyer, and AK Steel’s predecessor-in-interest, Armco Inc., as seller, for the sale of certain coal real estate and leasehold interests located in West Virginia, which Heritage alleges included property now the subject of the underlying civil actions. On March 28, 2010, AK Steel entered into a tentative settlement agreement with the plaintiffs and Heritage Coal. The payments made by AK Steel pursuant to this settlement will not be material to the Company’s future financial results. The parties are in the process of documenting and obtaining formal court approval of the settlement, which is expected to be completed in the near future. The settlement will resolve all of the claims raised by Heritage Coal in the third-party complaint and will also release AK Steel from any claims by the plaintiffs in the underlying actions.
	As previously reported, on April 7, 2011, Ruth Abrams filed a shareholder derivative action against AK Holding, each of the current members of its Board of Directors, and the five officers identified in the AK Holding 2010 Proxy Statement (the “2010 Proxy”) as Named Executive Officers. The action was filed in the United States District Court for the District of Delaware, Case No. 1:11-cv-00297-LPS. The complaint alleged that the director defendants and executive defendants breached fiduciary duties of loyalty and care, that the director defendants committed waste, and that the executive defendants were unjustly enriched. More specifically, it alleged that the 2010 Proxy contained false or misleading statements concerning compliance by AK Holding with Section 162(m) of the Internal Revenue Code and the tax deductibility of certain executive compensation paid to the Named Executive Officers. The Complaint sought an injunction requiring correction of the allegedly false statements and preventing future awards under certain benefit plans to the five Named Executive Officers. It also sought an equitable accounting, disgorgement in favor of AK Holding for certain alleged losses, and an award of attorneys’ fees and expenses. After dismissal of the first two complaints filed by Abrams, she filed a Second Amended Complaint on September 4, 2012, adding a new direct claim for coercion and adding and deleting certain factual allegations. On October 2, 2012, the defendants filed motions to dismiss the second amended complaint. On November 13, 2013, the court granted the defendants’ motion to dismiss the second amended complaint with prejudice. Abrams did not appeal that order and the litigation thus now is concluded in favor of the defendants.
	As previously reported, on January 20, 2010, ArcelorMittal France and ArcelorMittal Atlantique et Lorraine (collectively “ArcelorMittal”) filed an action against AK Steel (and two other steel manufacturers) in the United States District Court for the District of Delaware, Case No. 10-050-SLR. The complaint alleges that AK Steel is 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. On March 4, 2010, AK Steel filed an answer in which it denied ArcelorMittal’s claims and raised various affirmative defenses. On that date, AK Steel also filed counterclaims against ArcelorMittal for a declaratory judgment that AK Steel is not infringing the Patent and that the Patent is invalid. Subsequently, the trial court bifurcated 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 AK Steel did not infringe the Patent and that the Patent was invalid. Judgment subsequently was entered in favor of AK Steel and 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 confirming that AK Steel had prevailed on the key claim related to patent infringement and affirming the basis for the jury finding of no infringement. The Court of Appeals reversed, however, certain findings related to 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, pursuant to a petition previously filed by ArcelorMittal and ArcelorMittal USA LLC, the U.S. Patent and Trademark Office reissued the Patent as U.S. Reissue Patent RE44,153 (the “Reissued Patent”). Also on April 16, 2013, ArcelorMittal filed a second action against AK Steel in the United States District Court for the District of Delaware, Case No. 1:13-cv-00685 (the “Second Action”). The complaint filed in the Second Action alleges that AK Steel is infringing the claims of the Reissued Patent and seeks injunctive relief and unspecified compensatory damages. On April 23, 2013, AK Steel 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 favor of AK Steel, confirming that AK Steel’s product does not infringe the original Patent or the Reissued Patent. The Court further ruled that ArcelorMittal’s Reissued Patent was invalid due to ArcelarMittal’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. The defendants opposed the motion. On December 5, 2013, the court issued a memorandum and order denying the motion and entering final judgment in favor of defendants, including AK Steel, 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. AK Steel intends to continue to contest this matter vigorously. At this time, the Company has not made a determination that a loss is probable and it does not have adequate information to reliably or accurately estimate its potential loss in the event that ArcelorMittal were to prevail in its appeal in this dispute. Because the Company has been unable to determine that the potential loss in this case is probable or estimable, it has not recorded an accrual related to this matter. In the event that the Company’s assumptions used to evaluate whether a loss in this matter is either probable or estimable prove to be incorrect or change in future periods, the Company may be required to record a liability for an adverse outcome.
	Trade Cases
	As previously reported, on June 1, 2009, the Chinese Ministry of Commerce (“MOFCOM”) initiated antidumping and countervailing duty investigations of imports of grain-oriented electrical steel (“GOES”) from Russia and the United States. China initiated the investigations based on a petition filed by two Chinese steelmakers. These two steelmakers alleged that AK Steel and Allegheny Technologies Inc. of the United States and Novolipetsk Steel of Russia exported GOES to China at less than fair value, and that the production of GOES in the United States has been subsidized by the U.S. government. On December 9, 2009, MOFCOM issued its preliminary determination that GOES producers in the United States and Russia had been dumping in the China market and that GOES producers in the United States had received subsidies from the U.S. government. The Chinese authorities imposed provisional additional duties on future imports of GOES from Russia and/or the United States to China. On or about April 10, 2010, MOFCOM issued a final determination of dumping and subsidization against GOES producers in the United States and Russia. On September 16, 2010, the Office of the United States Trade Representative (“USTR”) filed a complaint with the World Trade Organization (the “WTO”) against China for violating the WTO’s rules by imposing antidumping and countervailing duties against imports of GOES from the United States. After conducting several rounds of hearings, on June 15, 2012, a panel (“the Panel”) composed by the WTO to decide the case issued its final decision in the case. In its decision, the Panel concluded that MOFCOM imposed antidumping and countervailing duties on imports of GOES from the United States in a manner that was inconsistent with China’s WTO obligations. On July 20, 2012, China filed an appeal of the Panel’s decision to the WTO Appellate Body. On October 18, 2012, the Appellate Body upheld the decisions of the Panel. On November 16, 2012, the WTO Dispute Settlement Body adopted the decisions of the Panel. Subsequently, a WTO Arbitrator determined that China should implement the WTO decision by July 31, 2013. In its final determination issued on July 31, 2013, MOFCOM reduced the countervailing duty rate applicable to AK Steel from 11.7 percent to 3.4 percent and determined that the antidumping duty rate applicable to AK Steel will remain at 7.8 percent, for a total of 11.2 percent. AK Steel does not believe that China has remedied the flaws that the WTO identified in MOFCOM’s material injury finding. Accordingly, AK Steel urged USTR to request, and USTR now has requested, a WTO dispute settlement panel to determine that China has failed to comply with the WTO decision. AK Steel also has urged USTR to ask that WTO Dispute Settlement Body for permission to impose trade sanctions. AK Steel intends to continue to fully support the USTR in this matter.
	On September 18, 2013, AK Steel, along with another domestic producer and the United Steelworkers, filed trade cases against imports of grain-oriented electrical steel (“GOES”) from seven countries. Antidumping (“AD”) petitions were filed against China, the Czech Republic, Germany, Japan, Poland, Russia and South Korea and a countervailing duty (“CVD”) petition was filed against China charging that unfairly traded imports of GOES from those seven countries are causing material injury to the domestic industry. The United States Department of Commerce (“DOC”) initiated the cases on October 24, 2013. On November 19, 2013, the International Trade Commission (“ITC”) made a preliminary determination that there is a reasonable indication that GOES imports caused or threaten to cause material injury. The DOC is expected to make preliminary determinations with regard to dumping and subsidies in the second quarter of 2014, at which point the DOC may impose preliminary duties. If preliminary duties are imposed, covered importers would be required to pay cash deposits to the U.S. Government covering those duties beginning as of the date of the preliminary determination. Those preliminary duties would remain in effect until final determinations are issued. The entire investigation is expected to take approximately one year, with final determinations of whether there have been dumping, subsidization, and injury likely occurring in the fall of 2014.
	On September 30, 2013, AK Steel filed trade cases against imports of non-oriented electrical steel (“NOES”) from six countries. AD petitions were filed against China, Germany, Japan, South Korea, Sweden and Taiwan and CVD petitions were filed against China, South Korea and Taiwan charging that unfairly traded imports of NOES from those six countries are causing material injury to the domestic industry. The DOC initiated the cases on November 7, 2013. On December 3, 2013, the ITC made a preliminary determination that there is a reasonable indication that NOES imports caused or threaten to cause material injury. The DOC is expected make preliminary determinations with regard to dumping and subsidies in the second quarter of 2014, at which point DOC may impose preliminary duties. If preliminary duties are imposed, covered importers would be required to pay cash deposits covering the preliminary duties to the U.S. Government beginning as of the date of the preliminary determination. Those preliminary duties would remain in effect until final determinations are issued. The entire investigation is expected to take approximately one year, with final determinations of whether there have been dumping, subsidization, and injury likely occurring in the fall of 2014.
	Other Contingencies
	In addition to the matters discussed above, there are various pending and potential claims against AK Steel and its subsidiaries involving product liability, commercial, employee benefits and other matters arising in the ordinary course of business. Because of the considerable uncertainties which exist with respect to any claim, it is difficult to reliably or accurately estimate what would be the amount of a loss in the event that a claimant(s) were to prevail. In the event that material assumptions or factual understandings relied upon by the Company to evaluate its exposure with respect to these contingencies prove to be inaccurate or otherwise change in the future, the Company may be required to record a liability for an adverse outcome. To the extent, however, that the Company has been able to reasonably evaluate its potential future liabilities with respect to all of these contingencies, including those described more specifically above, it is the Company’s opinion, unless otherwise noted, that the ultimate liability resulting from these contingencies, individually and in the aggregate, should not have a material effect on the Company’s consolidated financial position, results of operations or cash flows.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	Stockholders’ Equity
	Preferred Stock:  There are 25,000,000 shares of preferred stock authorized; no shares are issued or outstanding.
	Common Stock:  The holders of common stock are entitled to receive dividends when and as declared by the Board of Directors out of funds legally available for distribution.  The holders have one vote per share in respect of all matters and are not entitled to preemptive rights. In November 2012, AK Holding issued 25.3 million shares of common stock at $4.00 per share. Net proceeds received were $96.4 after underwriting discounts and other fees.
	Dividends:  The instruments governing the Company’s outstanding senior debt do not include covenants restricting dividend payments.  The Company’s Credit Facility contains certain restrictive covenants with respect to the Company’s payment of dividends. Under these covenants, dividends are permitted provided (i) availability exceeds $247.5 or (ii) availability exceeds $192.5 and the Company meets a fixed charge coverage ratio of one to one as of the most recently ended fiscal quarter. If the Company cannot meet either of these thresholds, dividends would be limited to $12.0 annually. Currently, the availability under the Credit Facility significantly exceeds $247.5. In July 2012, the Company elected to suspend its dividend program in order to enhance the Company’s financial flexibility and further support capital needs for the business.  Accordingly, although the Company has elected to suspend its dividend program, there currently are no covenant restrictions that would restrict the Company’s ability to declare and pay a dividend to its stockholders. Cash dividends paid in 2012 by the Company to its shareholders were determined to be a return of capital under the United States Internal Revenue Code.
	Share Repurchase Program:  In October 2008, the Board of Directors authorized the Company to repurchase, from time to time, up to $150.0 of its outstanding common stock.  In 2013, 2012 and 2011, the Company did not make any common stock repurchases under this program. As of December 31, 2013, there was $125.6 remaining for repurchase under the Board of Directors’ authorization.

Sharebased_Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-based Compensation	'
	Share-based Compensation
	AK Holding’s Stock Incentive Plan (the “SIP”) permits the granting of nonqualified stock option, restricted stock, performance share and/or restricted stock unit (“RSUs”) awards to Directors, officers and other employees of the Company. Stockholders have approved an aggregate maximum of 19 million shares issuable under the SIP through December 31, 2019, of which 3.0 million are available for future grant as of December 31, 2013.
	The following table summarizes information about share-based compensation expense for the years ended December 31, 2013, 2012 and 2011:
	Share-based Compensation Expense		2013				2012			2011
	Stock options		$	1.5			$	2.4		$	2.3
	Restricted stock		2.9				5.3			5.9
	Restricted stock units issued to Directors		1				0.9			0.9
	Performance shares		4.1				6			5.8
	Pre-tax share-based compensation expense		$	9.5			$	14.6		$	14.9
	Stock Options
	Stock options have a maximum term of ten years and may not be exercised earlier than six months following the date of grant or such other term as may be specified in the award agreement. Stock options granted to officers and key managers vest and become exercisable in three equal installments on the first, second and third anniversaries of the grant date. The exercise price of each option may not be less than the market price of the Company’s common stock on the date of the grant. The Company has not had, and does not have, a policy or practice of repricing stock options to lower the price at which such options are exercisable.
	The Company uses the Black-Scholes option valuation model to value the nonqualified stock options. Historical data regarding stock option exercise behaviors was used to estimate the expected life of options granted based on the period of time that options granted are expected to be outstanding. The risk-free interest rate is based on the Daily Treasury Yield Curve published by the U.S. Treasury on the date of grant. The expected volatility is determined by using a blend of historical and implied volatility. The expected dividend yield is based on the Company’s historical dividend payments. The Company estimates that 5% of the options issued will be forfeited.
	The Company’s estimate of fair value of options granted is calculated as of the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:
			2013				2012			2011
	Expected volatility		57.8% – 68.8%				63.2% – 73.2%			59.7% – 78.0%
	Weighted-average volatility		65.2		%		69.4		%	62.1		%
	Expected term (in years)		2.9-6.4				2.8 – 6.3			2.7 – 6.3
	Risk-free interest rate		0.4% - 1.1%				0.3% - 1.2%			0.4% – 2.6%
	Dividend yield		—		%		2.2		%	1.4		%
	Weighted-average grant-date fair value per share of options granted		$	2.44			$	4.31		$	6.83
	A summary of option activity for the year ended December 31, 2013, is presented below:
	Stock Options			Shares			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
	Outstanding at December 31, 2012			1,819,382			$	14.46
	Granted			502,750			4.58
	Exercised			(15,000	)		4.57
	Canceled			(113,600	)		14.64
	Outstanding at December 31, 2013			2,193,532			12.26			5.9		$	1.9
	Exercisable at December 31, 2013			1,283,599			15.85			4.7		0.1
	Unvested at December 31, 2013			909,933			7.19			7.7		1.8
	Unvested at December 31, 2013 expected to vest			864,436			7.19			7.7		1.7
	The total intrinsic value of stock option awards that were exercised during the years ended December 31, 2013, 2012 and 2011, was $0.0, $0.0 and $0.2, respectively. Intrinsic value is based upon the actual market price on the date of exercise, as determined by the quoted average of the reported high and low sales prices on such date. As of December 31, 2013, there were $0.4 of total unrecognized compensation costs related to non-vested stock options, which costs are expected to be recognized over a weighted-average period of 1.6 years.
	Restricted Stock and Restricted Stock Units
	Restricted stock awards granted to officers and key managers ordinarily are awarded on terms pursuant to which the shares covered by the award vest ratably on the first, second and third anniversaries of the grant.
	Equity-based compensation granted to Directors is comprised entirely of RSUs. Grants of RSUs vest immediately upon grant, but are not settled (i.e., paid out) until one year after the date of the grant, unless deferred settlement is elected. Directors have the option to defer settlement of their RSUs until six months following termination of their service on the Board and also may elect to take distribution of the shares upon settlement in a single distribution or in annual installments not to exceed fifteen years.
	A summary of the activity for non-vested restricted stock awards for the year ended December 31, 2013, is presented below:
	Restricted Stock Awards	Restricted Shares			Weighted- Average Grant Date Fair Value
	Outstanding at December 31, 2012	398,113			$	11.33
	Granted	550,581			4.43
	Vested/restrictions lapsed	(466,641	)		8.14
	Canceled	(48,824	)		8.02
	Outstanding at December 31, 2013	433,229			6.35
	The weighted-average grant date fair value of restricted stock awards granted during the years ended December 31, 2013, 2012 and 2011, was $4.43, $8.78 and $14.47 per share, respectively. The total intrinsic value of restricted stock awards that vested (i.e., restrictions lapsed) during the years ended December 31, 2013, 2012 and 2011, was $2.1, $4.9 and $4.4, respectively. As of December 31, 2013, there were $1.3 of total unrecognized compensation costs related to non-vested restricted stock awards granted under the SIP, which costs are expected to be recognized over a weighted-average period of 1.7 years.
	Performance Shares
	Performance shares are granted to officers and key managers. The awards are earned based upon meeting performance measures over a three-year period. Though a target number of performance shares are awarded on the grant date, the total number of performance shares issued to the participant upon vesting is based on two equally-rated metrics: (i) the Company’s share performance compared to a prescribed compounded annual growth rate and (ii) the Company’s total share return compared to Standard & Poor’s MidCap 400 index.
	The Company’s estimate of fair value of performance shares granted is calculated as of the date of grant using a Monte Carlo simulation model with the following weighted-average assumptions:
			2013				2012			2011
	Company expected volatility		59.2		%		69.4		%	89		%
	S&P’s MidCap 400 index expected volatility		34.7		%		42.2		%	52.4		%
	Risk-free interest rate		0.4		%		0.4		%	1		%
	Dividend yield		—		%		2.2		%	1.4		%
	Weighted-average grant-date fair value per performance share granted		$	4.68			$	9.89		$	15.78
	A summary of the activity for non-vested performance share awards for the year ended December 31, 2013, is presented below:
	Performance Share Awards	Performance Shares			Weighted- Average Grant Date Fair Value
	Outstanding at December 31, 2012	942,313			$	12.24
	Granted	585,450			4.68
	Earned	—			—
	Expired or forfeited	(474,990	)		14.02
	Outstanding at December 31, 2013	1,052,773			7.23
	As of December 31, 2013, there were $3.4 of total unrecognized compensation costs related to non-vested performance share awards granted under the SIP, which costs are expected to be recognized over a weighted-average period of 1.5 years.

Comprehensive_Income_Loss

Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2013
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]	'
Comprehensive Income (Loss)	'
	Comprehensive Income (Loss)
	The details of other comprehensive income (loss), net of tax, are as follows:
			2013
	Foreign currency translation
	Balance at beginning of period		$	3.5
	Other comprehensive income (loss):
	Foreign currency translation gain (loss)		1.2
	Balance at end of period		$	4.7
	Cash flow hedges
	Balance at beginning of period		$	31.7
	Other comprehensive income (loss):
	Gains (losses) arising in period		3.5
	Income tax expense (benefit)		1.3
	Gains (losses) arising in period, net of tax		2.2
	Reclassification of losses (gains) to net income (loss):
	Hot roll carbon steel coil contracts (a)		(0.4		)
	Other commodity contracts (b)		(24.8		)
	Subtotal		(25.2		)
	Income tax (expense) benefit (d)		(9.6		)
	Net amount of reclassification of losses (gains) to net income (loss)		(15.6		)
	Total other comprehensive income (loss), net of tax		(13.4		)
	Balance at end of period		$	18.3
	Unrealized holding gains (losses) on securities
	Balance at beginning of period		$	0.3
	Other comprehensive income (loss):
	Unrealized holding gains (losses) arising in period		0.2
	Income tax expense (benefit)		0.1
	Unrealized holding gains (losses) arising in period, net of tax		0.1
	Balance at end of period		$	0.4
	Pension and OPEB plans
	Balance at beginning of period		$	(34.4	)
	Other comprehensive income (loss):
	Prior service credit (cost) arising in period		(6.1		)
	Gains (losses) arising in period		422.3
	Subtotal		416.2
	Income tax expense (benefit)		50.3
	Gains (losses) arising in period, net of tax		365.9
	Reclassification to net income (loss):
	Prior service costs (credits) (c)		(76.2		)
	Actuarial (gains) losses (c)		25.3
	Subtotal		(50.9		)
	Income tax (expense) benefit (d)		(19.4		)
	Amount of reclassification to net income (loss), net of tax		(31.5		)
	Total other comprehensive income (loss), net of tax		334.4
	Balance at end of period		$	300
	(a)	Amounts are included in net sales on the Consolidated Statements of Operations.
	(b)	Amounts are included in cost of products sold on the Consolidated Statements of Operations.
	(c)	Amounts are included in pension and OPEB expense (income) on the Consolidated Statements of Operations.
	(d)	Amounts are included in income tax expense (benefit) on the Consolidated Statements of Operations.
	The tax effects allocated to each component of other comprehensive income (loss) in 2011 are as follows:
			2011
	Cash flow hedges:
	Gains (losses) arising in period		$	(8.0	)
	Reclassification of loss (gain) to net income (loss)		1.5
	Unrealized holding gain (loss) on securities:
	Unrealized holding gain (loss) arising in period		(0.2		)
	Pension and OPEB plans:
	Prior service cost arising in period		(7.5		)
	Reclassification of prior service cost (credits) included in net income (loss)		(22.3		)
	Gains (losses) arising in period		(122.2		)
	Reclassification of losses (gains) included in net income (loss)		103.9
	Income tax expense (benefit) allocated to other comprehensive income (loss)		$	(54.8	)
	Because of the valuation allowance recorded in 2012, no income tax was allocated to other comprehensive income (loss).

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings per Share
	Reconciliation of the numerators and denominators for basic and diluted EPS computations is as follows:
		2013			2012			2011
	Net income (loss) attributable to AK Steel Holding Corporation	$	(46.8	)	$	(1,027.3	)	$	(155.6	)
	Less: distributed earnings to common stockholders and holders of certain stock compensation awards	—			11			22
	Undistributed earnings (loss)	$	(46.8	)	$	(1,038.3	)	$	(177.6	)
	Common stockholders earnings—basic and diluted:
	Distributed earnings to common stockholders	$	—		$	11		$	22
	Undistributed earnings (loss) to common stockholders	(46.6		)	(1,034.6		)	(176.9		)
	Common stockholders earnings (loss)—basic and diluted	$	(46.6	)	$	(1,023.6	)	$	(154.9	)
	Common shares outstanding (weighted-average shares in millions):
	Common shares outstanding for basic earnings per share	135.8			113			109.8
	Effect of exchangeable debt	—			—			—
	Effect of dilutive stock-based compensation	—			—			—
	Common shares outstanding for diluted earnings per share	135.8			113			109.8
	Basic and diluted earnings per share:
	Distributed earnings	$	—		$	0.1		$	0.2
	Undistributed earnings (loss)	(0.34		)	(9.16		)	(1.61		)
	Basic and diluted earnings (loss) per share	$	(0.34	)	$	(9.06	)	$	(1.41	)
	Potentially issuable common shares (in millions) excluded from earnings per share calculation due to anti-dilutive effect	2.6			2.4			1.2

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2013
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]	'
Variable Interest Entities	'
	Variable Interest Entities
	SunCoke Middletown
	The Company is a party to supply contracts with SunCoke Middletown, an affiliate of SunCoke, to provide the Company with about 550,000 tons of metallurgical-grade lump coke and approximately 45 megawatts of electrical power annually. Under those agreements, the Company will purchase all of SunCoke Middletown’s coke and electrical power through at least 2031. SunCoke Middletown is a variable interest entity. The Company has committed to purchase all of the expected production of SunCoke Middletown and the Company has been determined to be the primary beneficiary. Thus, the financial results of SunCoke Middletown are required to be consolidated with the results of the Company, even though the Company has no ownership interest in SunCoke Middletown. Included in the Consolidated Statements of Operations were income (loss) before taxes related to SunCoke Middletown of $64.3, $46.0 and $(7.8) for the years ended December 31, 2013, 2012 and 2011, respectively.
	Vicksmetal/Armco Associates
	The Company indirectly owns 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 AK Steel, though also for third parties. AK Steel has determined that VAA meets the definition of a variable interest entity and the financial results of VAA are consolidated with the results of the Company, as the primary beneficiary.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The Company measures 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, the Company uses 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 the reporting entity has 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. Common/collective trusts are valued at the net asset value per share multiplied by the number of shares held as of the measurement date. The determination of net asset value for these trusts includes market pricing of the underlying assets as well as broker quotes and other valuation techniques that represent fair value. If the Company has the ability to redeem its investment in the respective alternative investment at the net asset value with no significant restrictions on the redemption at the consolidated balance sheet date, the Company has categorized the alternative investment as a Level 2 measurement in the fair value hierarchy. Fair values of the Company’s commodity derivative contracts and foreign currency forward contracts are generated using forward prices that are derived from observable futures prices relating to the respective commodity or currency from sources such as the New York Mercantile Exchange (NYMEX) or the London Metal Exchange (LME). In cases where the derivative is an option contract (including caps, floors and collars), the Company’s valuations reflect adjustments made to valuations generated by the derivatives’ counterparty. After validating that the counterparty’s assumptions relating to implied volatilities are in line with an independent source for these implied volatilities, the Company discounts these model-generated future values with discount factors designed to reflect the credit quality of the party obligated to pay under the derivative contract. Differing discount rates are applied to different contracts as a function of differing maturities and different counterparties. As of December 31, 2013, a spread over benchmark rates of less than 1.0% was used for derivatives valued as assets and for derivatives valued as liabilities. The Company has 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 the Company for debt of similar terms and maturities.
	•	Level 3 inputs are unobservable inputs for the asset or liability. Unobservable inputs are used to measure fair value to the extent that 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 the Company’s valuations on a normal recurring basis other than for a portion of its pension assets.
	The following fair value table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of the dates indicated:
		2013								2012
		Level 1		Level 2			Total			Level 1		Level 2			Total
	Assets measured at fair value
	Cash and cash equivalents	$	45.3	$	—		$	45.3		$	227	$	—		$	227
	Other current assets—commodity hedge contracts	—		4.9			4.9			—		25.5			25.5
	Other non-current assets:
	Available for sale investments—cash and cash equivalents	18.6		—			18.6			26.3		—			26.3
	Assets measured at fair value	$	63.9	$	4.9		$	68.8		$	253.3	$	25.5		$	278.8
	Liabilities measured at fair value
	Accrued liabilities:
	Foreign exchange contracts	$	—	$	(0.7	)	$	(0.7	)	$	—	$	(0.2	)	$	(0.2	)
	Commodity hedge contracts	—		(0.4		)	(0.4		)	—		(1.3		)	(1.3		)
	Other non-current liabilities—commodity hedge contracts	—		(0.1		)	(0.1		)	—		—			—
	Liabilities measured at fair value	$	—	$	(1.2	)	$	(1.2	)	$	—	$	(1.5	)	$	(1.5	)
	Liabilities measured at other than fair value
	Long-term debt, including current portions:
	Fair value	$	—	$	(1,659.9	)	$	(1,659.9	)	$	—	$	(1,379.3	)	$	(1,379.3	)
	Carrying amount	—		(1,507.0		)	(1,507.0		)	—		(1,411.9		)	(1,411.9		)
	See Note 6 for information on the fair value of pension plan assets. The carrying amounts of the Company’s other financial instruments do not differ materially from their estimated fair values at December 31, 2013 and 2012.

Disclosures_About_Derivative_I

Disclosures About Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Disclosures About Derivative Instruments and Hedging Activities	'
	Disclosures about Derivative Instruments and Hedging Activities
	The Company is subject to fluctuations of exchange rates on a portion of intercompany receivables that are denominated in foreign currencies and uses forward currency contracts to manage exposures to certain of these currency price fluctuations. These contracts have not been designated as hedges for accounting purposes and gains or losses are reported in earnings on a current basis in other income (expense).
	The Company is exposed to fluctuations in market prices of raw materials and energy sources, as well as to the effect of market prices on the sale of certain commodity steel (hot roll carbon steel coils). The Company may use cash-settled commodity price swaps and options (including collars) to hedge the market risk associated with the purchase of certain of its raw materials and energy requirements and the sale of hot roll carbon steel coils. These derivatives are routinely used with respect to a portion of the Company’s natural gas and nickel requirements and are sometimes used with respect to its iron ore, aluminum, zinc and electricity requirements. The Company’s hedging strategy is designed to mitigate the effect on earnings from the price volatility of these various commodity exposures. Independent of any hedging activities, price increases in any of these commodity markets could negatively affect operating costs or selling prices.
	All commodity derivatives are marked to market and recognized as an asset or liability at fair value. The effective gains and losses for commodity derivatives designated as cash flow hedges of forecasted purchases of raw materials and energy sources are recorded in accumulated other comprehensive income (loss) on the Consolidated Balance Sheets and reclassified into cost of products sold in the same period as the earnings recognition of the associated underlying transaction. The effective gains and losses for hot roll carbon steel coils derivatives designated as cash flow hedges of forecasted sales are recorded in accumulated other comprehensive income on the Consolidated Balance Sheets and reclassified into net sales in the same period as the earnings recognition of the associated underlying transaction. Gains and losses on these designated derivatives arising from either hedge ineffectiveness or related to components excluded from the assessment of effectiveness are recognized in current earnings under net sales or cost of products sold, as appropriate. All gains or losses from derivatives for which hedge accounting treatment has not been elected are also reported in earnings on a current basis in net sales or cost of products sold.
	As of December 31, 2013 and 2012, the Company had the following outstanding commodity price swaps and options and forward foreign exchange contracts:
	Commodity		2013			2012
	Nickel (in lbs)		763,300			420,100
	Natural gas (in MMBTUs)		3,240,000			9,000,000
	Zinc (in lbs)		12,000,000			—
	Iron ore (in metric tons)		190,735			1,140,000
	Hot roll carbon steel coils (in short tons)		74,147			30,000
	Foreign exchange contracts (in euros)		€	17,730,000		€	15,950,000
	The following table presents the fair value of derivative instruments in the Consolidated Balance Sheets as of December 31, 2013 and 2012:
	Asset (liability)		2013			2012
	Derivatives designated as hedging instruments:
	Other current assets—commodity contracts		$	2.6		$	25.5
	Accrued liabilities—commodity contracts		—			(1.2		)
	Derivatives not designated as hedging instruments:
	Other current assets—commodity contracts		2.3			—
	Accrued liabilities:
	Foreign exchange contracts		(0.7		)	(0.2		)
	Commodity contracts		(0.4		)	(0.1		)
	Other noncurrent liabilities—commodity contracts		(0.1		)	—
	The following table presents gains (losses) on derivative instruments included in the Consolidated Statements of Operations for the years ended December 31, 2013, 2012 and 2011:
	Gain (loss)		2013			2012			2011
	Derivatives in cash flow hedging relationships—
	Commodity contracts:
	Reclassified from accumulated other comprehensive income into net sales (effective portion)		$	0.4		$	—		$	—
	Reclassified from accumulated other comprehensive income into cost of products sold (effective portion)		24.8			(36.3		)	(4.0		)
	Recorded in cost of products sold (ineffective portion and amount excluded from effectiveness testing)		3.3			0.1			(10.2		)
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts—recognized in other income (expense)		(0.1		)	(1.2		)	0.8
	Commodity contracts:
	Recognized in net sales		(3.1		)	—			—
	Recognized in cost of products sold		1.7			(0.6		)	(5.1		)
	The following table lists the amount of gains (losses) before tax expected to be reclassified into earnings within the next twelve months for the Company’s existing commodity contracts that qualify for hedge accounting, as well as the period of time over which the Company is hedging its exposure to the volatility in future cash flows:
	Commodity Hedge	Settlement Dates		Gains (losses)
	Natural gas	January 2014 to December 2014		$	2.3
	Zinc	January 2014 to December 2014		0.5

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]	'
Supplemental Cash Flow Information	'
	Supplemental Cash Flow Information
	The following table presents the net cash paid (received) during the period for interest, net of capitalized interest, and income taxes:
		2013		2012		2011
	Net cash paid (received) during the period for:
	Interest, net of capitalized interest	$	116.2	$	69.5	$	44.3
	Income taxes	1.2		1.3		0.1
	Included in net cash flows from operations was cash provided by (used by) SunCoke Middletown of $82.6, $55.2 and $(15.7) for the years ended December 31, 2013, 2012 and 2011, respectively. Consolidated cash and cash equivalents at December 31, 2013, includes $14.2 of cash and cash equivalents of SunCoke Middletown. There are no compensating balance arrangements or legal restrictions on the cash and cash equivalents of SunCoke Middletown, however, it is not available for the Company’s use.
	The Company had non-cash capital investments during the years ended December 31, 2013, 2012 and 2011, 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 Consolidated Statements of Cash Flows. The Company also granted restricted stock to certain employees and restricted stock units to directors under the SIP. The amounts of non-cash investing and financing activities for the years ended December 31, 2013, 2012 and 2011, were as follows:
		2013		2012		2011
	Capital investments	$	10.2	$	13.9	$	10.2
	Capital investments—SunCoke Middletown	—		—		16.3
	Issuance of restricted stock and restricted stock units	3		5.4		5.7
	Issuance of note payable for AK Coal purchase (at fair value)	—		—		10.2

Consolidated_Quarterly_Sales_a

Consolidated Quarterly Sales and Earning (Losses)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Information (Unaudited)	'
	Quarterly Information (Unaudited)
	Earnings per share for each quarter and the year are calculated individually and may not sum to the total for the year.
		2013
		First			Second			Third			Fourth			Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	1,369.80		$	1,404.50		$	1,331.30		$	1,464.80		$	5,570.40
	Operating profit	33.2			13.7			25.9			63			135.8
	Net income (loss) attributable to AK Holding	(9.9		)	(40.4		)	(31.7		)	35.2			(46.8		)
	Basic and diluted earnings (loss) per share	$	(0.07	)	$	(0.30	)	$	(0.23	)	$	0.26		$	(0.34	)
		2012
		First			Second			Third			Fourth			Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	1,508.70		$	1,538.40		$	1,463.50		$	1,423.10		$	5,933.70
	Operating profit (loss)	4.1			56.7			(12.0		)	(176.9		)	(128.1		)
	Net income (loss) attributable to AK Holding	(11.8		)	(724.2		)	(60.9		)	(230.4		)	(1,027.3		)
	Basic and diluted earnings (loss) per share	$	(0.11	)	$	(6.55	)	$	(0.55	)	$	(1.89	)	$	(9.06	)
	Included in operating profit (loss) for the fourth quarter and full year of 2012 was a pension corridor charges of $157.3. Included in net income (loss) attributable to AK Holding for the second quarter of 2012 was a charge to income tax expense of $736.0 for an increase in the valuation allowance on its deferred tax assets. Income taxes for the second and third quarters of 2013 were estimated using the discrete method.

Supplemental_Guarantor_Informa

Supplemental Guarantor Information	12 Months Ended
	Dec. 31, 2013
Supplemental Guarantor Information [Abstract]	'
Supplemental Guarantor Information	'
	Supplemental Guarantor Information
	AK Steel’s Secured Notes, 2020 Notes, 2022 Notes and Exchangeable Notes (the “Senior Notes”) are governed by indentures entered into by AK Holding and its 100% owned subsidiary, AK Steel. Under the terms of the indentures, AK Holding fully and unconditionally, jointly and severally, guarantees the payment of interest, principal and premium, if any, on each of the notes comprising the Senior Notes. AK Holding is the sole guarantor of the Senior Notes.
	The presentation of the supplemental guarantor information reflects all investments in subsidiaries under the equity method of accounting. Net income (loss) of the subsidiaries accounted for under the equity method is therefore reflected in their parents’ investment accounts. The principal elimination entries eliminate investments in subsidiaries and inter-company balances and transactions. The following supplemental condensed consolidating financial statements present information about AK Holding, AK Steel and the other non-guarantor subsidiaries.
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2013
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	5,339.30		$	830.3		$	(599.2	)	$	5,570.40
	Cost of products sold (exclusive of items shown separately below)	—			5,012.10			652.3			(556.6		)	5,107.80
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			205			36.7			(40.8		)	205.3
	Depreciation	—			169.4			20.7			—			190.1
	Pension and OPEB expense (income)	—			(68.6		)	—			—			(68.6		)
	Total operating costs	4.4			5,317.90			709.7			(597.4		)	5,434.60
	Operating profit (loss)	(4.4		)	21.4			120.6			(1.8		)	135.8
	Interest expense	—			125.9			1.5			—			127.4
	Other income (expense)	—			(5.9		)	4.5			—			(1.4		)
	Income (loss) before income taxes	(4.4		)	(110.4		)	123.6			(1.8		)	7
	Income tax expense (benefit)	—			(27.8		)	18.1			(0.7		)	(10.4		)
	Equity in net income (loss) of subsidiaries	(42.4		)	40.2			—			2.2			—
	Net income (loss)	(46.8		)	(42.4		)	105.5			1.1			17.4
	Less: Net income (loss) attributable to noncontrolling interests	—			—			64.2			—			64.2
	Net income (loss) attributable to AK Steel Holding Corporation	(46.8		)	(42.4		)	41.3			1.1			(46.8		)
	Other comprehensive income (loss)	322.3			322.3			1.2			(323.5		)	322.3
	Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	275.5		$	279.9		$	42.5		$	(322.4	)	$	275.5
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2012
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	5,676.60		$	906.3		$	(649.2	)	$	5,933.70
	Cost of products sold (exclusive of items shown separately below)	—			5,416.80			738			(615.7		)	5,539.10
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			212.9			35.3			(43.9		)	208.7
	Depreciation	—			172.8			19.2			—			192
	Pension and OPEB expense (income) (exclusive of corridor charge shown below)	—			(35.3		)	—			—			(35.3		)
	Pension corridor charge	—			157.3			—			—			157.3
	Total operating costs	4.4			5,924.50			792.5			(659.6		)	6,061.80
	Operating profit (loss)	(4.4		)	(247.9		)	113.8			10.4			(128.1		)
	Interest expense	—			85.9			0.8			—			86.7
	Other income (expense)	—			(9.6		)	15.8			—			6.2
	Income (loss) before income taxes	(4.4		)	(343.4		)	128.8			10.4			(208.6		)
	Income tax expense (benefit)	—			735.9			49.9			4.2			790
	Equity in net income (loss) of subsidiaries	(1,022.9		)	56.4			—			966.5			—
	Net income (loss)	(1,027.3		)	(1,022.9		)	78.9			972.7			(998.6		)
	Less: Net income (loss) attributable to noncontrolling interests	—			—			28.7			—			28.7
	Net income (loss) attributable to AK Steel Holding Corporation	(1,027.3		)	(1,022.9		)	50.2			972.7			(1,027.3		)
	Other comprehensive income (loss)	(1.6		)	(1.6		)	0.7			0.9			(1.6		)
	Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	(1,028.9	)	$	(1,024.5	)	$	50.9		$	973.6		$	(1,028.9	)
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2011
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	6,205.90		$	756.7		$	(494.6	)	$	6,468.00
	Cost of products sold (exclusive of items shown separately below)	—			5,854.10			635.1			(452.4		)	6,036.80
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			222.3			36.4			(47.7		)	215.4
	Depreciation	—			177.4			7.6			—			185
	Pension and OPEB expense (income) (exclusive of corridor charge shown below)	—			(36.0		)	—			—			(36.0		)
	Pension corridor charge	—			268.1			—			—			268.1
	Total operating costs	4.4			6,485.90			679.1			(500.1		)	6,669.30
	Operating profit (loss)	(4.4		)	(280.0		)	77.6			5.5			(201.3		)
	Interest expense	—			47.3			0.2			—			47.5
	Other income (expense)	—			(8.4		)	3.1			—			(5.3		)
	Income (loss) before income taxes	(4.4		)	(335.7		)	80.5			5.5			(254.1		)
	Income tax expense (benefit)	(1.8		)	(125.6		)	31.2			2.2			(94.0		)
	Equity in net income (loss) of subsidiaries	(153.0		)	57.1			—			95.9			—
Net income (loss)	(155.6		)	(153.0		)	49.3			99.2			(160.1		)
Less: Net income (loss) attributable to noncontrolling interests	—			—			(4.5		)	—			(4.5		)
Net income (loss) attributable to AK Steel Holding Corporation	(155.6		)	(153.0		)	53.8			99.2			(155.6		)
Other comprehensive income (loss)	(89.9		)	(89.9		)	(0.7		)	90.6			(89.9		)
Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	(245.5	)	$	(242.9	)	$	53.1		$	189.8		$	(245.5	)
Condensed Balance Sheets
December 31, 2013
	AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
	Holding			Steel
ASSETS
Current assets:
Cash and cash equivalents	$	—		$	16.8		$	28.5		$	—		$	45.3
Accounts receivable, net	—			492.4			61.1			(28.3		)	525.2
Inventory, net	—			520			77.7			(11.1		)	586.6
Deferred tax assets, current	—			69.4			0.2			—			69.6
Other current assets	0.3			43.9			2.3			—			46.5
Total current assets	0.3			1,142.50			169.8			(39.4		)	1,273.20
Property, plant and equipment	—			5,258.40			613.5			—			5,871.90
Accumulated depreciation	—			(3,881.7		)	(110.1		)	—			(3,991.8		)
Property, plant and equipment, net	—			1,376.70			503.4			—			1,880.10
Other non-current assets:
Investment in Magnetation LLC	—			—			187.8			—			187.8
Investment in affiliates	(2,772.4		)	1,393.80			—			1,378.60			—
Inter-company accounts	2,551.10			(3,479.7		)	896.7			31.9			—
Other non-current assets	—			141			123.6			—			264.6
TOTAL ASSETS	$	(221.0	)	$	574.3		$	1,881.30		$	1,371.10		$	3,605.70
LIABILITIES AND EQUITY (DEFICIT)
Current liabilities:
Accounts payable	$	—		$	550.5		$	51.9		$	(0.6	)	$	601.8
Accrued liabilities	—			133.6			9.3			—			142.9
Current portion of long-term debt	—			0.8			—			—			0.8
Current portion of pension and other postretirement benefit obligations	—			85.4			0.5			—			85.9
Total current liabilities	—			770.3			61.7			(0.6		)	831.4
Non-current liabilities:
Long-term debt	—			1,506.20			—			—			1,506.20
Pension and other postretirement benefit obligations	—			960.6			4.8			—			965.4
Other non-current liabilities	—			109.6			0.4			—			110
TOTAL LIABILITIES	—			3,346.70			66.9			(0.6		)	3,413.00
Total stockholders’ equity (deficit)	(221.0		)	(2,772.4		)	1,400.70			1,371.70			(221.0		)
Noncontrolling interests	—			—			413.7			—			413.7
TOTAL EQUITY (DEFICIT)	(221.0		)	(2,772.4		)	1,814.40			1,371.70			192.7
TOTAL LIABILITIES AND EQUITY (DEFICIT)	$	(221.0	)	$	574.3		$	1,881.30		$	1,371.10		$	3,605.70
Condensed Balance Sheets
December 31, 2012
	AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
	Holding			Steel
ASSETS
Current assets:
Cash and cash equivalents	$	—		$	203.6		$	23.4		$	—		$	227
Accounts receivable, net	—			484.4			54.3			(64.8		)	473.9
Inventory, net	—			504.2			114.4			(9.4		)	609.2
Deferred tax assets, current	—			73			0.2			—			73.2
Other current assets	0.2			57.6			1.6			—			59.4
Total current assets	0.2			1,322.80			193.9			(74.2		)	1,442.70
Property, plant and equipment	—			5,355.10			588.8			—			5,943.90
Accumulated depreciation	—			(3,841.9		)	(89.7		)	—			(3,931.6		)
Property, plant and equipment, net	—			1,513.20			499.1			—			2,012.30
Other non-current assets:
Investment in Magnetation LLC	—			—			150			—			150
Investment in affiliates	(2,660.7		)	1,337.40			—			1,323.30			—
Inter-company accounts	2,155.20			(3,066.5		)	843.8			67.5			—
Other non-current assets	—			167.7			130.4			—			298.1
TOTAL ASSETS	$	(505.3	)	$	1,274.60		$	1,817.20		$	1,316.60		$	3,903.10
LIABILITIES AND EQUITY (DEFICIT)
Current liabilities:
Accounts payable	$	—		$	494.8		$	44.4		$	(0.9	)	$	538.3
Accrued liabilities	—			155			9.8			—			164.8
Current portion of long-term debt	—			0.7			—			—			0.7
Current portion of pension and other postretirement benefit obligations	—			108.1			0.5			—			108.6
Total current liabilities	—			758.6			54.7			(0.9		)	812.4
Non-current liabilities:
Long-term debt	—			1,411.20			—			—			1,411.20
Pension and other postretirement benefit obligations	—			1,657.20			4.5			—			1,661.70
Other non-current liabilities	—			108.3			0.5			—			108.8
TOTAL LIABILITIES	—			3,935.30			59.7			(0.9		)	3,994.10
Total stockholders’ equity (deficit)	(505.3		)	(2,660.7		)	1,343.20			1,317.50			(505.3		)
Noncontrolling interests	—			—			414.3			—			414.3
TOTAL EQUITY (DEFICIT)	(505.3		)	(2,660.7		)	1,757.50			1,317.50			(91.0		)
TOTAL LIABILITIES AND EQUITY (DEFICIT)	$	(505.3	)	$	1,274.60		$	1,817.20		$	1,316.60		$	3,903.10
Condensed Statements of Cash Flows
Year Ended December 31, 2013
	AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
	Holding			Steel
Net cash flows from operating activities	$	(3.5	)	$	(251.1	)	$	180		$	(35.6	)	$	(110.2	)
Cash flows from investing activities:
Capital investments	—			(39.2		)	(24.4		)	—			(63.6		)
Investments in acquired businesses	—			—			(50.0		)	—			(50.0		)
Other investing items, net	—			8.5			6.6			—			15.1
Net cash flows from investing activities	—			(30.7		)	(67.8		)	—			(98.5		)
Cash flows from financing activities:
Net borrowings (repayments) under credit facility	—			90			—			—			90
Proceeds from issuance of long-term debt	—			31.9			—			—			31.9
Redemption of long-term debt	—			(27.4		)	—			—			(27.4		)
Debt issuance costs	—			(3.4		)	—			—			(3.4		)
Inter-company activity	4.1			3.9			(43.6		)	35.6			—
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			(64.8		)	—			(64.8		)
Other financing items, net	(0.6		)	—			1.3			—			0.7
Net cash flows from financing activities	3.5			95			(107.1		)	35.6			27
Net increase (decrease) in cash and cash equivalents	—			(186.8		)	5.1			—			(181.7		)
Cash and equivalents, beginning of year	—			203.6			23.4			—			227
Cash and equivalents, end of year	$	—		$	16.8		$	28.5		$	—		$	45.3
Condensed Statements of Cash Flows
Year Ended December 31, 2012
	AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
	Holding			Steel
Net cash flows from operating activities	$	(3.5	)	$	(360.0	)	$	113.1		$	(20.4	)	$	(270.8	)
Cash flows from investing activities:
Capital investments	—			(38.3		)	(25.8		)	—			(64.1		)
Investments in acquired businesses	—			—			(60.6		)	—			(60.6		)
Other investing items, net	—			6.7			(0.6		)	—			6.1
Net cash flows from investing activities	—			(31.6		)	(87.0		)	—			(118.6		)
Cash flows from financing activities:
Net borrowings (repayments) under credit facility	—			(250.0		)	—			—			(250.0		)
Proceeds from issuance of long-term debt	—			873.3			—			—			873.3
Redemption of long-term debt	—			(74.0		)	—			—			(74.0		)
Proceeds from issuance of common stock	96.4			—			—			—			96.4
Debt issuance costs	—			(22.3		)	—			—			(22.3		)
Common stock dividends paid	(11.0		)	—			—			—			(11.0		)
Inter-company activity	(80.2		)	48.8			11			20.4			—
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			(36.6		)	—			(36.6		)
Other financing items, net	(1.7		)	(0.5		)	0.8			—			(1.4		)
Net cash flows from financing activities	3.5			575.3			(24.8		)	20.4			574.4
Net increase (decrease) in cash and cash equivalents	—			183.7			1.3			—			185
Cash and equivalents, beginning of year	—			19.9			22.1			—			42
Cash and equivalents, end of year	$	—		$	203.6		$	23.4		$	—		$	227
Condensed Statements of Cash Flows
Year Ended December 31, 2011
	AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
	Holding			Steel
Net cash flows from operating activities	$	(1.7	)	$	(216.9	)	$	39.7		$	(1.6	)	$	(180.5	)
Cash flows from investing activities:
Capital investments	—			(98.9		)	(197.2		)	—			(296.1		)
Investments in acquired businesses	—			—			(125.4		)	—			(125.4		)
Other investing items, net	—			1.4			(0.1		)	—			1.3
Net cash flows from investing activities	—			(97.5		)	(322.7		)	—			(420.2		)
Cash flows from financing activities:
Net borrowings (repayments) under credit facility	—			250			—			—			250
Redemption of long-term debt	—			(0.7		)	—			—			(0.7		)
Debt issuance costs	—			(10.1		)	—			—			(10.1		)
Common stock dividends paid	(22.0		)	—			—			—			(22.0		)
Inter-company activity	25			(106.4		)	79.8			1.6			—
SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			210.7			—			210.7
Other financing items, net	(1.3		)	0.1			(0.8		)	—			(2.0		)
Net cash flows from financing activities	1.7			132.9			289.7			1.6			425.9
Net increase (decrease) in cash and cash equivalents	—			(181.5		)	6.7			—			(174.8		)
Cash and equivalents, beginning of year	—			201.4			15.4			—			216.8
Cash and equivalents, end of year	$	—		$	19.9		$	22.1		$	—		$	42

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Basis of Presentation	'
	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,” and together with AK Holding, the “Company”), all subsidiaries in which the Company has a controlling interest, and two variable interest entities for which the Company is the primary beneficiary.  The Company also operates European trading companies that buy and sell steel and steel products and other materials. The Company manages its operations on a consolidated, integrated basis in order to utilize the most appropriate equipment and facilities for the production of a product, regardless of product line, and concludes that it operates in a single business segment. All intercompany transactions and balances have been eliminated.
Use of Estimates	'
	Use of Estimates: The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires the use of estimates and assumptions that affect the amounts reported.  These estimates are based on historical experience and information that is available to management about current events and actions the Company may take in the future.  Significant items subject to estimates and assumptions include the carrying value of long-lived assets, including goodwill; valuation allowances for receivables, inventories and deferred income tax assets; legal and environmental liabilities; workers compensation and asbestos liabilities; share-based compensation; investment in AFSG Holdings, Inc.; excess cost of operations; and assets and obligations related to employee benefit plans.  There can be no assurance that actual results will not differ from these estimates.
Revenue Recognition	'
	Revenue Recognition: Revenue from sales of products is recognized at the time that title and the risks and rewards of ownership pass, which can be on the date of shipment or the date of receipt by the customer depending on when the terms of customers’ arrangements are met, the sales price is fixed or determinable, and collection is reasonably assured.
Revenue Recognition, Excise And Sales Taxes	'
	Revenue is not recognized for sales taxes collected from customers; rather these taxes are recorded on a net basis in the Consolidated Statements of Operations.
Cost of Products Sold	'
	Cost of Products Sold: Cost of products sold consists primarily of raw materials, energy costs, supplies consumed in the manufacturing process, manufacturing labor, contract labor and direct overhead expense necessary to manufacture the finished steel product, as well as distribution and warehousing costs.
Cost of Products Sold, Equity Method Investments	'
	The Company’s share of the income (loss) of investments in associated companies accounted for under the equity method are included in costs of products sold since these operations are integrated with the Company’s overall steelmaking operations, except for its share of the income (loss) of Magnetation LLC that is included in other income (expense).
Share-Based Compensation	'
	Share-Based Compensation: Compensation costs related to all stock awards granted under the Company’s Stock Incentive Plan are charged against operations during their vesting period using the straight-line method.
Legal Fees	'
	Legal Fees: Legal fees associated with litigation and similar proceedings that are not expected to provide a benefit in future periods are generally expensed as incurred. Legal fees associated with activities that are expected to provide a benefit in future periods, such as costs associated with the issuance of debt, are generally capitalized as incurred in the Consolidated Balance Sheets.
Income Taxes	'
	Income Taxes: The Company records interest and penalties related to uncertain tax positions as a component of income tax expense. Deferred tax assets do not include certain amounts that arise from tax deductions related to share-based compensation in excess of compensation recognized for financial reporting when net operating loss carryforwards are created.  The Company uses tax law ordering for purposes of determining when excess tax benefits have been realized.
Earnings per Share	'
	Earnings per Share: Earnings per share is calculated using the “two-class” method. Under the “two-class” method, undistributed earnings are allocated to both common shares and participating securities. The sum of distributed earnings to common stockholders and undistributed earnings allocated to common stockholders is divided by the weighted-average number of common shares outstanding during the period. The restricted stock granted by AK Holding is entitled to dividends prior to vesting and meets the criteria of a participating security.
Cash Equivalents	'
	Cash Equivalents: Cash equivalents include short-term, highly-liquid investments that are readily convertible to known amounts of cash and are of an original maturity of three months or less.
Inventories	'
	Inventories: Inventories are valued at the lower of cost or market. The cost of the majority of inventories is measured on the last-in, first-out (LIFO) method. Other inventories are measured principally at average cost and consist mostly of foreign inventories and certain raw materials.
Property, Plant and Equipment	'
	Property, Plant and Equipment: Plant and equipment are depreciated under the straight-line method over their estimated lives.  Estimated lives are as follows: land improvements over 20 years, leaseholds over the life of the lease, buildings over 40 years and machinery and equipment over 2 to 20 years.  The estimated weighted-average life of the Company’s machinery and equipment is 19.1 years at the end of the current year.  Costs incurred to develop coal mines are capitalized. Depletion of coal reserves and mine development costs are computed using the units-of-production method utilizing only proven and probable reserves in the depletion base.
Property, Plant and Equipment, Planned Major Maintenance Activities	'
	The Company expenses costs associated with major maintenance activities at its operating facilities in the period in which they occur.
Property, Plant and Equipment, Impairment or Disposal of Long-Lived Assets	'
	The Company reviews the carrying value of long-lived assets to be held and used and long-lived assets to be disposed of when events and circumstances warrant such a review.  If the carrying value of a long-lived asset exceeds its fair value an impairment has occurred and a loss is recognized based on the amount by which the carrying value exceeds the fair value, less cost to dispose, for assets to be sold or abandoned.  Fair value is determined using quoted market prices, estimates based on prices of similar assets or anticipated cash flows discounted at a rate commensurate with risk.
Investments	'
	Investments: The Company has investments in associated companies that are accounted for under the equity method.  Each of these investments is subject to a review for impairment when circumstances indicate that a loss in value below its carrying amount is other than temporary.  No impairment was recorded in 2013, 2012 or 2011.
	The Company’s investment in AFSG Holdings, Inc., an indirect wholly-owned subsidiary of the Company, represents the carrying value of its discontinued insurance and finance leasing businesses, which have been largely liquidated.  The activities of the remaining operating companies are being “run off” and the companies are accounted for as a discontinued operation.  The Company is under no obligation to support the operations or liabilities of these companies.
Goodwill	'
	Goodwill: Goodwill relates primarily to the Company’s tubular business. Goodwill is reviewed for potential impairment at least annually on October 1 each year and whenever events or circumstances make it more likely than not that impairment may have occurred.  Considering operating results and the estimated fair value of the business, the most recent annual goodwill impairment test indicated that the fair value of the Company’s reporting unit with goodwill was in excess of its carrying value. No goodwill impairment was recorded as a result of the 2013, 2012 and 2011 annual reviews.
Pension and Other Postretirement Benefits	'
	Pension and Other Postretirement Benefits: The Company recognizes in operations, as of the measurement date, any unrecognized actuarial net gains or losses that exceed 10% of the larger of the projected benefit obligations or the plan assets, defined as the “corridor”.  Amounts inside the corridor are amortized over the plan participants’ life expectancy. The Company determines the expected return on assets using the fair value of plan assets.
Concentrations of Credit Risk	'
	Concentrations of Credit Risk: The Company is primarily a producer of carbon, stainless and electrical steels and steel products, which are sold to a number of markets, including automotive, industrial machinery and equipment, construction, power distribution and appliances.  The following presents net sales by product line:
		2013			2012				2011
	Stainless and electrical	$	1,705.30		$	1,898.90			$	2,188.90
	Carbon	3,643.40			3,789.60				4,009.50
	Tubular	220.7			243.6				247.7
	Other	1			1.6				21.9
	Total	$	5,570.40		$	5,933.70			$	6,468.00
	The following sets forth the percentage of the Company’s net sales attributable to various markets:
		2013		2012			2011
	Automotive	51	%	45	%		36	%
	Infrastructure and Manufacturing	20	%	23	%		24	%
	Distributors and Converters	29	%	32	%		40	%
	The Company sells domestically to customers 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 totaled $708.0, $856.7 and $946.4 for 2013, 2012 and 2011, respectively. No customer accounted for more than 10% of net sales of the Company during 2013, 2012 and 2011.
Concentrations of Credit Risk, Trade Accounts Receivable	'
	Approximately 41% and 43% of accounts receivable outstanding at December 31, 2013 and 2012, respectively, are due from businesses associated with the U.S. automotive industry.  Except in a few situations where the risk warrants it, collateral is not required on accounts receivable.  While the Company believes its recorded accounts receivable will be collected, in the event of default the Company would follow normal collection procedures. The Company maintains an allowance for doubtful accounts for the loss that would be incurred if a customer is unable to pay amounts due to the Company.  The Company determines this allowance based on various factors, including the customer’s financial condition and changes in customer payment patterns. The Company writes off accounts receivable against the allowance for doubtful accounts when it is remote that collection will occur.
Union Contracts	'
	Union Contracts: At December 31, 2013, the Company employed approximately 6,400 employees, of which approximately 4,700 are represented by labor unions under various contracts that expire between 2014 and 2017.  An agreement with the United Steelworkers, Local 169, which represents approximately 280 employees at the Company’s Mansfield Works, is scheduled to expire on March 31, 2014. An agreement with the International Association of Machinists and Aerospace Workers, Local 1943, which represents approximately 1,650 employees at the Company’s Middletown Works, is scheduled to expire on September 15, 2014.
Financial Instruments, Marketable Securities	'
	Financial Instruments: Investments in debt securities are classified as held-to-maturity because the Company has the positive intent and ability to hold the securities to maturity.  Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity.  Investments in equity securities are classified as available-for-sale.  Available-for-sale securities are carried at fair value, with unrealized gains and losses, net of tax, reported in other comprehensive income.  Realized gains and losses on sales of available-for-sale securities are computed based upon initial cost adjusted for any other than temporary declines in fair value.  The Company has no investments that are considered to be trading securities. Debt and equity securities are subject to a review for impairment when circumstances indicate that a loss in value is other than temporary.
Financial Instruments, Derivatives	'
	The Company is a party to derivative instruments that are designated and qualify as hedges for accounting purposes.  The Company may also enter into derivative instruments to which it does not apply hedge accounting treatment.  The Company’s objective in using these instruments is to protect its earnings and cash flows from fluctuations in the fair value of selected commodities and currencies.
	The Company’s income and cash flows may be affected by fluctuations in the price of certain commodities used in its production processes and in the selling price of certain commodity steel (hot roll carbon steel coils).  The Company has implemented raw material and energy surcharges for its spot market customers and some of its contract customers.  For certain commodities where such exposure exists, the Company may use cash-settled commodity price swaps, collars and purchase options, with a duration of up to three years, to hedge the price of a portion of its natural gas, iron ore, electricity, aluminum, zinc and nickel requirements or the selling price of hot roll carbon steel coils.  The Company may designate some of these instruments as cash flow hedges and the effective portion of the changes in their fair value and settlements are recorded in accumulated other comprehensive income.  Gains and losses are subsequently reclassified from accumulated other comprehensive income and recorded in cost of products sold or net sales in the same period as the earnings recognition of the associated underlying transaction.  Other instruments are marked to market and recorded in cost of products sold or net sales with the offset recorded as current assets or accrued liabilities.
	In addition, the Company is subject to risks associated with exchange rate fluctuations on monies received from its European subsidiaries and other customers invoiced in European currencies.  In order to mitigate this risk, the Company has entered into a series of agreements for the forward sale of euros at fixed dollar rates.  The forward contracts are entered into with durations of up to eighteen months.  A typical contract is used as a cash flow hedge for the period from when an order is taken to when a sale is recognized, at which time it converts into a fair value hedge of a euro-denominated receivable.  The Company does not classify these derivatives as hedges for accounting purposes and the hedges are marked to market on a quarterly basis with the expense or income recognized in other income (expense).
	The Company formally documents all relationships between hedging instruments and hedged items, as well as its risk management objectives and strategies for undertaking various hedge transactions.  In this documentation, the Company specifically identifies the asset, liability, firm commitment or forecasted transaction that has been designated as a hedged item, and states how the hedging instrument is expected to hedge the risks related to that item.  The Company formally measures effectiveness of its hedging relationships both at the hedge inception and on an ongoing basis.  The Company discontinues hedge accounting prospectively when it determines that the derivative is no longer effective in offsetting changes in the fair value or cash flows of a hedged item; when the derivative expires or is sold, terminated or exercised; when it is probable that the forecasted transaction will not occur; when a hedged firm commitment no longer meets the definition of a firm commitment; or when the Company determines that designation of the derivative as a hedge instrument is no longer appropriate.
Asbestos and Environmental Reserves	'
	Asbestos and Environmental Accruals: The Company is, and has been for a number of years, in the process of remediating sites where hazardous material may have been released, including sites no longer owned by the Company.  In addition, a number of lawsuits alleging asbestos exposure have been filed and continue to be filed against the Company.  The Company has established accruals for estimated probable costs related to asbestos claim settlements and environmental investigation, monitoring and remediation.  If the accruals are not adequate to meet future claims, operating results and cash flows may be negatively affected.  The accruals do not consider the potential for insurance recoveries, for which the Company has partial insurance coverage for some future asbestos claims.  In addition, some existing insurance policies covering asbestos and environmental contingencies may serve to partially mitigate future covered expenditures.
New Accounting Pronouncements	'
	New Accounting Pronouncements: No new accounting pronouncement issued or effective during the 2013 fiscal year has had or is expected to have a material effect on the Company’s consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Revenue from External Customers by Product Line	'
	The following presents net sales by product line:
		2013			2012				2011
	Stainless and electrical	$	1,705.30		$	1,898.90			$	2,188.90
	Carbon	3,643.40			3,789.60				4,009.50
	Tubular	220.7			243.6				247.7
	Other	1			1.6				21.9
	Total	$	5,570.40		$	5,933.70			$	6,468.00
Schedule of Percentage of Net Sales by Market	'
	The following sets forth the percentage of the Company’s net sales attributable to various markets:
		2013		2012			2011
	Automotive	51	%	45	%		36	%
	Infrastructure and Manufacturing	20	%	23	%		24	%
	Distributors and Converters	29	%	32	%		40	%

Supplementary_Financial_Statem1

Supplementary Financial Statement Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplementary Financial Statement Information [Abstract]	'
Allowance for doubtful accounts	'
	The following shows changes in the allowance for doubtful accounts for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	9.1		$	11.9		$	13.1
	Increase (decrease) in allowance	(0.4		)	(2.7		)	(1.1		)
	Receivables written off	(0.6		)	(0.1		)	(0.1		)
	Balance at end of year	$	8.1		$	9.1		$	11.9
Inventory, net	'
	Inventories as of December 31, 2013 and 2012, consist of:
		2013			2012
	Finished and semi-finished	$	722.2		$	728.5
	Raw materials	260.9			315.7
	Total cost	983.1			1,044.20
	Adjustment to state inventories at LIFO value	(396.5		)	(435.0		)
	Inventory, net	$	586.6		$	609.2
Change in LIFO reserve	'
	The following shows changes in the LIFO reserve for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	435		$	524		$	514.2
	Change in reserve	(38.5		)	(89.0		)	9.8
	Balance at end of year	$	396.5		$	435		$	524
Property, plant and equipment	'
	The Company’s property, plant and equipment balances as of December 31, 2013 and 2012 are as follows:
		2013			2012
	Land, land improvements and leaseholds	$	249.5		$	239.8
	Buildings	403.7			428.3
	Machinery and equipment	5,178.00			5,224.40
	Construction in progress	40.7			51.4
	Total	5,871.90			5,943.90
	Less accumulated depreciation	(3,991.8		)	(3,931.6		)
	Property, plant and equipment, net	$	1,880.10		$	2,012.30
Other non-current assets	'
	Other non-current assets as of December 31, 2013 and 2012, consist of:
		2013			2012
	Investment in AFSG Holdings, Inc.	$	55.6		$	55.6
	Goodwill	37.1			37.1
	Deferred tax assets, non-current	76.6			88.2
	Other	95.3			117.2
	Other non-current assets	$	264.6		$	298.1

Investments_in_Equity_Investee1

Investments in Equity Investees (Tables)	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Equity Method Investments [Table Text Block]	'
	Summarized financial statement data for all investees is presented below. The Company is required to report this information for 2013 as a result of the comparative results of the investees to the Company. Although not previously required, prior period amounts have been disclosed for comparison.
			2013			2012			2011
	Revenue		$	293.9		$	297.9		$	237.5
	Gross profit		103.7			92.6			63.2
	Net income		20.1			40.8			20.2
			2013			2012
	Current assets		$	279.9		$	97.8
	Noncurrent assets		440.4			205.5
	Current liabilities		58.5			23.9
	Noncurrent liabilities		397.4			52.2
Schedule of Related Party Transactions [Table Text Block]	'
	The following relates to the Company’s transactions with these equity investees for the years indicated:
		2013			2012			2011
	Sales to equity investees	$	71.6		$	60.4		$	52.8
	Purchases from equity investees	12.5			11.8			12.4
	The following is the Company’s outstanding receivables and payables with the above equity investees as of the end of the year indicated:
		2013			2012
	Accounts receivable from equity investees	$	4		$	2.3
	Accounts payable to equity investees	0.9			1.1
	Notes receivable from equity investees	—			7.6

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Income before Income Tax, Domestic and Foreign	'
	Components of income (loss) before income taxes are as follows:
		2013			2012			2011
	United States	$	(61.1	)	$	(261.2	)	$	(252.5	)
	Foreign	3.9			6.3			5.7
	Noncontrolling interests	64.2			46.3			(7.3		)
	Income (loss) before income taxes	$	7		$	(208.6	)	$	(254.1	)
Schedule of Deferred Tax Assets and Liabilities	'
	Significant components of the Company’s deferred tax assets and liabilities at December 31, 2013 and 2012 are as follows:
		2013			2012
	Deferred tax assets:
	Net operating loss and tax credit carryforwards	$	663.5		$	625
	Postretirement benefits	185			231.6
	Pension benefits	216.6			374
	Inventories	118.8			116.7
	Other assets	96.3			94.4
	Valuation allowance	(764.1		)	(873.1		)
	Total deferred tax assets	516.1			568.6
	Deferred tax liabilities:
	Depreciable assets	(333.1		)	(357.7		)
	Other liabilities	(36.8		)	(49.5		)
	Total deferred tax liabilities	(369.9		)	(407.2		)
	Net deferred tax assets	$	146.2		$	161.4
Summary of Valuation Allowance	'
	The following reflects changes in the valuation allowance for the years ended December 31, 2013, 2012 and 2011:
		2013			2012			2011
	Balance at beginning of year	$	873.1		$	22.3		$	21.6
	Change in valuation allowance:
	Included in income tax expense (benefit)	21.9			865.5			0.7
	Change in deferred assets related to other comprehensive income	(130.9		)	—			—
	Included in stockholders’ equity related to issuance of exchangeable debt	—			(14.7		)	—
	Balance at end of year	$	764.1		$	873.1		$	22.3
Schedule of Components of Income Tax Expense (Benefit)	'
	Significant components of income tax expense (benefit) are as follows:
		2013			2012			2011
	Current:
	Federal	$	(3.4	)	$	—		$	—
	State	0.2			1			(2.1		)
	Foreign	1.9			1.9			1.8
	Noncontrolling interests	—			17.6			(2.8		)
	Deferred:
	Federal	14			31.5			(84.9		)
	State	1.2			2.8			(6.0		)
	Amount allocated to other comprehensive income	(22.7		)	—			—
	Change in valuation allowance on beginning-of-the-year deferred tax assets	(1.6		)	735.2			—
	Income tax expense (benefit)	$	(10.4	)	$	790		$	(94.0	)
Schedule of Effective Income Tax Rate Reconciliation	'
	The reconciliation of income tax on income (loss) before income taxes computed at the U.S. federal statutory tax rates to actual income tax expense (benefit) is as follows:
		2013			2012			2011
	Income tax expense (benefit) at U.S. federal statutory rate	$	2.4		$	(73.0	)	$	(89.0	)
	Income tax expense on noncontrolling interest earnings not taxable to the Company	(22.5		)	—			—
	State and foreign tax expense, net of federal tax	1.7			(4.8		)	(9.9		)
	Increase in deferred tax asset valuation allowance	21.9			865.5			—
	Amount allocated to other comprehensive income	(22.7		)	—			—
	Effect of state law changes on deferred tax assets, net of federal tax	—			—			2
	Change in accrual for uncertain tax positions	(1.7		)	—			—
	Stock compensation in excess of tax deduction	3.1			—			—
	Expiration of charitable contribution carryforwards	2.5			—			—
	Other permanent differences	4.9			2.3			2.9
	Income tax expense (benefit)	$	(10.4	)	$	790		$	(94.0	)
Schedule of Unrecognized Tax Benefits Roll Forward	'
	A reconciliation of the change in federal and state unrecognized tax benefits for 2013, 2012 and 2011 is presented below:
		2013			2012			2011
	Balance at beginning of year	$	54		$	49.2		$	50.3
	Increases (decreases) for prior year tax positions	(0.8		)	1.6			1.3
	Increases (decreases) for current year tax positions	0.9			3.7			(0.7		)
	Increases (decreases) related to settlements	—			—			(0.2		)
	(Decreases) related to statute lapse	(0.3		)	(0.5		)	(1.5		)
	Balance at end of year	$	53.8		$	54		$	49.2

Longterm_Debt_and_Other_Financ1

Long-term Debt and Other Financing Long-term Debt and Other Financing (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Schedule of Long-term Debt Instruments	'
	At December 31, 2013 and 2012, the Company’s debt balances, including current portions, were as follows:
		2013			2012
	Credit Facility	$	90		$	—
	8.75% Senior Secured Notes due December 2018	380			350
	5.00% Exchangeable Senior Notes due November 2019 (effective rate of 10.8%)	150			150
	7.625% Senior Notes due May 2020	529.8			550
	8.375% Senior Notes due April 2022	290.2			300
	Industrial Revenue Bonds due 2014 through 2030	100.1			100.9
	Unamortized debt discount/premium, net	(33.1		)	(39.0		)
	Total debt	1,507.00			1,411.90
	Less:
	Current portion of long-term debt	0.8			0.7
	Total long-term debt	$	1,506.20		$	1,411.20
Schedule of Maturities of Long-term Debt	'
	At December 31, 2013, the maturities of long-term debt, including the amount outstanding on the Credit Facility, for the next five years are as follows:
	Year		Debt Maturities
	2014		$	0.8
	2015		—
	2016		90
	2017		—
	2018		380

Pension_and_Other_Postretireme1

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
Schedule of Defined Benefit Plans Disclosures	'
	The information below include amounts calculated based on benefit obligation and asset valuation measurement dates of December 31, 2013 and 2012.
		Pension Benefits								Other Benefits
		2013				2012				2013			2012
	Change in benefit obligations:
	Benefit obligations at beginning of year	$	3,759.40			$	3,539.50			$	602		$	713.2
	Service cost	2.4				3.2				4.7			4.6
	Interest cost	138.8				160.2				21			31.5
	Plan participants’ contributions	—				—				27			28.9
	Actuarial loss (gain)	(214.8		)		364.2				(54.3		)	35.9
	Amendments	6				3.5				—			(87.4		)
	Contributions to Butler and Zanesville retirees’ VEBA trusts	—				—				(30.8		)	(31.7		)
	Benefits paid	(311.4		)		(311.3		)		(95.6		)	(101.4		)
	Medicare subsidy reimbursement received	—				—				5.2			8.4
	Foreign currency exchange rate changes	0.2				0.1				—			—
	Benefit obligations at end of year	$	3,380.60			$	3,759.40			$	479.2		$	602
	Change in plan assets:
	Fair value of plan assets at beginning of year	$	2,591.10			$	2,377.90			$	—		$	—
	Actual gain on plan assets	337.7				347.8				—			—
	Employer contributions	191.1				176.7				63.4			64.1
	Plan participants’ contributions	—				—				27			28.9
	Benefits paid	(311.4		)		(311.3		)		(95.6		)	(101.4		)
	Medicare subsidy reimbursement received	—				—				5.2			8.4
	Fair value of plan assets at end of year	$	2,808.50			$	2,591.10			$	—		$	—
	Funded status	$	(572.1	)		$	(1,168.3	)		$	(479.2	)	$	(602.0	)
	Amounts recognized in the consolidated balance sheets:
	Current liabilities	$	(17.5	)		$	(5.7	)		$	(68.4	)	$	(102.9	)
	Noncurrent liabilities	(554.6		)		(1,162.6		)		(410.8		)	(499.1		)
	Total	$	(572.1	)		$	(1,168.3	)		$	(479.2	)	$	(602.0	)
	Amounts recognized in accumulated other comprehensive income, before tax:
	Actuarial loss (gain)	$	(16.7	)		$	374.2			$	(19.8	)	$	36.8
	Prior service cost (credit)	18.5				16.3				(318.4		)	(398.4		)
	Total	$	1.8			$	390.5			$	(338.2	)	$	(361.6	)
Schedule of Assumptions Used	'
	Assumptions used to value benefit obligations and determine pension and OPEB expense (income) are as follows:
		Pension Benefits									Other Benefits
		2013			2012			2011			2013		2012			2011
	Assumptions used to determine benefit obligations at December 31:
	Discount rate	4.53	%		3.85	%		4.74	%		4.48	%	3.77	%		4.72	%
	Rate of compensation increase	4	%		4	%		4	%		4	%	4	%		4	%
	Subsequent year healthcare cost trend rate										7	%	7.5	%		7.5	%
	Ultimate healthcare cost trend rate										4.5	%	4.5	%		4.5	%
	Year ultimate healthcare cost trend rate begins										2019		2019			2018
	Assumptions used to determine pension and OPEB expense (income) for the year ended December 31:
	Discount rate	3.85	%		4.74	%		5.36	%		3.77	%	4.72	%		5.18	%
	Expected return on plan assets	7.25	%		8	%		8.5	%
	Rate of compensation increase	4	%		4	%		4	%		4	%	4	%		4	%
Schedule of Change in Assumed Health Care Cost Trend Rates	'
	As of December 31, 2013, a one-percentage-point change in the assumed healthcare cost trend rates would have the following effects:
		One Percentage Point
		Increase				Decrease
	Effect on total service cost and interest cost components	$	0.1			$	(0.1	)
	Effect on postretirement benefit obligation	3.3				(3.2		)
Schedule of Expected Benefit Payments	'
	The following presents estimated future benefit payments to beneficiaries:
		Pension				Other				Medicare
		Plans				Benefits				Subsidy
						(a)				(a)
	2014	$	315.6			$	70.7			$	(5.4	)
	2015	299.1				49.3				(3.7		)
	2016	281.5				44.6				(3.4		)
	2017	299				41.9				(3.4		)
	2018	261.1				39.8				(3.3		)
	2019 through 2023	1,179.50				171.8				(15.9		)
	(a)	The amounts shown do not include the lump sum payments to the VEBA trust related to the Zanesville Retiree Settlement.  These amounts reflect the fact that the Company will have eliminated its OPEB liability related to the group of retirees covered by the Butler Retiree Settlement after 2014 and the Zanesville Retiree Settlement after 2015.
Schedule of Plan Assets	'
	The following table sets forth by level within the fair value hierarchy a summary of the plan’s investments measured at fair value on a recurring basis at December 31, 2013 and 2012. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. See Note 15 for more information on the determination of fair value.
			Quoted Prices								Significant Other							Significant
			in Active								Observable Inputs							Unobservable
			Markets for															Inputs
			Identical Assets
			(Level 1)								(Level 2)							(Level 3)						Total
			2013				2012				2013			2012				2013			2012			2013		2012
	Equity Investments:
	U.S. securities		$	176.6			$	108.1			$	—		$	—			$	—		$	—		$	176.6	$	108.1
	U.S. common/collective trusts		—				—				840.5			808.3				—			—			840.5		808.3
	EAFE common/collective trusts		—				—				277.6			256.8				—			—			277.6		256.8
	Emerging market securities		79.4				60.9				—			—				—			—			79.4		60.9
	Emerging market common/collective trusts		—				—				128.1			134.7				—			—			128.1		134.7
	Global investments		—				—				230.8			187.1				—			—			230.8		187.1
	Fixed Income Investments:
	U.S. investment-grade corporate common/collective trusts		—				—				378.4			333.4				—			—			378.4		333.4
	U.S. treasuries common/collective trusts		—				—				88.1			98.4				—			—			88.1		98.4
	Mortgage-backed common/collective trusts		—				—				20.5			15.6				—			—			20.5		15.6
	Global investments		—				—				350.8			359.6				—			—			350.8		359.6
	U.S. high-yield corporate securities		—				—				191.6			175				—			—			191.6		175
	Other Investments:
	Private equity funds (a)		—				—				—			—				0.6			3.2			0.6		3.2
	Cash and cash equivalents		45.5				50				—			—				—			—			45.5		50
	Total		$	301.5			$	219			$	2,506.40		$	2,368.90			$	0.6		$	3.2		$	2,808.50	$	2,591.10
	(a)	Consists of private equity funds that have no remaining capital commitments due from the Company.
Schedule of Changes in Plan Assets for Level 3 Assets	'
	The following sets forth activity for Level 3 assets for 2013 and 2012:
	Level 3 Assets		Private Equity Funds
	December 31, 2011		$	2.5
	Unrealized gains		1.3
	Distribution to master pension trust		(0.6		)
	December 31, 2012		$	3.2
	Distribution to master pension trust		(2.6		)
	December 31, 2013		$	0.6
Schedule of Net Benefit Costs	'
	The components of pension and OPEB expense (income) for the years 2013, 2012 and 2011 are as follows:
		Pension Benefits											Other Benefits
		2013				2012				2011			2013				2012			2011
	Components of pension and OPEB expense (income):
	Service cost	$	2.4			$	3.2			$	3.2		$	4.7			$	4.6		$	4.2
	Interest cost	138.8				160.2				180.8			21				31.5			37.9
	Expected return on plan assets	(184.5		)		(188.3		)		(207.5		)	—				—			—
	Amortization of prior service cost (credit)	3.8				3.8				4			(80.0		)		(77.4		)	(76.6		)
	Reversal of prior amortization related to Zanesville and Butler Retiree Settlements	—				—				—			—				2.5			14.2
	Recognized net actuarial loss (gain):
	Annual amortization	23.6				24.5				18.8			2.4				0.1			(1.0		)
	Pension corridor charge	—				157.3				268.1			—				—			—
	Settlement gain	(0.8		)		—				—			—				—			(14.0		)
	Pension and OPEB expense (income)	$	(16.7	)		$	160.7			$	267.4		$	(51.9	)		$	(38.7	)	$	(35.3	)
Schedule of Multiemployer Plans	'
	The Company’s participation in these plans for the years ended December 31, 2013, 2012 and 2011, is outlined in the table below. The Company does not provide more than five percent of the total contributions to any multiemployer plan. Forms 5500 are not yet available for plan years ending in 2013.
	Pension Fund		EIN/Pension Plan Number		Pension Protection Act Zone Status (a)				FIP/RP Status Pending/Implemented (b)		Contributions										Surcharge Imposed (c)		Expiration Date of Collective Bargaining Agreement
					2013		2012				2013			2012				2011
	Steelworkers Pension Trust		23-6648508/499		Green		Green		No		$	7.3		$	7			$	7.2		No		3/31/2014 to 3/1/2015 (d)
	IAM National Pension Fund’s National Pension Plan		51-6031295/002		Green		Green		No		14.8			12.6				12.3			No		9/15/2014 to 10/1/2016 (e)
	Other (f)										—			—				0.5
											$	22.1		$	19.6			$	20
	(a)	The most recent Pension Protection Act zone status available in 2013 and 2012 is for each plan’s year-end at December 31, 2012 and 2011, respectively. The zone status is based on information that the Company received from the plan and is certified by the plan’s actuary. Generally, plans in the red zone are less than 65% funded, plans in the yellow zone are between 65% and 80% funded, and plans in the green zone are at least 80% funded. The Steelworkers Pension Trust and IAM National Pension Fund’s National Pension Plan elected funding relief under section 431(b)(8) of the Internal Revenue Code and section 304(b)(8) of the Employment Retirement Income Security Act of 1974 (ERISA). This election allows those plans’ investment losses for the plan year ended December 31, 2008, to be amortized over 29 years for funding purposes.
	(b)	The “FIP/RP Status Pending/Implemented” column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented, as defined by ERISA.
	(c)	The surcharge represents an additional required contribution due as a result of the critical funding status of the plan.
	(d)	The Company or its AK Tube subsidiary is a party to three collective bargaining agreements (at its Ashland Works, Mansfield Works and at the AK Tube Walbridge plant) that require contributions to the Steelworkers Pension Trust. The labor contract for approximately 280 hourly employees at Mansfield Works expires on March 31, 2014. The labor contract for approximately 90 hourly employees at the AK Tube Walbridge, OH plant expires January 22, 2015. The labor contract for approximately 820 hourly employees at the Ashland Works expires on March 1, 2015.
	(e)	The Company is a party to three collective bargaining agreements (at its Middletown Works, Zanesville Works and Butler Works) that require contributions to the IAM National Pension Fund’s National Pension Plan. The labor contract for approximately 1,650 hourly employees at Middletown Works expires on September 15, 2014. The labor contract for approximately 160 hourly employees at Zanesville Works expires on May 20, 2015. The labor contract for approximately 1,200 hourly employees at Butler Works expires on October 1, 2016.
	(f)	The Company was a party to a collective bargaining agreement at its former Ashland coke plant that required contributions to the PACE Industry Union-Management Pension Fund. The Company has now withdrawn from this plan and paid the withdrawal liability of $1.8 in 2012.

Operating_Leases_Tables

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Future minimum lease payments	'
	At December 31, 2013, obligations to make future minimum lease payments were as follows:
	2014	$	8.9
	2015	7.1
	2016	5
	2017	4.7
	2018	4.3
	2019 and thereafter	7.3
	Total minimum lease payments	$	37.3

Environmental_and_Legal_Contin1

Environmental and Legal Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of environmental-related capital investments and compliance costs	'
	Over the past three years, the Company has expended the following for environmental-related capital investments and environmental compliance:
		2013			2012			2011
	Environmental-related capital investments	$	1.6		$	1		$	1.7
	Environmental compliance costs	101.1			101.6			106.4
Schedule of accrual of liabilities related to environmental loss contingencies	'
	Liabilities recorded on the Consolidated Balance Sheets for such estimated probable costs relating to environmental matters are presented below:
		2013			2012
	Accrued liabilities	$	9.5		$	19.6
	Other non-current liabilities	34.1			27.4
Schedule of information on pending asbestos cases	'
	Information on asbestos cases pending at December 31, 2013, is presented below:
			Asbestos Cases Pending at
			December 31, 2013
	Cases with specific dollar claims for damages:
	Claims up to $0.2			121
	Claims above $0.2 to $5.0			6
	Claims above $5.0 to $15.0			2
	Claims above $15.0 to $20.0			2
	Total claims with specific dollar claims for damages (a)			131
	Cases without a specific dollar claim for damages			305
	Total asbestos cases pending			436
	(a)	Involve a total of 2,387 plaintiffs and 17,623 defendants
Schedule of number of new asbestos claims filed, number of pending asbestos claims disposed, and amount paid in settlements	'
	Set forth below is a chart showing the number of new claims filed (accounted for as described above), the number of pending claims disposed of (i.e., settled or otherwise dismissed), and the approximate net amount of dollars paid on behalf of AK Steel in settlement of asbestos-related claims in 2013, 2012 and 2011.
			2013			2012			2011
	New Claims Filed		42			50			31
	Pending Claims Disposed Of		39			24			44
	Total Amount Paid in Settlements		$	1		$	0.8		$	0.7

Sharebased_Compensation_Tables

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of information about share-based compensation expense	'
	The following table summarizes information about share-based compensation expense for the years ended December 31, 2013, 2012 and 2011:
	Share-based Compensation Expense		2013				2012			2011
	Stock options		$	1.5			$	2.4		$	2.3
	Restricted stock		2.9				5.3			5.9
	Restricted stock units issued to Directors		1				0.9			0.9
	Performance shares		4.1				6			5.8
	Pre-tax share-based compensation expense		$	9.5			$	14.6		$	14.9
Schedule of weighted-average assumptions used in Black-Scholes option calculation	'
	The Company’s estimate of fair value of options granted is calculated as of the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions:
			2013				2012			2011
	Expected volatility		57.8% – 68.8%				63.2% – 73.2%			59.7% – 78.0%
	Weighted-average volatility		65.2		%		69.4		%	62.1		%
	Expected term (in years)		2.9-6.4				2.8 – 6.3			2.7 – 6.3
	Risk-free interest rate		0.4% - 1.1%				0.3% - 1.2%			0.4% – 2.6%
	Dividend yield		—		%		2.2		%	1.4		%
	Weighted-average grant-date fair value per share of options granted		$	2.44			$	4.31		$	6.83
Schedule of stock options activity	'
	A summary of option activity for the year ended December 31, 2013, is presented below:
	Stock Options			Shares			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Life (in years)		Aggregate Intrinsic Value
	Outstanding at December 31, 2012			1,819,382			$	14.46
	Granted			502,750			4.58
	Exercised			(15,000	)		4.57
	Canceled			(113,600	)		14.64
	Outstanding at December 31, 2013			2,193,532			12.26			5.9		$	1.9
	Exercisable at December 31, 2013			1,283,599			15.85			4.7		0.1
	Unvested at December 31, 2013			909,933			7.19			7.7		1.8
	Unvested at December 31, 2013 expected to vest			864,436			7.19			7.7		1.7
Schedule of nonvested restricted stock units activity	'
	A summary of the activity for non-vested restricted stock awards for the year ended December 31, 2013, is presented below:
	Restricted Stock Awards	Restricted Shares			Weighted- Average Grant Date Fair Value
	Outstanding at December 31, 2012	398,113			$	11.33
	Granted	550,581			4.43
	Vested/restrictions lapsed	(466,641	)		8.14
	Canceled	(48,824	)		8.02
	Outstanding at December 31, 2013	433,229			6.35
Schedule of weighted-average assumptions used in Monte Carlo simulation	'
	The Company’s estimate of fair value of performance shares granted is calculated as of the date of grant using a Monte Carlo simulation model with the following weighted-average assumptions:
			2013				2012			2011
	Company expected volatility		59.2		%		69.4		%	89		%
	S&P’s MidCap 400 index expected volatility		34.7		%		42.2		%	52.4		%
	Risk-free interest rate		0.4		%		0.4		%	1		%
	Dividend yield		—		%		2.2		%	1.4		%
	Weighted-average grant-date fair value per performance share granted		$	4.68			$	9.89		$	15.78
Schedule of nonvested performance-based units activity	'
	A summary of the activity for non-vested performance share awards for the year ended December 31, 2013, is presented below:
	Performance Share Awards	Performance Shares			Weighted- Average Grant Date Fair Value
	Outstanding at December 31, 2012	942,313			$	12.24
	Granted	585,450			4.68
	Earned	—			—
	Expired or forfeited	(474,990	)		14.02
	Outstanding at December 31, 2013	1,052,773			7.23

Comprehensive_Income_Loss_Tabl

Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]	'
Accumulated Other Comprehensive Income (Loss), Net of Tax	'
	The details of other comprehensive income (loss), net of tax, are as follows:
			2013
	Foreign currency translation
	Balance at beginning of period		$	3.5
	Other comprehensive income (loss):
	Foreign currency translation gain (loss)		1.2
	Balance at end of period		$	4.7
	Cash flow hedges
	Balance at beginning of period		$	31.7
	Other comprehensive income (loss):
	Gains (losses) arising in period		3.5
	Income tax expense (benefit)		1.3
	Gains (losses) arising in period, net of tax		2.2
	Reclassification of losses (gains) to net income (loss):
	Hot roll carbon steel coil contracts (a)		(0.4		)
	Other commodity contracts (b)		(24.8		)
	Subtotal		(25.2		)
	Income tax (expense) benefit (d)		(9.6		)
	Net amount of reclassification of losses (gains) to net income (loss)		(15.6		)
	Total other comprehensive income (loss), net of tax		(13.4		)
	Balance at end of period		$	18.3
	Unrealized holding gains (losses) on securities
	Balance at beginning of period		$	0.3
	Other comprehensive income (loss):
	Unrealized holding gains (losses) arising in period		0.2
	Income tax expense (benefit)		0.1
	Unrealized holding gains (losses) arising in period, net of tax		0.1
	Balance at end of period		$	0.4
	Pension and OPEB plans
	Balance at beginning of period		$	(34.4	)
	Other comprehensive income (loss):
	Prior service credit (cost) arising in period		(6.1		)
	Gains (losses) arising in period		422.3
	Subtotal		416.2
	Income tax expense (benefit)		50.3
	Gains (losses) arising in period, net of tax		365.9
	Reclassification to net income (loss):
	Prior service costs (credits) (c)		(76.2		)
	Actuarial (gains) losses (c)		25.3
	Subtotal		(50.9		)
	Income tax (expense) benefit (d)		(19.4		)
	Amount of reclassification to net income (loss), net of tax		(31.5		)
	Total other comprehensive income (loss), net of tax		334.4
	Balance at end of period		$	300
	(a)	Amounts are included in net sales on the Consolidated Statements of Operations.
	(b)	Amounts are included in cost of products sold on the Consolidated Statements of Operations.
	(c)	Amounts are included in pension and OPEB expense (income) on the Consolidated Statements of Operations.
	(d)	Amounts are included in income tax expense (benefit) on the Consolidated Statements of Operations.
Schedule of Tax Effects Allocated to Each Component of Other Comprehensive Income Loss [Table Text Block]	'
	The tax effects allocated to each component of other comprehensive income (loss) in 2011 are as follows:
			2011
	Cash flow hedges:
	Gains (losses) arising in period		$	(8.0	)
	Reclassification of loss (gain) to net income (loss)		1.5
	Unrealized holding gain (loss) on securities:
	Unrealized holding gain (loss) arising in period		(0.2		)
	Pension and OPEB plans:
	Prior service cost arising in period		(7.5		)
	Reclassification of prior service cost (credits) included in net income (loss)		(22.3		)
	Gains (losses) arising in period		(122.2		)
	Reclassification of losses (gains) included in net income (loss)		103.9
	Income tax expense (benefit) allocated to other comprehensive income (loss)		$	(54.8	)

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings per share	'
	Reconciliation of the numerators and denominators for basic and diluted EPS computations is as follows:
		2013			2012			2011
	Net income (loss) attributable to AK Steel Holding Corporation	$	(46.8	)	$	(1,027.3	)	$	(155.6	)
	Less: distributed earnings to common stockholders and holders of certain stock compensation awards	—			11			22
	Undistributed earnings (loss)	$	(46.8	)	$	(1,038.3	)	$	(177.6	)
	Common stockholders earnings—basic and diluted:
	Distributed earnings to common stockholders	$	—		$	11		$	22
	Undistributed earnings (loss) to common stockholders	(46.6		)	(1,034.6		)	(176.9		)
	Common stockholders earnings (loss)—basic and diluted	$	(46.6	)	$	(1,023.6	)	$	(154.9	)
	Common shares outstanding (weighted-average shares in millions):
	Common shares outstanding for basic earnings per share	135.8			113			109.8
	Effect of exchangeable debt	—			—			—
	Effect of dilutive stock-based compensation	—			—			—
	Common shares outstanding for diluted earnings per share	135.8			113			109.8
	Basic and diluted earnings per share:
	Distributed earnings	$	—		$	0.1		$	0.2
	Undistributed earnings (loss)	(0.34		)	(9.16		)	(1.61		)
	Basic and diluted earnings (loss) per share	$	(0.34	)	$	(9.06	)	$	(1.41	)
	Potentially issuable common shares (in millions) excluded from earnings per share calculation due to anti-dilutive effect	2.6			2.4			1.2

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair value assets and liabilities measured on a recurring basis	'
	The following fair value table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of the dates indicated:
		2013								2012
		Level 1		Level 2			Total			Level 1		Level 2			Total
	Assets measured at fair value
	Cash and cash equivalents	$	45.3	$	—		$	45.3		$	227	$	—		$	227
	Other current assets—commodity hedge contracts	—		4.9			4.9			—		25.5			25.5
	Other non-current assets:
	Available for sale investments—cash and cash equivalents	18.6		—			18.6			26.3		—			26.3
	Assets measured at fair value	$	63.9	$	4.9		$	68.8		$	253.3	$	25.5		$	278.8
	Liabilities measured at fair value
	Accrued liabilities:
	Foreign exchange contracts	$	—	$	(0.7	)	$	(0.7	)	$	—	$	(0.2	)	$	(0.2	)
	Commodity hedge contracts	—		(0.4		)	(0.4		)	—		(1.3		)	(1.3		)
	Other non-current liabilities—commodity hedge contracts	—		(0.1		)	(0.1		)	—		—			—
	Liabilities measured at fair value	$	—	$	(1.2	)	$	(1.2	)	$	—	$	(1.5	)	$	(1.5	)
	Liabilities measured at other than fair value
	Long-term debt, including current portions:
	Fair value	$	—	$	(1,659.9	)	$	(1,659.9	)	$	—	$	(1,379.3	)	$	(1,379.3	)
	Carrying amount	—		(1,507.0		)	(1,507.0		)	—		(1,411.9		)	(1,411.9		)

Disclosures_About_Derivative_I1

Disclosures About Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Outstanding commodity price swaps and options and forward foreign exchange contracts	'
	As of December 31, 2013 and 2012, the Company had the following outstanding commodity price swaps and options and forward foreign exchange contracts:
	Commodity		2013			2012
	Nickel (in lbs)		763,300			420,100
	Natural gas (in MMBTUs)		3,240,000			9,000,000
	Zinc (in lbs)		12,000,000			—
	Iron ore (in metric tons)		190,735			1,140,000
	Hot roll carbon steel coils (in short tons)		74,147			30,000
	Foreign exchange contracts (in euros)		€	17,730,000		€	15,950,000
Fair value of derivative instruments in the Condensed Consolidated Balance Sheets	'
	The following table presents the fair value of derivative instruments in the Consolidated Balance Sheets as of December 31, 2013 and 2012:
	Asset (liability)		2013			2012
	Derivatives designated as hedging instruments:
	Other current assets—commodity contracts		$	2.6		$	25.5
	Accrued liabilities—commodity contracts		—			(1.2		)
	Derivatives not designated as hedging instruments:
	Other current assets—commodity contracts		2.3			—
	Accrued liabilities:
	Foreign exchange contracts		(0.7		)	(0.2		)
	Commodity contracts		(0.4		)	(0.1		)
	Other noncurrent liabilities—commodity contracts		(0.1		)	—
Gains (losses) on derivative instruments included in the Condensed Consolidated Statements of Operations	'
	The following table presents gains (losses) on derivative instruments included in the Consolidated Statements of Operations for the years ended December 31, 2013, 2012 and 2011:
	Gain (loss)		2013			2012			2011
	Derivatives in cash flow hedging relationships—
	Commodity contracts:
	Reclassified from accumulated other comprehensive income into net sales (effective portion)		$	0.4		$	—		$	—
	Reclassified from accumulated other comprehensive income into cost of products sold (effective portion)		24.8			(36.3		)	(4.0		)
	Recorded in cost of products sold (ineffective portion and amount excluded from effectiveness testing)		3.3			0.1			(10.2		)
	Derivatives not designated as hedging instruments:
	Foreign exchange contracts—recognized in other income (expense)		(0.1		)	(1.2		)	0.8
	Commodity contracts:
	Recognized in net sales		(3.1		)	—			—
	Recognized in cost of products sold		1.7			(0.6		)	(5.1		)
Amount of gains (losses) expected to be reclassified into earnings within the next twelve months	'
	The following table lists the amount of gains (losses) before tax expected to be reclassified into earnings within the next twelve months for the Company’s existing commodity contracts that qualify for hedge accounting, as well as the period of time over which the Company is hedging its exposure to the volatility in future cash flows:
	Commodity Hedge	Settlement Dates		Gains (losses)
	Natural gas	January 2014 to December 2014		$	2.3
	Zinc	January 2014 to December 2014		0.5

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]	'
Schedule of cash flow, supplemental disclosures	'
	The following table presents the net cash paid (received) during the period for interest, net of capitalized interest, and income taxes:
		2013		2012		2011
	Net cash paid (received) during the period for:
	Interest, net of capitalized interest	$	116.2	$	69.5	$	44.3
	Income taxes	1.2		1.3		0.1
Schedule of non-cash investing and financing activities	'
	The amounts of non-cash investing and financing activities for the years ended December 31, 2013, 2012 and 2011, were as follows:
		2013		2012		2011
	Capital investments	$	10.2	$	13.9	$	10.2
	Capital investments—SunCoke Middletown	—		—		16.3
	Issuance of restricted stock and restricted stock units	3		5.4		5.7
	Issuance of note payable for AK Coal purchase (at fair value)	—		—		10.2

Consolidated_Quarterly_Sales_a1

Consolidated Quarterly Sales and Earning (Losses) (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Information	'
	Earnings per share for each quarter and the year are calculated individually and may not sum to the total for the year.
		2013
		First			Second			Third			Fourth			Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	1,369.80		$	1,404.50		$	1,331.30		$	1,464.80		$	5,570.40
	Operating profit	33.2			13.7			25.9			63			135.8
	Net income (loss) attributable to AK Holding	(9.9		)	(40.4		)	(31.7		)	35.2			(46.8		)
	Basic and diluted earnings (loss) per share	$	(0.07	)	$	(0.30	)	$	(0.23	)	$	0.26		$	(0.34	)
		2012
		First			Second			Third			Fourth			Year
		Quarter			Quarter			Quarter			Quarter
	Net sales	$	1,508.70		$	1,538.40		$	1,463.50		$	1,423.10		$	5,933.70
	Operating profit (loss)	4.1			56.7			(12.0		)	(176.9		)	(128.1		)
	Net income (loss) attributable to AK Holding	(11.8		)	(724.2		)	(60.9		)	(230.4		)	(1,027.3		)
	Basic and diluted earnings (loss) per share	$	(0.11	)	$	(6.55	)	$	(0.55	)	$	(1.89	)	$	(9.06	)

Supplemental_Guarantor_Informa1

Supplemental Guarantor Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Guarantor Information [Abstract]	'
Condensed Statements of Comprehensive Income (Loss)	'
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2013
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	5,339.30		$	830.3		$	(599.2	)	$	5,570.40
	Cost of products sold (exclusive of items shown separately below)	—			5,012.10			652.3			(556.6		)	5,107.80
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			205			36.7			(40.8		)	205.3
	Depreciation	—			169.4			20.7			—			190.1
	Pension and OPEB expense (income)	—			(68.6		)	—			—			(68.6		)
	Total operating costs	4.4			5,317.90			709.7			(597.4		)	5,434.60
	Operating profit (loss)	(4.4		)	21.4			120.6			(1.8		)	135.8
	Interest expense	—			125.9			1.5			—			127.4
	Other income (expense)	—			(5.9		)	4.5			—			(1.4		)
	Income (loss) before income taxes	(4.4		)	(110.4		)	123.6			(1.8		)	7
	Income tax expense (benefit)	—			(27.8		)	18.1			(0.7		)	(10.4		)
	Equity in net income (loss) of subsidiaries	(42.4		)	40.2			—			2.2			—
	Net income (loss)	(46.8		)	(42.4		)	105.5			1.1			17.4
	Less: Net income (loss) attributable to noncontrolling interests	—			—			64.2			—			64.2
	Net income (loss) attributable to AK Steel Holding Corporation	(46.8		)	(42.4		)	41.3			1.1			(46.8		)
	Other comprehensive income (loss)	322.3			322.3			1.2			(323.5		)	322.3
	Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	275.5		$	279.9		$	42.5		$	(322.4	)	$	275.5
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2012
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	5,676.60		$	906.3		$	(649.2	)	$	5,933.70
	Cost of products sold (exclusive of items shown separately below)	—			5,416.80			738			(615.7		)	5,539.10
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			212.9			35.3			(43.9		)	208.7
	Depreciation	—			172.8			19.2			—			192
	Pension and OPEB expense (income) (exclusive of corridor charge shown below)	—			(35.3		)	—			—			(35.3		)
	Pension corridor charge	—			157.3			—			—			157.3
	Total operating costs	4.4			5,924.50			792.5			(659.6		)	6,061.80
	Operating profit (loss)	(4.4		)	(247.9		)	113.8			10.4			(128.1		)
	Interest expense	—			85.9			0.8			—			86.7
	Other income (expense)	—			(9.6		)	15.8			—			6.2
	Income (loss) before income taxes	(4.4		)	(343.4		)	128.8			10.4			(208.6		)
	Income tax expense (benefit)	—			735.9			49.9			4.2			790
	Equity in net income (loss) of subsidiaries	(1,022.9		)	56.4			—			966.5			—
	Net income (loss)	(1,027.3		)	(1,022.9		)	78.9			972.7			(998.6		)
	Less: Net income (loss) attributable to noncontrolling interests	—			—			28.7			—			28.7
	Net income (loss) attributable to AK Steel Holding Corporation	(1,027.3		)	(1,022.9		)	50.2			972.7			(1,027.3		)
	Other comprehensive income (loss)	(1.6		)	(1.6		)	0.7			0.9			(1.6		)
	Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	(1,028.9	)	$	(1,024.5	)	$	50.9		$	973.6		$	(1,028.9	)
	Condensed Statements of Comprehensive Income (Loss)
	Year Ended December 31, 2011
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net sales	$	—		$	6,205.90		$	756.7		$	(494.6	)	$	6,468.00
	Cost of products sold (exclusive of items shown separately below)	—			5,854.10			635.1			(452.4		)	6,036.80
	Selling and administrative expenses (exclusive of items shown separately below)	4.4			222.3			36.4			(47.7		)	215.4
	Depreciation	—			177.4			7.6			—			185
	Pension and OPEB expense (income) (exclusive of corridor charge shown below)	—			(36.0		)	—			—			(36.0		)
	Pension corridor charge	—			268.1			—			—			268.1
	Total operating costs	4.4			6,485.90			679.1			(500.1		)	6,669.30
	Operating profit (loss)	(4.4		)	(280.0		)	77.6			5.5			(201.3		)
	Interest expense	—			47.3			0.2			—			47.5
	Other income (expense)	—			(8.4		)	3.1			—			(5.3		)
	Income (loss) before income taxes	(4.4		)	(335.7		)	80.5			5.5			(254.1		)
	Income tax expense (benefit)	(1.8		)	(125.6		)	31.2			2.2			(94.0		)
	Equity in net income (loss) of subsidiaries	(153.0		)	57.1			—			95.9			—
	Net income (loss)	(155.6		)	(153.0		)	49.3			99.2			(160.1		)
	Less: Net income (loss) attributable to noncontrolling interests	—			—			(4.5		)	—			(4.5		)
	Net income (loss) attributable to AK Steel Holding Corporation	(155.6		)	(153.0		)	53.8			99.2			(155.6		)
Other comprehensive income (loss)	(89.9		)	(89.9		)	(0.7		)	90.6			(89.9		)
Comprehensive income (loss) attributable to AK Steel Holding Corporation	$	(245.5	)	$	(242.9	)	$	53.1		$	189.8		$	(245.5	)
Condensed Balance Sheets	'
	Condensed Balance Sheets
	December 31, 2013
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	ASSETS
	Current assets:
	Cash and cash equivalents	$	—		$	16.8		$	28.5		$	—		$	45.3
	Accounts receivable, net	—			492.4			61.1			(28.3		)	525.2
	Inventory, net	—			520			77.7			(11.1		)	586.6
	Deferred tax assets, current	—			69.4			0.2			—			69.6
	Other current assets	0.3			43.9			2.3			—			46.5
	Total current assets	0.3			1,142.50			169.8			(39.4		)	1,273.20
	Property, plant and equipment	—			5,258.40			613.5			—			5,871.90
	Accumulated depreciation	—			(3,881.7		)	(110.1		)	—			(3,991.8		)
	Property, plant and equipment, net	—			1,376.70			503.4			—			1,880.10
	Other non-current assets:
	Investment in Magnetation LLC	—			—			187.8			—			187.8
	Investment in affiliates	(2,772.4		)	1,393.80			—			1,378.60			—
	Inter-company accounts	2,551.10			(3,479.7		)	896.7			31.9			—
	Other non-current assets	—			141			123.6			—			264.6
	TOTAL ASSETS	$	(221.0	)	$	574.3		$	1,881.30		$	1,371.10		$	3,605.70
	LIABILITIES AND EQUITY (DEFICIT)
	Current liabilities:
	Accounts payable	$	—		$	550.5		$	51.9		$	(0.6	)	$	601.8
	Accrued liabilities	—			133.6			9.3			—			142.9
	Current portion of long-term debt	—			0.8			—			—			0.8
	Current portion of pension and other postretirement benefit obligations	—			85.4			0.5			—			85.9
	Total current liabilities	—			770.3			61.7			(0.6		)	831.4
	Non-current liabilities:
	Long-term debt	—			1,506.20			—			—			1,506.20
	Pension and other postretirement benefit obligations	—			960.6			4.8			—			965.4
	Other non-current liabilities	—			109.6			0.4			—			110
	TOTAL LIABILITIES	—			3,346.70			66.9			(0.6		)	3,413.00
	Total stockholders’ equity (deficit)	(221.0		)	(2,772.4		)	1,400.70			1,371.70			(221.0		)
	Noncontrolling interests	—			—			413.7			—			413.7
	TOTAL EQUITY (DEFICIT)	(221.0		)	(2,772.4		)	1,814.40			1,371.70			192.7
	TOTAL LIABILITIES AND EQUITY (DEFICIT)	$	(221.0	)	$	574.3		$	1,881.30		$	1,371.10		$	3,605.70
	Condensed Balance Sheets
	December 31, 2012
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	ASSETS
	Current assets:
	Cash and cash equivalents	$	—		$	203.6		$	23.4		$	—		$	227
	Accounts receivable, net	—			484.4			54.3			(64.8		)	473.9
	Inventory, net	—			504.2			114.4			(9.4		)	609.2
	Deferred tax assets, current	—			73			0.2			—			73.2
	Other current assets	0.2			57.6			1.6			—			59.4
	Total current assets	0.2			1,322.80			193.9			(74.2		)	1,442.70
	Property, plant and equipment	—			5,355.10			588.8			—			5,943.90
	Accumulated depreciation	—			(3,841.9		)	(89.7		)	—			(3,931.6		)
	Property, plant and equipment, net	—			1,513.20			499.1			—			2,012.30
	Other non-current assets:
	Investment in Magnetation LLC	—			—			150			—			150
	Investment in affiliates	(2,660.7		)	1,337.40			—			1,323.30			—
	Inter-company accounts	2,155.20			(3,066.5		)	843.8			67.5			—
	Other non-current assets	—			167.7			130.4			—			298.1
	TOTAL ASSETS	$	(505.3	)	$	1,274.60		$	1,817.20		$	1,316.60		$	3,903.10
	LIABILITIES AND EQUITY (DEFICIT)
	Current liabilities:
	Accounts payable	$	—		$	494.8		$	44.4		$	(0.9	)	$	538.3
	Accrued liabilities	—			155			9.8			—			164.8
	Current portion of long-term debt	—			0.7			—			—			0.7
Current portion of pension and other postretirement benefit obligations	—			108.1			0.5			—			108.6
Total current liabilities	—			758.6			54.7			(0.9		)	812.4
Non-current liabilities:
Long-term debt	—			1,411.20			—			—			1,411.20
Pension and other postretirement benefit obligations	—			1,657.20			4.5			—			1,661.70
Other non-current liabilities	—			108.3			0.5			—			108.8
TOTAL LIABILITIES	—			3,935.30			59.7			(0.9		)	3,994.10
Total stockholders’ equity (deficit)	(505.3		)	(2,660.7		)	1,343.20			1,317.50			(505.3		)
Noncontrolling interests	—			—			414.3			—			414.3
TOTAL EQUITY (DEFICIT)	(505.3		)	(2,660.7		)	1,757.50			1,317.50			(91.0		)
TOTAL LIABILITIES AND EQUITY (DEFICIT)	$	(505.3	)	$	1,274.60		$	1,817.20		$	1,316.60		$	3,903.10
Condensed Statements of Cash Flows	'
	Condensed Statements of Cash Flows
	Year Ended December 31, 2013
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net cash flows from operating activities	$	(3.5	)	$	(251.1	)	$	180		$	(35.6	)	$	(110.2	)
	Cash flows from investing activities:
	Capital investments	—			(39.2		)	(24.4		)	—			(63.6		)
	Investments in acquired businesses	—			—			(50.0		)	—			(50.0		)
	Other investing items, net	—			8.5			6.6			—			15.1
	Net cash flows from investing activities	—			(30.7		)	(67.8		)	—			(98.5		)
	Cash flows from financing activities:
	Net borrowings (repayments) under credit facility	—			90			—			—			90
	Proceeds from issuance of long-term debt	—			31.9			—			—			31.9
	Redemption of long-term debt	—			(27.4		)	—			—			(27.4		)
	Debt issuance costs	—			(3.4		)	—			—			(3.4		)
	Inter-company activity	4.1			3.9			(43.6		)	35.6			—
	SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			(64.8		)	—			(64.8		)
	Other financing items, net	(0.6		)	—			1.3			—			0.7
	Net cash flows from financing activities	3.5			95			(107.1		)	35.6			27
	Net increase (decrease) in cash and cash equivalents	—			(186.8		)	5.1			—			(181.7		)
	Cash and equivalents, beginning of year	—			203.6			23.4			—			227
	Cash and equivalents, end of year	$	—		$	16.8		$	28.5		$	—		$	45.3
	Condensed Statements of Cash Flows
	Year Ended December 31, 2012
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net cash flows from operating activities	$	(3.5	)	$	(360.0	)	$	113.1		$	(20.4	)	$	(270.8	)
	Cash flows from investing activities:
	Capital investments	—			(38.3		)	(25.8		)	—			(64.1		)
	Investments in acquired businesses	—			—			(60.6		)	—			(60.6		)
	Other investing items, net	—			6.7			(0.6		)	—			6.1
	Net cash flows from investing activities	—			(31.6		)	(87.0		)	—			(118.6		)
	Cash flows from financing activities:
	Net borrowings (repayments) under credit facility	—			(250.0		)	—			—			(250.0		)
	Proceeds from issuance of long-term debt	—			873.3			—			—			873.3
	Redemption of long-term debt	—			(74.0		)	—			—			(74.0		)
	Proceeds from issuance of common stock	96.4			—			—			—			96.4
	Debt issuance costs	—			(22.3		)	—			—			(22.3		)
	Common stock dividends paid	(11.0		)	—			—			—			(11.0		)
	Inter-company activity	(80.2		)	48.8			11			20.4			—
	SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			(36.6		)	—			(36.6		)
	Other financing items, net	(1.7		)	(0.5		)	0.8			—			(1.4		)
	Net cash flows from financing activities	3.5			575.3			(24.8		)	20.4			574.4
	Net increase (decrease) in cash and cash equivalents	—			183.7			1.3			—			185
	Cash and equivalents, beginning of year	—			19.9			22.1			—			42
	Cash and equivalents, end of year	$	—		$	203.6		$	23.4		$	—		$	227
	Condensed Statements of Cash Flows
	Year Ended December 31, 2011
		AK			AK			Other Non-Guarantor Subsidiaries			Eliminations			Consolidated Company
		Holding			Steel
	Net cash flows from operating activities	$	(1.7	)	$	(216.9	)	$	39.7		$	(1.6	)	$	(180.5	)
	Cash flows from investing activities:
	Capital investments	—			(98.9		)	(197.2		)	—			(296.1		)
	Investments in acquired businesses	—			—			(125.4		)	—			(125.4		)
	Other investing items, net	—			1.4			(0.1		)	—			1.3
	Net cash flows from investing activities	—			(97.5		)	(322.7		)	—			(420.2		)
	Cash flows from financing activities:
	Net borrowings (repayments) under credit facility	—			250			—			—			250
	Redemption of long-term debt	—			(0.7		)	—			—			(0.7		)
	Debt issuance costs	—			(10.1		)	—			—			(10.1		)
	Common stock dividends paid	(22.0		)	—			—			—			(22.0		)
	Inter-company activity	25			(106.4		)	79.8			1.6			—
	SunCoke Middletown advances from (distributions to) noncontrolling interest owners	—			—			210.7			—			210.7
Other financing items, net	(1.3		)	0.1			(0.8		)	—			(2.0		)
Net cash flows from financing activities	1.7			132.9			289.7			1.6			425.9
Net increase (decrease) in cash and cash equivalents	—			(181.5		)	6.7			—			(174.8		)
Cash and equivalents, beginning of year	—			201.4			15.4			—			216.8
Cash and equivalents, end of year	$	—		$	19.9		$	22.1		$	—		$	42

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	employees								employees
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	$1,464.80	$1,331.30	$1,404.50	$1,369.80	$1,423.10	$1,463.50	$1,538.40	$1,508.70	$5,570.40	$5,933.70	$6,468
Number of Employees	6,400	'	'	'	'	'	'	'	6,400	'	'
Stainless And Electrical [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1,705.30	1,898.90	2,188.90
Carbon [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	3,643.40	3,789.60	4,009.50
Tubular [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	220.7	243.6	247.7
Other Product Lines [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	1	1.6	21.9
Workforce Subject to Collective Bargaining Arrangements [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Number of Employees	4,700	'	'	'	'	'	'	'	4,700	'	'
Steelworkers Pension Trust [Member] | Mansfield Works [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Number of Employees	280	'	'	'	'	'	'	'	280	'	'
IAM National Pension Fund's National Pension Plan [Member] | Middletown Works [Member] | Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Number of Employees	1,650	'	'	'	'	'	'	'	1,650	'	'
Customer Concentration Risk [Member] | Automotive Market [Member] | Sales Revenue, Goods, Net [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Percentage of total (in hundredths)	'	'	'	'	'	'	'	'	51.00%	45.00%	36.00%
Customer Concentration Risk [Member] | Infrastructure and Manufacturing Market [Member] | Sales Revenue, Goods, Net [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Percentage of total (in hundredths)	'	'	'	'	'	'	'	'	20.00%	23.00%	24.00%
Customer Concentration Risk [Member] | Distributors and Converters Market [Member] | Sales Revenue, Goods, Net [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Percentage of total (in hundredths)	'	'	'	'	'	'	'	'	29.00%	32.00%	40.00%
Customer Concentration Risk [Member] | Foreign Customers [Member] | Sales Revenue, Goods, Net [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net sales	'	'	'	'	'	'	'	'	$708	$856.70	$946.40
Credit Concentration Risk [Member] | Automotive Market [Member] | Accounts Receivable [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Of Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Percentage of total (in hundredths)	'	'	'	'	'	'	'	'	41.00%	43.00%	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Property Plant and Equipment Useful Lives (Details 2)	12 Months Ended
	Dec. 31, 2013
Land Improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Useful Life	'20 years
Buildings [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Useful Life	'40 years
Minimum [Member] | Machinery and equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Useful Life	'2 years
Maximum [Member] | Machinery and equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Useful Life	'20 years
Weighted Average [Member] | Machinery and equipment [Member]	'
Property, Plant and Equipment [Line Items]	'
Property, Plant and Equipment, Useful Life	'19 years 1 month

Supplementary_Financial_Statem2

Supplementary Financial Statement Information - Research & Development (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplementary Financial Statement Information [Abstract]	'	'	'
Research and development costs	$13.20	$12.50	$13.20

Supplementary_Financial_Statem3

Supplementary Financial Statement Information - Allowance for Doubtful Accounts (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance For Doubtful Accounts	'	'	'
Balance at beginning of year	$9.10	$11.90	$13.10
Increase (decrease) in allowance	-0.4	-2.7	-1.1
Receivables written off	-0.6	-0.1	-0.1
Balance at end of year	$8.10	$9.10	$11.90

Supplementary_Financial_Statem4

Supplementary Financial Statement Information - Inventory (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Inventory Disclosure [Abstract]	'	'	'	'
Finished and semi-finished	$722.20	$728.50	'	'
Raw materials	260.9	315.7	'	'
Total cost	983.1	1,044.20	'	'
Adjustment to state inventories at LIFO value	-396.5	-435	-524	-514.2
Inventory, net	586.6	609.2	'	'
Effect of LIFO inventory liquidation on income	$11.90	$0.90	$109.90	'

Supplementary_Financial_Statem5

Supplementary Financial Statement Information - LIFO Reserve (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in LIFO Reserve	'	'	'
Balance at beginning of year	$435	$524	$514.20
Change in reserve	-38.5	-89	9.8
Balance at end of year	$396.50	$435	$524

Supplementary_Financial_Statem6

Supplementary Financial Statement Information - Property, Plant and Equipment (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment	$5,871.90	$5,943.90	'
Less accumulated depreciation	-3,991.80	-3,931.60	'
Property, plant and equipment, net	1,880.10	2,012.30	'
Capitalized interest on capital projects	2.7	2.5	6.7
Asset retirement obligations	5.6	5.4	'
Land, land improvements and leaseholds [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment	249.5	239.8	'
Buildings [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment	403.7	428.3	'
Machinery and equipment [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment	5,178	5,224.40	'
Construction in progress [Member]	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'
Property, plant and equipment	$40.70	$51.40	'

Supplementary_Financial_Statem7

Supplementary Financial Statement Information - Other Non-current Assets (Details 6) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Non-current Assets [Abstract]	'	'
Investment in AFSG Holdings, Inc.	$55.60	$55.60
Goodwill	37.1	37.1
Deferred tax assets, non-current	76.6	88.2
Other	95.3	117.2
Other non-current assets	$264.60	$298.10

Investment_in_Equity_Investees

Investment in Equity Investees (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2013	Oct. 04, 2011	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Feb. 21, 2014
In Millions, unless otherwise specified	Combined Metals of Chicago, LLC [Member]	Magnetation LLC [Member]	Magnetation LLC [Member]	Rockport Roll Shop LLC [Member]	Cost of Products Sold [Member]	Cost of Products Sold [Member]	Cost of Products Sold [Member]	Other Income Expense [Member]	Other Income Expense [Member]	Railroad Transportation Equipment [Member]
										Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'	'	'	'	'	'
Equity method investment, ownership percentage (in hundredths)	40.00%	49.90%	'	50.00%	'	'	'	'	'	'
Share of income (loss) from equity method investments	'	'	'	'	$8.10	$7.40	$8.40	($4.90)	$7.70	'
Other Commitment	'	100	297.5	'	'	'	'	'	'	'
Payments to Acquire Equity Method Investments	'	197.5	'	'	'	'	'	'	'	'
Difference between carrying amount and underlying equity	'	96.5	'	'	'	'	'	'	'	'
Property Subject to or Available for Operating Lease, Number of Units	'	'	'	'	'	'	'	'	'	675
Operating Leases, Rent Expense, Minimum Rentals	'	'	'	'	'	'	'	'	'	$4.30
Lessee Leasing Arrangements, Operating Leases, Term of Contract	'	'	'	'	'	'	'	'	'	'15 years

Investments_in_Equity_Investee2

Investments in Equity Investees Equity Investee Summarized Financial Information (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity Method Investment, Summarized Financial Information [Abstract]	'	'	'
Revenue	$293.90	$297.90	$237.50
Gross profit	103.7	92.6	63.2
Net income	20.1	40.8	20.2
Current assets	279.9	97.8	'
Noncurrent assets	440.4	205.5	'
Current liabilities	58.5	23.9	'
Noncurrent liabilities	$397.40	$52.20	'

Investments_in_Equity_Investee3

Investments in Equity Investees Related Party Transactions (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transactions [Abstract]	'	'	'
Sales to equity investees	$71.60	$60.40	$52.80
Purchases from equity investees	12.5	11.8	12.4
Accounts receivable from equity investees	4	2.3	'
Accounts payable to equity investees	0.9	1.1	'
Notes receivable from equity investees	$0	$7.60	'

Income_Taxes_Detail_of_Income_

Income Taxes - Detail of Income (Loss) before Taxes by Geography (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]	'	'	'
United States	($61.10)	($261.20)	($252.50)
Foreign	3.9	6.3	5.7
Noncontrolling interests	64.2	46.3	-7.3
Income (loss) before income taxes	$7	($208.60)	($254.10)

Income_Taxes_Detail_of_Deferre

Income Taxes - Detail of Deferred Tax Assets and Liabilities (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Millions, unless otherwise specified
Deferred tax assets:	'	'	'	'
Net operating loss and tax credit carryforwards	$663.50	$625	'	'
Postretirement benefits	185	231.6	'	'
Pension benefits	216.6	374	'	'
Inventories	118.8	116.7	'	'
Other assets	96.3	94.4	'	'
Valuation allowance	-764.1	-873.1	-22.3	-21.6
Total deferred tax assets	516.1	568.6	'	'
Deferred tax liabilities:	'	'	'	'
Depreciable assets	-333.1	-357.7	'	'
Other liabilities	-36.8	-49.5	'	'
Total deferred tax liabilities	-369.9	-407.2	'	'
Net deferred tax assets	146.2	161.4	'	'
Undistributed earnings of foreign subsidiaries	26.9	'	'	'
Unrecorded tax liability on undistributed earnings of foreign subsidiaries	9.4	'	'	'
Additional Paid-in Capital [Member]	'	'	'	'
Deferred tax liabilities:	'	'	'	'
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward	$21	'	'	'

Income_Taxes_Valuation_Allowan

Income Taxes - Valuation Allowance (Details 3) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Valuation Allowance [Line Items]	'	'	'	'
Valuation Allowance, Deferred Tax Asset, Change in Beginning of the Year Amount	'	($1.60)	$735.20	$0
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'	'
Balance at beginning of year	'	873.1	22.3	21.6
Change in valuation allowance	736	'	'	'
Balance at end of year	'	764.1	873.1	22.3
Included in income tax expense (benefit) [Member]	'	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'	'
Change in valuation allowance	'	21.9	865.5	0.7
Change in deferred assets related to other comprehensive income [Member]	'	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'	'
Change in valuation allowance	'	-130.9	0	0
Included in stockholders' equity related to issuance of exchangeable debt [Member]	'	'	'	'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'	'	'
Change in valuation allowance	'	$0	($14.70)	$0

Income_Taxes_Loss_Carryforward

Income Taxes - Loss Carryforwards (Details 4) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Millions, unless otherwise specified			Internal Revenue Service (IRS) [Member]	Internal Revenue Service (IRS) [Member]	Internal Revenue Service (IRS) [Member]	State and Local Jurisdiction [Member]	Minimum [Member]	Minimum [Member]	Minimum [Member]	Maximum [Member]	Maximum [Member]
			Operating Loss Carryforward [Member]	Alternative Minimum Tax [Member]	Research [Member]	Operating Loss and Tax Credit Carryforwards [Member]	Internal Revenue Service (IRS) [Member]	Internal Revenue Service (IRS) [Member]	State and Local Jurisdiction [Member]	Internal Revenue Service (IRS) [Member]	State and Local Jurisdiction [Member]
								Research [Member]	Operating Loss and Tax Credit Carryforwards [Member]		Operating Loss and Tax Credit Carryforwards [Member]
Tax Credit Carryforward [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Operating Loss Carryforwards	'	'	$1,826.30	$2,207	'	'	'	'	'	'	'
Operating Loss Carryforwards, Expiration Dates	'	'	'	'	'	'	31-Dec-23	'	'	31-Dec-33	'
Tax Credit Carryforward, Amount	'	'	'	20.1	1.2	'	'	'	'	'	'
Tax Credit Carryforward, Expiration Date	'	'	'	'	'	'	'	31-Dec-27	'	'	'
Deferred tax assets from operating loss and tax credit carryforwards	$663.50	$625	'	'	'	$73.30	'	'	'	'	'
Operating Loss and Tax Credit Carryforwards, Expiration Date	'	'	'	'	'	'	'	'	31-Dec-14	'	31-Dec-33

Income_Taxes_Components_of_Inc

Income Taxes - Components of Income Tax Expense (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:	'	'	'
Federal	($3.40)	$0	$0
State	0.2	1	-2.1
Foreign	1.9	1.9	1.8
Noncontrolling interests	0	17.6	-2.8
Deferred:	'	'	'
Federal	14	31.5	-84.9
State	1.2	2.8	-6
Amount allocated to other comprehensive income	-22.7	0	0
Change in valuation allowance on beginning-of-the-year deferred tax assets	-1.6	735.2	0
Income tax expense (benefit)	($10.40)	$790	($94)

Income_Taxes_Effective_Tax_Rat

Income Taxes - Effective Tax Rate Reconciliation (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Reconcilation [Line Items]	'	'	'
Income tax expense (benefit) at U.S. federal statutory rate	$2.40	($73)	($89)
Income tax expense on noncontrolling interest earnings not taxable to the Company	-22.5	0	0
State and foreign tax expense, net of federal tax	1.7	-4.8	-9.9
Increase in deferred tax asset valuation allowance	21.9	865.5	0
Amount allocated to other comprehensive income	-22.7	0	0
Change in accrual for uncertain tax positions	-1.7	0	0
Stock compensation in excess of tax deduction	3.1	0	0
Expiration of charitable contribution carryforwards	2.5	0	0
Other permanent differences	4.9	2.3	2.9
Income tax expense (benefit)	-10.4	790	-94
State and Local Jurisdiction [Member]	'	'	'
Income Tax Reconcilation [Line Items]	'	'	'
Effect of state law changes on deferred tax assets, net of federal tax	$0	$0	$2

Income_Taxes_Unrecognized_Tax_

Income Taxes - Unrecognized Tax Benefits (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits	'	'	'
Balance at beginning of year	$54	$49.20	$50.30
Increases (decreases) for prior year tax positions	-0.8	1.6	1.3
Increases (decreases) for current year tax positions	0.9	3.7	-0.7
Increases (decreases) related to settlements	0	0	-0.2
Decreases related to statute lapse	-0.3	-0.5	-1.5
Balance at end of year	53.8	54	49.2
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	0	'	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	42.6	42.4	'
Unrecognized tax benefits that would result in adjustments to other tax accounts	11.2	11.6	'
Unrecognized tax benefits, accrued interest and penalties	$0.70	$4	'
Internal Revenue Service (IRS) [Member]	'	'	'
Income Tax Contingency [Line Items]	'	'	'
Open Tax Year by Major Tax Jurisdiction	'2010	'	'
State and Local Jurisdiction [Member]	'	'	'
Income Tax Contingency [Line Items]	'	'	'
Open Tax Year by Major Tax Jurisdiction	'2007	'	'

Longterm_Debt_and_Other_Financ2

Long-term Debt and Other Financing Debt Instrument Table (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

Dec. 31, 2012

Dec. 31, 2013

Jun. 30, 2013

Nov. 30, 2012

Dec. 31, 2013

Jun. 24, 2013

Dec. 31, 2012

Nov. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Mar. 30, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Nov. 30, 2012

Dec. 31, 2013

Senior Secured Notes Due December 2018 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Secured Notes Due December 2018 [Member]

Exchangeable Senior Notes Due November 2019 [Member]

Exchangeable Senior Notes Due November 2019 [Member]

Exchangeable Senior Notes Due November 2019 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Senior Notes Due April 2022 [Member]

Senior Notes Due April 2022 [Member]

Senior Notes Due April 2022 [Member]

Unsecured Industrial Revenue Bonds [Member]

Secured Industrial Revenue Bonds [Member]

Industrial Revenue Bonds [Member]

Industrial Revenue Bonds [Member]

Spencer County Bonds [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Debt Instrument, Redemption, Period One [Member]

Debt Instrument, Redemption, Period One [Member]

Debt Instrument, Redemption, Period One [Member]

Debt Instrument, Redemption, Period Two [Member]

Debt Instrument, Redemption, Period Two [Member]

Debt Instrument, Redemption, Period Two [Member]

Debt Instrument, Redemption, Period Three [Member]

Debt Instrument, Redemption, Period Three [Member]

Debt Instrument, Redemption, Period Three [Member]

Debt Instrument, Redemption, Period Four [Member]

Debt Instrument, Redemption, Period Four [Member]

Debt Instrument, Redemption, Period Four [Member]

Debt Instrument, Redemption, Period Five [Member]

Debt Instrument, Redemption, Period Five [Member]

Maximum [Member]

Underwriting Discounts And Other Fees [Member]

Other Income Expense [Member]

Taxable Tax Increment Revenue Bonds Issued [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Senior Secured Notes Due December 2018 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Senior Notes Due May 2020 [Member]

Senior Notes Due April 2022 [Member]

Exchangeable Senior Notes Due November 2019 [Member]

Exchangeable Senior Notes Due November 2019 [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit Facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$90,000,000

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, gross

'

'

'

'

380,000,000

'

350,000,000

'

150,000,000

150,000,000

529,800,000

550,000,000

'

290,200,000

300,000,000

'

73,300,000

26,800,000

100,100,000

100,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized discount/premium, net

-39,000,000

-33,100,000

'

'

'

'

'

'

-34,300,000

-38,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total debt

1,411,900,000

1,507,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current portion of long-term debt

700,000

800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total long-term debt

1,411,200,000

1,506,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

'

350,000,000

'

30,000,000

'

150,000,000

'

'

'

'

'

'

'

300,000,000

'

'

'

'

23,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Interest Rate, Stated Percentage (in hundredths)

'

'

'

8.75%

8.75%

'

'

5.00%

'

'

7.63%

'

'

'

'

8.38%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Maturity Date

'

'

'

'

1-Dec-18

'

'

'

15-Nov-19

'

15-May-20

'

'

1-Apr-22

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from Debt, Net of Issuance Costs

'

'

30,900,000

341,100,000

'

'

'

144,800,000

'

'

'

'

293,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument Offering Price

'

'

106.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets Pledged as Collateral, Carrying Amount

'

'

'

'

1,400,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Maturity Date Range, Start

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Dec-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Maturity Date Range, End

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Dec-30

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Redemption, Description

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Prior to DecemberB 1, 2015, AK Steel may redeem the Secured Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption.

'Prior to May 15, 2015, AK Steel may redeem the 2020 Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption.

'Prior to April 1, 2017, AK Steel may redeem the 2022 Notes at a price equal to par plus a make-whole premium and all accrued and unpaid interest to the date of redemption.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Redemption Price Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

104.38%

103.81%

104.19%

102.19%

102.54%

102.79%

100.00%

101.27%

101.40%

100.00%

100.00%

'

'

'

Debt Instrument, Redemption Period, Start Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-Dec-15

15-May-15

1-Apr-17

1-Dec-16

15-May-16

1-Apr-18

1-Dec-17

15-May-17

1-Apr-19

15-May-18

1-Apr-20

'

'

'

Debt Instrument, Redemption Period, End Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Nov-15

14-May-15

31-Mar-17

30-Nov-16

14-May-16

31-Mar-18

30-Nov-17

14-May-17

31-Mar-19

30-Nov-18

14-May-18

31-Mar-20

14-May-20

31-Mar-22

'

'

'

Debt Instrument, Repurchased Face Amount

'

'

'

'

'

'

'

'

'

'

20,200,000

'

'

9,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gain (Loss) on Repurchase of Debt Instrument

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,900,000

Long-term Debt, Weighted Average Interest Rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.80%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Effective Interest Rate

'

'

'

'

'

'

'

'

10.80%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Conversion Ratio (in shares per $1,000 principal amount)

'

'

'

'

'

'

'

'

185.1852

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Conversion Price (in dollars per share)

'

'

'

'

'

'

'

'

$5.40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Number of Equity Instruments Used to Determine Consideration to Be Delivered Upon Conversion (in shares)

'

'

'

'

'

'

'

'

27,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, Number Of Equity Instruments (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

37,500,000

'

'

Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt

37,300,000

'

'

'

'

'

'

38,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-1,400,000

'

Debt Instrument, Convertible, Carrying Amount of Equity Component

'

'

'

'

'

'

'

'

37,300,000

37,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Convertible, If-converted Value in Excess of Principal

'

'

'

'

'

'

'

'

35,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Carrying Value of Long-term Debt

'

'

'

'

'

'

'

'

115,700,000

111,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deficiency Payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term Debt Maturities, Repayments of Principal and Interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$24,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Longterm_Debt_and_Other_Financ3

Long-term Debt and Other Financing Debt Maturities (Details 2) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Maturities of Long-term Debt [Abstract]	'
2014 debt maturities	$0.80
2015 debt maturities	0
2016 debt maturities	90
2017 debt maturities	0
2018 debt maturities	$380

Credit_Facility_and_Other_Fina

Credit Facility and Other Financing Information (Details 3) (Revolving Credit Facility [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Revolving Credit Facility [Member]	'	'
Line of Credit Facility [Line Items]	'	'
Line of credit facility, maximum borrowing capacity	$1,100,000,000	'
Line of credit facility, expiration date	28-Apr-16	'
Minimum amount of borrowing capacity before a fixed charge coverage ratio applies	137,500,000	'
Line of credit, current borrowing capacity based on eligible collateral	972,100,000	'
Current borrowings on credit facility	90,000,000	0
Letters of credit, outstanding	67,100,000	'
Line of credit facility, remaining borrowing capacity	$815,000,000	'
Debt Instrument, Covenant Description	'The Credit Facility contains common restrictions, including limitations on, among other things, distributions and dividends, acquisitions and investments, indebtedness, liens and affiliate transactions. Availability is calculated as the lesser of the credit facility commitment or the Companybs eligible collateral after advance rates, less outstanding revolver borrowings and letters of credit. The Companybs obligation under its Credit Facility is secured by its inventory and accounts receivable and availability under the Credit Facility fluctuates monthly based on the varying levels of eligible collateral. In addition, the Credit Facility requires maintenance of a minimum fixed charge coverage ratio of one to one if availability under the Credit Facility is less than $137.5.	'
Line of credit facility, Weighted Average Interest Rate (in hundredths)	2.20%	'

Pension_and_Other_Postretireme2

Pension and Other Postretirement Benefits (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Jan. 31, 2014

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Pension Plans, Defined Benefit [Member]

Pension Plans, Defined Benefit [Member]

Pension Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Subsequent Event [Member]

Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Pension Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Defined Benefit Plan Disclosure [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future pension contributions 2014

'

'

'

$205

'

'

'

'

'

'

'

'

'

'

Contributions to pension trust

181.1

170.2

170

'

'

'

'

'

'

'

41.3

'

'

'

Defined Benefit Plans, Estimated Future Employer Contributions, Year Two

'

'

'

105

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plans, Estimated Future Employer Contributions, Year Three

'

'

'

65

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months

'

'

'

'

'

'

65.3

'

'

'

'

'

'

'

Amount of cash contributions to the VEBA trust in the next fiscal year following the latest fiscal year

'

'

'

'

'

'

'

'

'

'

'

3.1

'

'

Change in benefit obligations:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Benefit obligations at beginning of year

'

'

'

3,759.40

3,539.50

'

602

713.2

'

'

'

'

'

'

Service cost

'

'

'

2.4

3.2

3.2

4.7

4.6

4.2

'

'

'

'

'

Interest cost

'

'

'

138.8

160.2

180.8

21

31.5

37.9

'

'

'

'

'

Plan participants' contributions

'

'

'

0

0

'

27

28.9

'

'

'

'

'

'

Actuarial loss (gain)

'

'

'

-214.8

364.2

'

-54.3

35.9

'

'

'

'

'

'

Amendments

'

'

'

6

3.5

'

0

-87.4

'

3

'

'

'

'

Contributions to Butler and Zanesville retirees' VEBA trusts

'

'

'

0

0

'

'

'

'

'

'

'

-30.8

-31.7

Benefits paid

'

'

'

-311.4

-311.3

'

-95.6

-101.4

'

'

'

'

'

'

Medicare subsidy reimbursement received

'

'

'

0

0

'

5.2

8.4

'

'

'

'

'

'

Foreign currency exchange rate changes

'

'

'

0.2

0.1

'

0

0

'

'

'

'

'

'

Benefit obligations at end of year

'

'

'

3,380.60

3,759.40

3,539.50

479.2

602

713.2

'

'

'

'

'

Change in plan assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of plan assets at beginning of year

'

'

'

2,591.10

2,377.90

'

0

0

'

'

'

'

'

'

Actual gain on plan assets

'

'

'

337.7

347.8

'

0

0

'

'

'

'

'

'

Employer contributions

'

'

'

191.1

176.7

'

63.4

64.1

'

'

'

'

'

'

Plan participants' contributions

'

'

'

0

0

'

27

28.9

'

'

'

'

'

'

Benefits paid

'

'

'

-311.4

-311.3

'

-95.6

-101.4

'

'

'

'

'

'

Medicare subsidy reimbursement received

'

'

'

0

0

'

5.2

8.4

'

'

'

'

'

'

Fair value of plan assets at end of year

'

'

'

2,808.50

2,591.10

2,377.90

0

0

0

'

'

'

'

'

Funded status

'

'

'

-572.1

-1,168.30

'

-479.2

-602

'

'

'

'

'

'

Amounts recognized in the consolidated balance sheets:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current liabilities

-85.9

-108.6

'

-17.5

-5.7

'

-68.4

-102.9

'

'

'

'

'

'

Noncurrent liabilities

-965.4

-1,661.70

'

-554.6

-1,162.60

'

-410.8

-499.1

'

'

'

'

'

'

Net amount recognized

'

'

'

-572.1

-1,168.30

'

-479.2

-602

'

'

'

'

'

'

Amounts recognized in accumulated other comprehensive income, before tax:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Actuarial loss (gain)

'

'

'

-16.7

374.2

'

-19.8

36.8

'

'

'

'

'

'

Prior service cost (credit)

'

'

'

18.5

16.3

'

-318.4

-398.4

'

'

'

'

'

'

Net amount recognized

'

'

'

1.8

390.5

'

-338.2

-361.6

'

'

'

'

'

'

Aggregate accumulated benefit obligation

'

'

'

$3,362.10

$3,740.50

'

'

'

'

'

'

'

'

'

Pension_and_Other_Postretireme3

Pension and Other Postretirement Benefits - Assumptions (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]	'	'	'
Assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.53%	3.85%	4.74%
Rate of compensation increase	4.00%	4.00%	4.00%
Assumptions used to determine pension and OPEB expense (income) for the year ended December 31:	'	'	'
Discount rate	3.85%	4.74%	5.36%
Expected return on plan assets	7.25%	8.00%	8.50%
Rate of compensation increase	4.00%	4.00%	4.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'	'
Assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.48%	3.77%	4.72%
Rate of compensation increase	4.00%	4.00%	4.00%
Subsequent year healthcare cost trend rate	7.00%	7.50%	7.50%
Ultimate healthcare cost trend rate	4.50%	4.50%	4.50%
Year ultimate healthcare cost trend rate begins	'2019	'2019	'2018
Assumptions used to determine pension and OPEB expense (income) for the year ended December 31:	'	'	'
Discount rate	3.77%	4.72%	5.18%
Rate of compensation increase	4.00%	4.00%	4.00%
Effect of one percentage point increase on total service and interest cost components	0.1	'	'
Effect of one percentage point decrease on total service and interest cost components	-0.1	'	'
Effect of one percentage point increase on postretirement benefit obligation	3.3	'	'
Effect of one percentage point decrease on postretirement benefit obligation	-3.2	'	'

Pension_and_Other_Postretireme4

Pension and Other Postretirement Benefits - Expected Benefit Payments (Details 3) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Pension Plans, Defined Benefit [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
Expected Future Benefit Payments in 2014	$315.60
Expected Future Benefit Payments in 2015	299.1
Expected Future Benefit Payments in 2016	281.5
Expected Future Benefit Payments in 2017	299
Expected Future Benefit Payments in 2018	261.1
Expected Future Benefit Payments in 2019 through 2023	1,179.50
Other Postretirement Benefit Plans, Defined Benefit [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
Expected Future Benefit Payments in 2014	70.7	[1]
Expected Future Benefit Payments in 2015	49.3	[1]
Expected Future Benefit Payments in 2016	44.6	[1]
Expected Future Benefit Payments in 2017	41.9	[1]
Expected Future Benefit Payments in 2018	39.8	[1]
Expected Future Benefit Payments in 2019 through 2023	171.8	[1]
Expected Medicare Subsidy Receipts in 2014	-5.4	[1]
Expected Medicare Subsidy Receipts in 2015	-3.7	[1]
Expected Medicare Subsidy Receipts in 2016	-3.4	[1]
Expected Medicare Subsidy Receipts in 2017	-3.4	[1]
Expected Medicare Subsidy Receipts in 2018	-3.3	[1]
Expected Medicare Subsidy Receipts in 2019 through 2023	($15.90)	[1]
[1]	The amounts shown do not include the lump sum payments to the VEBA trust related to the Zanesville Retiree Settlement. These amounts reflect the fact that the Company will have eliminated its OPEB liability related to the group of retirees covered by the Butler Retiree Settlement after 2014 and the Zanesville Retiree Settlement after 2015.

Pension_and_Other_Postretireme5

Pension and Other Postretirement Benefits - Plan Assets (Details 4) (Pension Plans, Defined Benefit [Member], USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

Equity Securities [Member]

Fixed Income Securities [Member]

Cash and Cash Equivalents [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

US Equity Securities [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

U.S. Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

EAFE Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Emerging Market Equity Securities Common/Collective Trusts [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

Global Equity Investments [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Investment-Grade Corporate Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

U.S. Treasuries Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Mortgage-Backed Fixed Income Investments Common/Collective Trusts [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

Global Fixed Income Investments [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

U.S. High-Yield Corporate Fixed Income Securities [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Private Equity Funds [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 3 [Member]

Fair Value, Inputs, Level 3 [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of plan assets

$2,808.50

$2,591.10

$2,377.90

'

'

'

'

'

$2,808.50

$2,591.10

$301.50

$219

$2,506.40

$2,368.90

$0.60

$3.20

$45.50

$50

$45.50

$50

$0

$0

$0

$0

$176.60

$108.10

$176.60

$108.10

$0

$0

$0

$0

$840.50

$808.30

$0

$0

$840.50

$808.30

$0

$0

$277.60

$256.80

$0

$0

$277.60

$256.80

$0

$0

$79.40

$60.90

$79.40

$60.90

$0

$0

$0

$0

$128.10

$134.70

$0

$0

$128.10

$134.70

$0

$0

$230.80

$187.10

$0

$0

$230.80

$187.10

$0

$0

$378.40

$333.40

$0

$0

$378.40

$333.40

$0

$0

$88.10

$98.40

$0

$0

$88.10

$98.40

$0

$0

$20.50

$15.60

$0

$0

$20.50

$15.60

$0

$0

$350.80

$359.60

$0

$0

$350.80

$359.60

$0

$0

$191.60

$175

$0

$0

$191.60

$175

$0

$0

$0.60

[1]

$3.20

[1]

$0

$0

$0

$0

$0.60

[1]

$3.20

[1]

Level 3 Assets [Roll Forward]

'

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Beginning of year

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3.2

2.5

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Unrealized gains

'

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1.3

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Distribution to master pension trust

'

'

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-2.6

-0.6

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End of year

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$0.60

$3.20

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Defined Benefit Plan, Target Allocation, Percentages of Assets [Abstract]

'

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Target plan asset allocations percentage

'

'

'

60.00%

38.00%

2.00%

'

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[1]

Consists of private equity funds that have no remaining capital commitments due from the Company.

Pension_and_Other_Postretireme6

Pension and Other Postretirement Benefits - Benefit Costs (Details 5) (USD $)

3 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

36 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jul. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2011

Pension Plans, Defined Benefit [Member]

Pension Plans, Defined Benefit [Member]

Pension Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Butler and Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Zanesville Works Retiree Healthcare Benefits Litigation [Member]

Butler Works Retiree Healthcare Benefits Litigation [Member]

Butler Works Retiree Healthcare Benefits Litigation [Member]

Middletown Retirees [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Other Postretirement Benefit Plans, Defined Benefit [Member]

Components of pension and OPEB expense (income):

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Service cost

'

'

'

'

$2.40

$3.20

$3.20

$4.70

$4.60

$4.20

'

'

'

'

'

'

'

'

'

Interest cost

'

'

'

'

138.8

160.2

180.8

21

31.5

37.9

'

'

'

'

'

'

'

'

'

Expected return on plan assets

'

'

'

'

-184.5

-188.3

-207.5

0

0

0

'

'

'

'

'

'

'

'

'

Amortization of prior service cost (credit)

'

'

'

'

3.8

3.8

4

-80

-77.4

-76.6

'

'

'

'

'

'

'

'

'

Reversal of prior amortization related to Zanesville and Butler Retiree Settlements

'

'

'

'

0

0

0

'

'

'

0

2.5

14.2

'

'

'

'

'

'

Recognized net actuarial loss (gain):

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual amortization

'

'

'

'

23.6

24.5

18.8

2.4

0.1

-1

'

'

'

'

'

'

'

'

'

Pension corridor charge

157.3

0

157.3

268.1

0

157.3

268.1

0

0

0

'

'

'

'

'

'

'

'

'

Settlement gain

'

'

'

'

-0.8

0

0

0

0

'

'

'

'

'

'

'

'

'

-14

Pension and OPEB expense (income)

'

'

'

'

-16.7

160.7

267.4

-51.9

-38.7

-35.3

'

'

'

'

'

'

'

'

'

Amount of combined lump sum payments to VEBA and plaintiff's counsel

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.6

'

'

'

'

Payments for Legal Settlements

'

'

'

'

'

'

'

'

'

'

'

'

'

4.4

'

'

'

91

'

Increase in benefit obligation from litigation settlement

'

'

'

'

6

3.5

'

0

-87.4

'

'

'

'

'

'

3

29.6

'

'

Reversal of Prior Amortization Related to Retiree Settlement and Legal Fees

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.8

'

'

'

Estimated net loss (gain) expected to be amortized into pension and OPEB expense (income) in the next year

'

'

'

'

-4.1

'

'

-1.3

'

'

'

'

'

'

'

'

'

'

'

Estimated net prior service cost (credit) expected to be amortized into pension and OPEB expense (income) in the next year

'

'

'

'

4.2

'

'

-73.2

'

'

'

'

'

'

'

'

'

'

'

Expense for defined contribution plans

'

$11.50

$11.60

$12.40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pension_and_Other_Postretireme7

Pension and Other Postretirement Benefits - Multiemployer Plans (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	employees
Multiemployer Plans [Line Items]	'	'	'
Contributions to multiemployer plans	$22.10	$19.60	$20
Number of Employees	6,400	'	'
Steelworkers Pension Trust [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Contributions to multiemployer plans	7.3	7	7.2
IAM National Pension Fund's National Pension Plan [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Contributions to multiemployer plans	14.8	12.6	12.3
Multiemployer Plan, Individually Insignificant Multiemployer Plans [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Contributions to multiemployer plans	0	0	0.5
Walbridge Tube [Member] | Steelworkers Pension Trust [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	90	'	'
Ashland Works [Member] | Steelworkers Pension Trust [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	820	'	'
Zanesville Works [Member] | IAM National Pension Fund's National Pension Plan [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	160	'	'
Butler Works [Member] | IAM National Pension Fund's National Pension Plan [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	1,200	'	'
Ashland coke plant [Member] | PACE Industry Union-Management Pension Fund [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Multiemployer Plans Withdrawal Obligation	'	$1.80	'
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member] | Mansfield Works [Member] | Steelworkers Pension Trust [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	280	'	'
Workforce Subject to Collective Bargaining Arrangements Expiring within One Year [Member] | Middletown Works [Member] | IAM National Pension Fund's National Pension Plan [Member]	'	'	'
Multiemployer Plans [Line Items]	'	'	'
Number of Employees	1,650	'	'

Operating_Leases_Details

Operating Leases (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Leases [Abstract]	'	'	'
Rental Expense	$27	$28	$24.70
Minimum Lease Payments 2014	8.9	'	'
Minimum Lease Payments 2015	7.1	'	'
Minimum Lease Payments 2016	5	'	'
Minimum Lease Payments 2017	4.7	'	'
Minimum Lease Payments 2018	4.3	'	'
Minimum Lease Payments 2019 and thereafter	7.3	'	'
Total minimum lease payments	$37.30	'	'
Description of Lessee Leasing Arrangements, Operating Leases	'The initial term of the lease for the building expires in 2019 and there are two five-year options to extend the lease.	'	'

Commitments_Details

Commitments (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
	T
SunCoke Energy, Inc. [Member]	'
Long-term Purchase Commitment [Line Items]	'
Long-term annual purchase commitment for coke (in tons)	1,100,000
Capital Investment Commitments [Member]	'
Long-term Purchase Commitment [Line Items]	'
Commitments for future capital investments	24.1

Environmental_and_Legal_Contin2

Environmental and Legal Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]	'	'	'
Environmental-related capital investments	$1.60	$1	$1.70
Environmental compliance costs	$101.10	$101.60	$106.40

Environmental_and_Legal_Contin3

Environmental and Legal Contingencies (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Other Current Liabilities [Member]	'	'
Accrued liabilities	$9.50	$19.60
Other Noncurrent Liabilities [Member]	'	'
Other non-current liabilities	$34.10	$27.40

Environmental_and_Legal_Contin4

Environmental and Legal Contingencies (Details 3) (USD $)	Dec. 31, 2013	Dec. 31, 2013	Oct. 17, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Millions, unless otherwise specified	Hamilton Plant [Member]	Mansfield Works [Member]	Mansfield Works [Member]	Ashland coke plant [Member]	Ambridge Works [Member]	Dicks Creek [Member]	Capital Addition Purchase Commitments [Member]
							Ashland coke plant [Member]
Site Contingency [Line Items]	'	'	'	'	'	'	'
Site contingency accrual, undiscounted amount	$0.70	$1.10	'	$0.50	$2.20	$13.90	'
Accrual for Environmental Loss Contingencies, Payments	'	'	'	1.7	'	'	'
Other Commitment	'	'	'	'	'	'	2
Proposed civil penalty related to environmental issue	'	'	$0.30	'	'	'	'

Environmental_and_Legal_Contin5

Environmental and Legal Contingencies (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2013
	plaintiffs
	defendants
	claims-lawsuits
Asbestos Claims With Specific Dollar Claim For Damages [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	131	[1]
Claims with specific dollar claims for damages [Abstract]	'
Asbestos Lawsuits Pending With Dollars Number Of Plaintiffs	2,387
Asbestos Lawsuits Pending With Dollars Number Of Defendants	17,623
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos claims up to $0.2 [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	121
Claims with specific dollar claims for damages [Abstract]	'
Asbestos Lawsuits Pending With Dollars Lower Range	0
Asbestos Lawsuits Pending With Dollars Upper Range	200,000
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos claims above $0.2 to $5.0 [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	6
Claims with specific dollar claims for damages [Abstract]	'
Asbestos Lawsuits Pending With Dollars Lower Range	200,000
Asbestos Lawsuits Pending With Dollars Upper Range	5,000,000
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos claims above $5.0 to $15.0 [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	2
Claims with specific dollar claims for damages [Abstract]	'
Asbestos Lawsuits Pending With Dollars Lower Range	5,000,000
Asbestos Lawsuits Pending With Dollars Upper Range	15,000,000
Asbestos Claims With Specific Dollar Claim For Damages [Member] | Asbestos claims above $15.0 to $20.0 [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	2
Claims with specific dollar claims for damages [Abstract]	'
Asbestos Lawsuits Pending With Dollars Lower Range	15,000,000
Asbestos Lawsuits Pending With Dollars Upper Range	20,000,000
Asbestos Claims Without Specific Dollar Claim For Damages [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	305
Asbestos Issue [Member]	'
Information on pending asbestos cases [Line Items]	'
Total asbestos cases pending	436
[1]	Involve a total of 2,387 plaintiffs and 17,623 defendants

Environmental_and_Legal_Contin6

Environmental and Legal Contingencies (Details 5) (Asbestos Issue [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	claims-lawsuits	claims-lawsuits	claims-lawsuits
Asbestos Issue [Member]	'	'	'
Loss Contingency, Claims Quantities [Abstract]	'	'	'
New Claims Filed	42	50	31
Pending Claims Disposed Of	39	24	44
Total Amount Paid in Settlements	$1	$0.80	$0.70

Environmental_and_Legal_Contin7

Environmental and Legal Contingencies (Details 6) (USD $)

1 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

In Millions, unless otherwise specified

Oct. 31, 2009

Aug. 26, 2009

Jul. 31, 2013

Jul. 31, 2013

Jul. 31, 2013

Jul. 31, 2013

Oct. 14, 2013

Nov. 13, 2013

29-May-13

Nov. 23, 2013

Nov. 23, 2013

Oct. 14, 2013

Nov. 23, 2013

Schumacher [Member]

Consolidation Coal [Member]

Final [Member]

Final [Member]

Final [Member]

Preliminary [Member]

Preliminary [Member]

Final [Member]

Final [Member]

Final [Member]

Final [Member]

Final [Member]

Final [Member]

plaintiffs

MOFCOM [Member]

Countervailing Duty [Member]

Antidumping Duty [Member]

Countervailing Duty [Member]

Attorneys [Member]

Schumacher [Member]

Schumacher [Member]

Patrick [Member]

Plaintiffs And Other Class Members [Member]

Attorneys [Member]

Attorneys [Member]

MOFCOM [Member]

MOFCOM [Member]

MOFCOM [Member]

Schumacher [Member]

Patrick [Member]

Schumacher [Member]

Patrick [Member]

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss Contingency, Number of Plaintiffs

92

'

'

'

'

'

'

'

'

'

'

'

'

Potential exposure of increase to defined benefit plan obligation

'

'

'

'

'

'

$1.30

$4.40

$3

'

'

$0.60

'

Total Amount Paid in Settlements

'

'

'

'

'

'

'

'

'

2.5

1.7

'

0.8

Loss contingency, damages sought, value

'

30

'

'

'

'

'

'

'

'

'

'

'

Loss contingency, damages sought, value, codefendant

'

$20

'

'

'

'

'

'

'

'

'

'

'

Duty Rate

'

'

11.20%

3.40%

7.80%

11.70%

'

'

'

'

'

'

'

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	1 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Nov. 30, 2012	Oct. 31, 2008	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 20, 2012
Summary of Stockholders' Equity Disclosure [Line Items]	'	'	'	'	'	'
Preferred stock authorized (in shares)	'	'	25,000,000	'	'	'
Preferred stock issued (in shares)	'	'	0	'	'	'
Preferred stock outstanding (in shares)	'	'	0	'	'	'
Stock Issued During Period, Shares, New Issues (in shares)	25,300,000	'	'	'	'	'
Share Price	'	'	'	'	'	$4
Proceeds from issuance of common stock	$96.40	'	$0	$96.40	$0	'
Stock Repurchase Program, Authorized Amount	'	150	'	'	'	'
Stock Repurchase Program, Remaining Authorized Repurchase Amount	'	'	125.6	'	'	'
Line of Credit Facility, Dividend Restrictions	'	'	'The Companybs Credit Facility contains certain restrictive covenants with respect to the Companybs payment of dividends. Under these covenants, dividends are permitted provided (i) availability exceeds $247.5 or (ii) availability exceeds $192.5 and the Company meets a fixed charge coverage ratio of one to one as of the most recently ended fiscal quarter. If the Company cannot meet either of these thresholds, dividends would be limited to $12.0 annually.	'	'	'
Revolving Credit Facility [Member]	'	'	'	'	'	'
Summary of Stockholders' Equity Disclosure [Line Items]	'	'	'	'	'	'
Amount Of Threshold Under Credit Facility, Dividend Restriction, Unlimited	'	'	247.5	'	'	'
Amount Of Threshold Under Credit Facility, Dividend Restriction, Unlimited with Financial Covenant Compliance	'	'	192.5	'	'	'
Availability under credit facility exceeds	'	'	247.5	'	'	'
Maximum [Member] | Revolving Credit Facility [Member]	'	'	'	'	'	'
Summary of Stockholders' Equity Disclosure [Line Items]	'	'	'	'	'	'
Dividends would be limited to this amount annually	'	'	$12	'	'	'

Sharebased_Compensation_Detail

Share-based Compensation (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Maximum issuable shares under Stock Incentive Plan	19,000,000	'	'
Shares available for future grant under Stock Incentive Plan	3,000,000	'	'
Share-based Compensation Expense [Abstract]	'	'	'
Share-based Compensation Expense	$9.50	$14.60	$14.90
Stock Options [Member]	'	'	'
Share-based Compensation Expense [Abstract]	'	'	'
Share-based Compensation Expense	1.5	2.4	2.3
Maximum term of stock option awards (in number of years)	'10 years	'	'
Minimum vesting period for stock option awards (in number of months)	'6 months	'	'
Share based compensation estimated to be forfeited (in hundredths)	5.00%	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]	'	'	'
Expected volatility, minimum (in hundredths)	57.80%	63.20%	59.70%
Expected volatility, maximum (in hundredths)	68.80%	73.20%	78.00%
Weighted-average volatility (in hundredths)	65.20%	69.40%	62.10%
Risk-free interest rate, minimum (in hundredths)	0.40%	0.30%	0.40%
Risk-free interest rate, maximum (in hundredths)	1.10%	1.20%	2.60%
Dividend yield (in hundredths)	0.00%	2.20%	1.40%
Weighted-average grant-date fair value per share of options granted	$2.44	$4.31	$6.83
Summary of changes in shares outstanding under all long-term incentive plans [Rollforward]	'	'	'
Number of options outstanding, beginning balance (in shares)	1,819,382	'	'
Number of options granted (in shares)	502,750	'	'
Number of options exercised (in shares)	-15,000	'	'
Number of options canceled (in shares)	-113,600	'	'
Number of options outstanding, ending balance (in shares)	2,193,532	1,819,382	'
Number of exercisable options (in shares)	1,283,599	'	'
Number of unvested options (in shares)	909,933	'	'
Number of unvested options that are expected to vest (in shares)	864,436	'	'
Weighted average exercise price per option, outstanding, beginning of period (dollars per share)	$14.46	'	'
Weighted average exercise price per option granted (dollars per share)	$4.58	'	'
Weighted average exercise price per option exercised (dollars per share)	$4.57	'	'
Weighted average exercise price per option canceled (dollars per share)	$14.64	'	'
Weighted average exercise price per option, outstanding, end of period (dollars per share)	$12.26	$14.46	'
Weighted average exercise price per exercisable option (dollars per share)	$15.85	'	'
Weighted average exercise price per unvested options (dollars per share)	$7.19	'	'
Weighted average exercise price per unvested options that expected to vest (dollars per share)	$7.19	'	'
Remaining average contractual life of options outstanding (in years)	'5 years 11 months	'	'
Remaining average contractual life of options exercisable (in years)	'4 years 8 months	'	'
Remaining average contractual life of unvested options (in years)	'7 years 8 months	'	'
Remaining average contractual life of unvested options that are expected to vest (in years)	'7 years 8 months	'	'
Aggregate intrinsic value of options outstanding, outstanding	1.9	'	'
Aggregate intrinsic value of options outstanding, exercisable	0.1	'	'
Aggregate intrinsic value of options outstanding, unvested	1.8	'	'
Aggregate intrinsic value of options outstanding, unvested and expected to vest	1.7	'	'
Intrinsic value of options exercised	0	0	0.2
Amount of unrecognized compensation costs	0.4	'	'
Weighted average period of recognition (in years)	'1 year 7 months	'	'
Restricted Stock [Member]	'	'	'
Share-based Compensation Expense [Abstract]	'	'	'
Share-based Compensation Expense	2.9	5.3	5.9
Summary of changes in shares outstanding under all long-term incentive plans [Rollforward]	'	'	'
Intrinsic value of shares vested/restrictions lapsed during the period	2.1	4.9	4.4
Amount of unrecognized compensation costs	1.3	'	'
Weighted average period of recognition (in years)	'1 year 8 months	'	'
Summary of nonvested shares [Roll Forward]	'	'	'
Nonvested, beginning of period (in shares)	398,113	'	'
Granted (in shares)	550,581	'	'
Vested/restrictions lapsed/earned (in shares)	-466,641	'	'
Canceled (in shares)	-48,824	'	'
Nonvested, end of period (in shares)	433,229	398,113	'
Weighted average grant date fair value, nonvested, beginning of period (dollars per share)	$11.33	'	'
Weighted average grant date fair value, granted (dollars per share)	$4.43	$8.78	$14.47
Weighted average grant date fair value, vested/restrictions lapsed/earned (dollars per share)	$8.14	'	'
Weighted average grant date fair value, canceled (dollars per share)	$8.02	'	'
Weighted average grant date fair value, nonvested, end of period (dollars per share)	$6.35	$11.33	'
Restricted Stock Units Issued to Directors [Member]	'	'	'
Share-based Compensation Expense [Abstract]	'	'	'
Share-based Compensation Expense	1	0.9	0.9
Performance Share Awards [Member]	'	'	'
Share-based Compensation Expense [Abstract]	'	'	'
Share-based Compensation Expense	4.1	6	5.8
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]	'	'	'
Weighted-average volatility (in hundredths)	59.20%	69.40%	89.00%
Weighted-average volatility S&P MidCap 400 Index (in hundredths)	34.70%	42.20%	52.40%
Risk-free interest rate (in hundredths)	0.40%	0.40%	1.00%
Dividend yield (in hundredths)	0.00%	2.20%	1.40%
Summary of changes in shares outstanding under all long-term incentive plans [Rollforward]	'	'	'
Amount of unrecognized compensation costs	$3.40	'	'
Weighted average period of recognition (in years)	'1 year 6 months	'	'
Summary of nonvested shares [Roll Forward]	'	'	'
Nonvested, beginning of period (in shares)	942,313	'	'
Granted (in shares)	585,450	'	'
Vested/restrictions lapsed/earned (in shares)	0	'	'
Canceled (in shares)	-474,990	'	'
Nonvested, end of period (in shares)	1,052,773	942,313	'
Weighted average grant date fair value, nonvested, beginning of period (dollars per share)	$12.24	'	'
Weighted average grant date fair value, granted (dollars per share)	$4.68	$9.89	$15.78
Weighted average grant date fair value, vested/restrictions lapsed/earned (dollars per share)	$0	'	'
Weighted average grant date fair value, canceled (dollars per share)	$14.02	'	'
Weighted average grant date fair value, nonvested, end of period (dollars per share)	$7.23	$12.24	'
Minimum [Member] | Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]	'	'	'
Expected term (in years)	'2 years 9 months	'2 years 7 months	'2 years 7 months
Maximum [Member] | Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]	'	'	'
Expected term (in years)	'6 years 4 months	'6 years 3 months	'6 years 3 months

Comprehensive_Income_Loss_Deta

Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Foreign currency translation	'		'		'
Balance at beginning of period	$3.50		'		'
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]	'		'		'
Foreign currency translation gain (loss)	1.2		0.7		-0.7
Balance at end of period	4.7		3.5		'
Cash flow hedges	'		'		'
Balance at beginning of period	31.7		'		'
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]	'		'		'
Gains (losses) arising in period	3.5		6.3		-21
Income tax expense (benefit)	1.3		'		-8
Gains (losses) arising in period, net of tax	2.2		'		'
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax [Abstract]	'		'		'
Reclassification of losses (gains) to net income (loss)	-25.2		36.3		4
Income tax (expense) benefit	-9.6	[1]	'		1.5
Net amount of reclassification of losses (gains) to net income (loss)	15.6		'		'
Total other comprehensive income (loss), (Derivatives Qualifying as Hedges), net of tax	-13.4		'		'
Balance at end of period	18.3		31.7		'
Unrealized holding gains (losses) on securities	'		'		'
Balance at beginning of period	0.3		'		'
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]	'		'		'
Unrealized holding gains (losses) arising in period	0.2		0.9		-0.5
Income tax expense (benefit)	0.1		'		-0.2
Unrealized holding gains (losses) arising in period, net of tax	0.1		'		'
Balance at end of period	0.4		0.3		'
Pension and OPEB Plans	'		'		'
Balance at beginning of period	-34.4		'		'
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]	'		'		'
Prior service credit (cost) arising in period	-6.1		83.9		-20.6
Gains (losses) arising in period	422.3		-240.4		-319.4
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax	416.2		'		'
Income tax expense (benefit)	50.3		'		'
Gains (losses) arising in period, net of tax	365.9		'		'
Other Comprehensive Income (Loss), Reclassification Adjustment, Pension and Other Postretirement Benefit Plans, Included in Net Income, before Tax [Abstract]	'		'		'
Reclassification of prior service cost (credits) included in net income (loss)	-76.2	[2]	-71.1	[2]	-58.5	[2]
Reclassification of actuarial (gains) losses included in net income (loss)	25.3	[2]	181.8	[2]	272	[2]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax	-50.9		'		'
Income tax (expense) benefit	-19.4	[1]	'		'
Amount of reclassification to net income (loss), net of tax	-31.5		'		'
Total other comprehensive income (loss), net of tax	334.4		'		'
Balance at end of period	300		-34.4		'
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]	'		'		'
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax [Abstract]	'		'		'
Reclassification of losses (gains) to net income (loss)	-25.2		'		'
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Sales [Member] | Hot roll carbon steel coils [Member]	'		'		'
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax [Abstract]	'		'		'
Reclassification of losses (gains) to net income (loss)	-0.4	[3]	'		'
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member] | Cost of Products Sold [Member] | Other Commodity Contracts [Member]	'		'		'
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax [Abstract]	'		'		'
Reclassification of losses (gains) to net income (loss)	($24.80)	[4]	'		'
[1]	Amounts are included in income tax expense (benefit) on the Consolidated Statements of Operations.
[2]	Amounts are included in pension and OPEB expense (income) on the Consolidated Statements of Operations.
[3]	Amounts are included in net sales on the Consolidated Statements of Operations.
[4]	Amounts are included in cost of products sold on the Consolidated Statements of Operations.

Comprehensive_Income_Loss_Sche

Comprehensive Income (Loss) Schedule of Tax Effects Allocated to Each Component of Other Comprehensive Income Loss (Details2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Cash flow hedges:	'		'	'
Gains (losses) arising in period	$1.30		'	($8)
Reclassification of loss (gain) to net income (loss)	-9.6	[1]	'	1.5
Unrealized holding gain (loss) on securities:	'		'	'
Unrealized holding gain (loss) arising in period	0.1		'	-0.2
Pension and OPEB plans:	'		'	'
Prior service cost arising in period	'		'	-7.5
Reclassification of prior service cost (credits) included in net income (loss)	'		'	-22.3
Gains (losses) arising in period	'		'	-122.2
Reclassification of losses (gains) included in net income (loss)	'		'	103.9
Income tax expense (benefit) related to items of other comprehensive income (loss)	$22.70		$0	($54.80)
[1]	Amounts are included in income tax expense (benefit) on the Consolidated Statements of Operations.

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net income (loss) attributable to AK Steel Holding Corporation	$35.20	($31.70)	($40.40)	($9.90)	($230.40)	($60.90)	($724.20)	($11.80)	($46.80)	($1,027.30)	($155.60)
Less: distributed earnings to common stockholders and holders of certain stock compensation awards	'	'	'	'	'	'	'	'	0	11	22
Undistributed earnings (loss)	'	'	'	'	'	'	'	'	-46.8	-1,038.30	-177.6
Common stockholders earnings - basic [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Distributed earnings to common stockholders	'	'	'	'	'	'	'	'	0	11	22
Undistributed earnings (loss) to common stockholders - basic	'	'	'	'	'	'	'	'	-46.6	-1,034.60	-176.9
Common stockholders earnings (loss) - basic	'	'	'	'	'	'	'	'	-46.6	-1,023.60	-154.9
Common stockholders earnings - diluted [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Distributed earnings to common stockholders	'	'	'	'	'	'	'	'	0	11	22
Undistributed earnings to common stockholders - diluted	'	'	'	'	'	'	'	'	-46.6	-1,034.60	-176.9
Common stockholders earnings - diluted	'	'	'	'	'	'	'	'	($46.60)	($1,023.60)	($154.90)
Common shares outstanding (weighted-average shares in millions) [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Common shares outstanding for basic earnings per share (in shares)	'	'	'	'	'	'	'	'	135.8	113	109.8
Effect of exchangeable debt	'	'	'	'	'	'	'	'	0	0	0
Effect of dilutive stock-based compensation (in shares)	'	'	'	'	'	'	'	'	0	0	0
Common shares outstanding for diluted earnings per share (in shares)	'	'	'	'	'	'	'	'	135.8	113	109.8
Basic earnings per share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Distributed earnings - basic (in dollars per share)	'	'	'	'	'	'	'	'	$0	$0.10	$0.20
Undistributed earnings (loss) - basic (in dollars per share)	'	'	'	'	'	'	'	'	($0.34)	($9.16)	($1.61)
Basic earnings (loss) per share (in dollars per share)	'	'	'	'	'	'	'	'	($0.34)	($9.06)	($1.41)
Diluted earnings per share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Distributed earnings - diluted (in dollars per share)	'	'	'	'	'	'	'	'	$0	$0.10	$0.20
Undistributed earnings (loss) - diluted (in dollars per share)	'	'	'	'	'	'	'	'	($0.34)	($9.16)	($1.61)
Diluted earnings (loss) per share (in dollars per share)	'	'	'	'	'	'	'	'	($0.34)	($9.06)	($1.41)
Potentially issuable common shares excluded from earnings per share calculation due to anti-dilutive effect (in millions of shares)	'	'	'	'	'	'	'	'	2.6	2.4	1.2

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]	'	'	'
Income (loss) before income taxes	$7	($208.60)	($254.10)
SunCoke Middletown [Member] | Variable Interest Entity, Primary Beneficiary [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Expected Production Of Coke, In Tons	550,000	'	'
Expected Production Of Electricity, In Megawatts	45	'	'
Variable interest entity, ownership percentage	0.00%	'	'
Income (loss) before income taxes	$64.30	$46	($7.80)
Vicksmetal Armco Associates [Member] | Variable Interest Entity, Primary Beneficiary [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Variable interest entity, ownership percentage	50.00%	'	'

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

In Millions, unless otherwise specified

Estimate of Fair Value Measurement [Member]

Estimate of Fair Value Measurement [Member]

Estimate of Fair Value Measurement [Member]

Estimate of Fair Value Measurement [Member]

Estimate of Fair Value Measurement [Member]

Estimate of Fair Value Measurement [Member]

Reported Value Measurement [Member]

Reported Value Measurement [Member]

Reported Value Measurement [Member]

Reported Value Measurement [Member]

Reported Value Measurement [Member]

Reported Value Measurement [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Commodity Contract [Member]

Assets [Member]

Liability [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Long-term Debt [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Cash and Cash Equivalents [Member]

Other Noncurrent Assets [Member]

Other Noncurrent Assets [Member]

Other Noncurrent Assets [Member]

Other Noncurrent Assets [Member]

Other Noncurrent Assets [Member]

Other Noncurrent Assets [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Fair Value, Measurements, Recurring [Member]

Maximum [Member]

Maximum [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Other Current Assets [Member]

Other Current Assets [Member]

Other Current Assets [Member]

Other Current Assets [Member]

Other Current Assets [Member]

Other Current Assets [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Accrued Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 1 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Inputs, Level 2 [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Benchmark interest rates for contracts (in hundredths)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.00%

1.00%

Assets measured at fair value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$45.30

$227

$45.30

$227

$0

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commodity hedge contracts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.9

25.5

0

0

4.9

25.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Available for sale investments-cash and cash equivalents

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

18.6

26.3

18.6

26.3

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assets measured at fair value

'

'

'

'

'

'

'

'

'

'

'

'

68.8

278.8

63.9

253.3

4.9

25.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liabilities measured at fair value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign exchange contracts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-0.7

-0.2

0

0

-0.7

-0.2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commodity hedge contracts-current

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-0.4

-1.3

0

0

-0.4

-1.3

'

'

'

'

'

'

'

'

Commodity hedge contracts-noncurrent

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-0.1

0

0

0

-0.1

0

'

'

Liabilities measured at fair value

'

'

'

'

'

'

'

'

'

'

'

'

-1.2

-1.5

0

0

-1.2

-1.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, including current maturities

($1,659.90)

($1,379.30)

$0

$0

($1,659.90)

($1,379.30)

($1,507)

($1,411.90)

$0

$0

($1,507)

($1,411.90)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Disclosures_About_Derivative_I2

Disclosures About Derivative Instruments and Hedging Activities (Details) (EUR €)	Dec. 31, 2013	Dec. 31, 2012
	lb	lb
Commodity Contract [Member] | Nickel [Member]	'	'
Derivative [Line Items]	'	'
Nonmonetary Notional Amount of Derivatives	763,300	420,100
Commodity Contract [Member] | Natural Gas [Member]	'	'
Derivative [Line Items]	'	'
Nonmonetary Notional Amount of Derivatives	3,240,000	9,000,000
Commodity Contract [Member] | Zinc [Member]	'	'
Derivative [Line Items]	'	'
Nonmonetary Notional Amount of Derivatives	12,000,000	0
Commodity Contract [Member] | Iron Ore [Member]	'	'
Derivative [Line Items]	'	'
Nonmonetary Notional Amount of Derivatives	190,735	1,140,000
Commodity Contract [Member] | Hot roll carbon steel coils [Member]	'	'
Derivative [Line Items]	'	'
Nonmonetary Notional Amount of Derivatives	74,147	30,000
Foreign Exchange Contract [Member]	'	'
Derivative [Line Items]	'	'
Derivative, Notional Amount	17,730,000	15,950,000

Disclosures_About_Derivative_I3

Disclosures About Derivative Instruments and Hedging Activities (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, current	$2.60	$25.50
Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] | Commodity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative liabilities, current	0	-1.2
Not Designated as Hedging Instrument [Member] | Other Current Assets [Member] | Commodity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets, current	2.3	0
Not Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] | Foreign Exchange Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative liabilities, current	-0.7	-0.2
Not Designated as Hedging Instrument [Member] | Accrued Liabilities [Member] | Commodity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative liabilities, current	-0.4	-0.1
Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member] | Commodity Contract [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative liabilities, noncurrent	($0.10)	$0

Disclosures_About_Derivative_I4

Disclosures About Derivative Instruments and Hedging Activities (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Natural Gas [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative maturity dates of settlement	'January 2014 to December 2014	'	'
Gains (losses) before tax expected to be reclassified into earnings within the next twelve months	$2.30	'	'
Zinc [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Derivative maturity dates of settlement	'January 2014 to December 2014	'	'
Gains (losses) before tax expected to be reclassified into earnings within the next twelve months	0.5	'	'
Foreign Exchange Contract [Member] | Other Income [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Recognized gains (losses) in consolidated statement of operations	-0.1	-1.2	0.8
Commodity Contract [Member] | Sales [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Recognized gains (losses) in consolidated statement of operations	-3.1	0	0
Commodity Contract [Member] | Cost of Products Sold [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Recognized gains (losses) in consolidated statement of operations	1.7	-0.6	-5.1
Cash Flow Hedging [Member] | Commodity Contract [Member] | Sales [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Reclassification of losses (gains) from accumulated other comprehensive income to net income (loss)	0.4	0	0
Cash Flow Hedging [Member] | Commodity Contract [Member] | Cost of Products Sold [Member]	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Reclassification of losses (gains) from accumulated other comprehensive income to net income (loss)	24.8	-36.3	-4
Recognized in cost of products sold (ineffective portion and amount excluded from effectiveness testing)	$3.30	$0.10	($10.20)

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Supplemental Cash Flow Information [Abstract]	'	'	'	'
Interest, net of capitalized interest	$116.20	$69.50	$44.30	'
Income taxes	1.2	1.3	0.1	'
Supplemental Cash Flow [Line Items]	'	'	'	'
Net cash flows from operating activities	-110.2	-270.8	-180.5	'
Cash and Cash Equivalents, at Carrying Value	45.3	227	42	216.8
Supplemental cash flow, noncash investing and financing activities [Abstract]	'	'	'	'
Issuance of restricted stock and restricted stock units	3	5.4	5.7	'
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]	'	'	'	'
Supplemental cash flow, noncash investing and financing activities [Abstract]	'	'	'	'
Capital investments	10.2	13.9	10.2	'
AK Coal [Member]	'	'	'	'
Supplemental cash flow, noncash investing and financing activities [Abstract]	'	'	'	'
Issuance of note payable for AK Coal purchase (at fair value)	0	0	10.2	'
Variable Interest Entity, Primary Beneficiary [Member] | SunCoke Middletown [Member]	'	'	'	'
Supplemental Cash Flow [Line Items]	'	'	'	'
Net cash flows from operating activities	82.6	55.2	-15.7	'
Cash and Cash Equivalents, at Carrying Value	14.2	0	'	'
Supplemental cash flow, noncash investing and financing activities [Abstract]	'	'	'	'
Capital investments	$0	$0	$16.30	'

Consolidated_Quarterly_Sales_a2

Consolidated Quarterly Sales and Earning (Losses) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net sales	$1,464.80	$1,331.30	$1,404.50	$1,369.80	$1,423.10	$1,463.50	$1,538.40	$1,508.70	$5,570.40	$5,933.70	$6,468
Operating profit (loss)	63	25.9	13.7	33.2	-176.9	-12	56.7	4.1	135.8	-128.1	-201.3
Net income (loss) attributable to AK Holding	35.2	-31.7	-40.4	-9.9	-230.4	-60.9	-724.2	-11.8	-46.8	-1,027.30	-155.6
Basic and diluted earnings (loss) per share (in dollars per share)	$0.26	($0.23)	($0.30)	($0.07)	($1.89)	($0.55)	($6.55)	($0.11)	($0.34)	($9.06)	($1.41)
Pension corridor charges	'	'	'	'	157.3	'	'	'	0	157.3	268.1
Increase in deferred tax asset valuation allowance	'	'	'	'	'	'	$736	'	'	'	'

Supplemental_Guarantor_Informa2

Supplemental Guarantor Information (Details) (USD $)

1 Months Ended

3 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Nov. 30, 2012

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Condensed Statements of Operations [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net sales

'

$1,464.80

$1,331.30

$1,404.50

$1,369.80

$1,423.10

$1,463.50

$1,538.40

$1,508.70

$5,570.40

$5,933.70

$6,468

'

Cost of products sold (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

5,107.80

5,539.10

6,036.80

'

Selling and administrative expenses (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

205.3

208.7

215.4

'

Depreciation

'

'

'

'

'

'

'

'

'

190.1

192

185

'

Pension and OPEB expense (income) (exclusive of corridor charges shown below)

'

'

'

'

'

'

'

'

'

-68.6

-35.3

-36

'

Pension corridor charge

'

'

'

'

'

157.3

'

'

'

0

157.3

268.1

'

Total operating costs

'

'

'

'

'

'

'

'

'

5,434.60

6,061.80

6,669.30

'

Operating profit (loss)

'

63

25.9

13.7

33.2

-176.9

-12

56.7

4.1

135.8

-128.1

-201.3

'

Interest expense

'

'

'

'

'

'

'

'

'

127.4

86.7

47.5

'

Other income (expense)

'

'

'

'

'

'

'

'

'

-1.4

6.2

-5.3

'

Income (loss) before income taxes

'

'

'

'

'

'

'

'

'

7

-208.6

-254.1

'

Income tax expense (benefit)

'

'

'

'

'

'

'

'

'

-10.4

790

-94

'

Equity in net income (loss) of subsidiaries

'

'

'

'

'

'

'

'

'

0

0

0

'

Net income (loss)

'

'

'

'

'

'

'

'

'

17.4

-998.6

-160.1

'

Less: Net income (loss) attributable to noncontrolling interests

'

'

'

'

'

'

'

'

'

64.2

28.7

-4.5

'

Net income (loss) attributable to AK Steel Holding Corporation

'

35.2

-31.7

-40.4

-9.9

-230.4

-60.9

-724.2

-11.8

-46.8

-1,027.30

-155.6

'

Other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

322.3

-1.6

-89.9

'

Comprehensive income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

275.5

-1,028.90

-245.5

'

Current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

45.3

'

'

'

227

'

'

'

45.3

227

42

'

Accounts receivable, net

'

525.2

'

'

'

473.9

'

'

'

525.2

473.9

'

'

Inventory, net

'

586.6

'

'

'

609.2

'

'

'

586.6

609.2

'

'

Deferred tax assets, current

'

69.6

'

'

'

73.2

'

'

'

69.6

73.2

'

'

Other current assets

'

46.5

'

'

'

59.4

'

'

'

46.5

59.4

'

'

Total current assets

'

1,273.20

'

'

'

1,442.70

'

'

'

1,273.20

1,442.70

'

'

Property, plant and equipment

'

5,871.90

'

'

'

5,943.90

'

'

'

5,871.90

5,943.90

'

'

Accumulated depreciation

'

-3,991.80

'

'

'

-3,931.60

'

'

'

-3,991.80

-3,931.60

'

'

Property, plant and equipment, net

'

1,880.10

'

'

'

2,012.30

'

'

'

1,880.10

2,012.30

'

'

Other non-current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Magnetation LLC

'

187.8

'

'

'

150

'

'

'

187.8

150

'

'

Investment in affiliates

'

0

'

'

'

0

'

'

'

0

0

'

'

Inter-company accounts

'

0

'

'

'

0

'

'

'

0

0

'

'

Other non-current assets

'

264.6

'

'

'

298.1

'

'

'

264.6

298.1

'

'

TOTAL ASSETS

'

3,605.70

'

'

'

3,903.10

'

'

'

3,605.70

3,903.10

'

'

Current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable

'

601.8

'

'

'

538.3

'

'

'

601.8

538.3

'

'

Accrued liabilities

'

142.9

'

'

'

164.8

'

'

'

142.9

164.8

'

'

Current portion of long-term debt

'

0.8

'

'

'

0.7

'

'

'

0.8

0.7

'

'

Current portion of pension and other postretirement benefit obligations

'

85.9

'

'

'

108.6

'

'

'

85.9

108.6

'

'

Total current liabilities

'

831.4

'

'

'

812.4

'

'

'

831.4

812.4

'

'

Non-current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

1,506.20

'

'

'

1,411.20

'

'

'

1,506.20

1,411.20

'

'

Pension and other postretirement benefit obligations

'

965.4

'

'

'

1,661.70

'

'

'

965.4

1,661.70

'

'

Other non-current liabilities

'

110

'

'

'

108.8

'

'

'

110

108.8

'

'

TOTAL LIABILITIES

'

3,413

'

'

'

3,994.10

'

'

'

3,413

3,994.10

'

'

Total stockholders' equity (deficit)

'

-221

'

'

'

-505.3

'

'

'

-221

-505.3

'

'

Noncontrolling interests

'

413.7

'

'

'

414.3

'

'

'

413.7

414.3

'

'

TOTAL EQUITY (DEFICIT)

'

192.7

'

'

'

-91

'

'

'

192.7

-91

377.2

641.1

TOTAL LIABILITIES AND EQUITY (DEFICIT)

'

3,605.70

'

'

'

3,903.10

'

'

'

3,605.70

3,903.10

'

'

Condensed Cash Flows [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net cash flows from operating activities

'

'

'

'

'

'

'

'

'

-110.2

-270.8

-180.5

'

Cash flows from investing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital investments

'

'

'

'

'

'

'

'

'

-63.6

-64.1

-296.1

'

Investments in acquired businesses

'

'

'

'

'

'

'

'

'

-50

-60.6

-125.4

'

Other investing items, net

'

'

'

'

'

'

'

'

'

15.1

6.1

1.3

'

Net cash flows from investing activities

'

'

'

'

'

'

'

'

'

-98.5

-118.6

-420.2

'

Cash flows from financing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net borrowings (repayments) under credit facility

'

'

'

'

'

'

'

'

'

90

-250

250

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

31.9

873.3

0

'

Redemption of long-term debt

'

'

'

'

'

'

'

'

'

-27.4

-74

-0.7

'

Proceeds from issuance of common stock

96.4

'

'

'

'

'

'

'

'

0

96.4

0

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

-3.4

-22.3

-10.1

'

Common stock dividends paid

'

'

'

'

'

'

'

'

'

0

-11

-22

'

Inter-company activity

'

'

'

'

'

'

'

'

'

0

0

0

'

SunCoke Middletown advances from (distributions to) noncontrolling interest owners

'

'

'

'

'

'

'

'

'

-64.8

-36.6

210.7

'

Other financing items, net

'

'

'

'

'

'

'

'

'

0.7

-1.4

-2

'

Net cash flows from financing activities

'

'

'

'

'

'

'

'

'

27

574.4

425.9

'

Net increase (decrease) in cash and cash equivalents

'

'

'

'

'

'

'

'

'

-181.7

185

-174.8

'

Cash and cash equivalents, beginning of year

'

'

'

'

227

'

'

'

42

227

42

216.8

'

Cash and cash equivalents, end of year

'

45.3

'

'

'

227

'

'

'

45.3

227

42

'

AK Holding [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Condensed Statements of Operations [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net sales

'

'

'

'

'

'

'

'

'

0

0

0

'

Cost of products sold (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

0

0

0

'

Selling and administrative expenses (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

4.4

4.4

4.4

'

Depreciation

'

'

'

'

'

'

'

'

'

0

0

0

'

Pension and OPEB expense (income) (exclusive of corridor charges shown below)

'

'

'

'

'

'

'

'

'

0

0

0

'

Pension corridor charge

'

'

'

'

'

'

'

'

'

'

0

0

'

Total operating costs

'

'

'

'

'

'

'

'

'

4.4

4.4

4.4

'

Operating profit (loss)

'

'

'

'

'

'

'

'

'

-4.4

-4.4

-4.4

'

Interest expense

'

'

'

'

'

'

'

'

'

0

0

0

'

Other income (expense)

'

'

'

'

'

'

'

'

'

0

0

0

'

Income (loss) before income taxes

'

'

'

'

'

'

'

'

'

-4.4

-4.4

-4.4

'

Income tax expense (benefit)

'

'

'

'

'

'

'

'

'

0

0

-1.8

'

Equity in net income (loss) of subsidiaries

'

'

'

'

'

'

'

'

'

-42.4

-1,022.90

-153

'

Net income (loss)

'

'

'

'

'

'

'

'

'

-46.8

-1,027.30

-155.6

'

Less: Net income (loss) attributable to noncontrolling interests

'

'

'

'

'

'

'

'

'

0

0

0

'

Net income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

-46.8

-1,027.30

-155.6

'

Other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

322.3

-1.6

-89.9

'

Comprehensive income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

275.5

-1,028.90

-245.5

'

Current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

0

'

'

'

0

'

'

'

0

0

0

'

Accounts receivable, net

'

0

'

'

'

0

'

'

'

0

0

'

'

Inventory, net

'

0

'

'

'

0

'

'

'

0

0

'

'

Deferred tax assets, current

'

0

'

'

'

0

'

'

'

0

0

'

'

Other current assets

'

0.3

'

'

'

0.2

'

'

'

0.3

0.2

'

'

Total current assets

'

0.3

'

'

'

0.2

'

'

'

0.3

0.2

'

'

Property, plant and equipment

'

0

'

'

'

0

'

'

'

0

0

'

'

Accumulated depreciation

'

0

'

'

'

0

'

'

'

0

0

'

'

Property, plant and equipment, net

'

0

'

'

'

0

'

'

'

0

0

'

'

Other non-current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Magnetation LLC

'

0

'

'

'

0

'

'

'

0

0

'

'

Investment in affiliates

'

-2,772.40

'

'

'

-2,660.70

'

'

'

-2,772.40

-2,660.70

'

'

Inter-company accounts

'

2,551.10

'

'

'

2,155.20

'

'

'

2,551.10

2,155.20

'

'

Other non-current assets

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL ASSETS

'

-221

'

'

'

-505.3

'

'

'

-221

-505.3

'

'

Current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable

'

0

'

'

'

0

'

'

'

0

0

'

'

Accrued liabilities

'

0

'

'

'

0

'

'

'

0

0

'

'

Current portion of long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Current portion of pension and other postretirement benefit obligations

'

0

'

'

'

0

'

'

'

0

0

'

'

Total current liabilities

'

0

'

'

'

0

'

'

'

0

0

'

'

Non-current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Pension and other postretirement benefit obligations

'

0

'

'

'

0

'

'

'

0

0

'

'

Other non-current liabilities

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL LIABILITIES

'

0

'

'

'

0

'

'

'

0

0

'

'

Total stockholders' equity (deficit)

'

-221

'

'

'

-505.3

'

'

'

-221

-505.3

'

'

Noncontrolling interests

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL EQUITY (DEFICIT)

'

-221

'

'

'

-505.3

'

'

'

-221

-505.3

'

'

TOTAL LIABILITIES AND EQUITY (DEFICIT)

'

-221

'

'

'

-505.3

'

'

'

-221

-505.3

'

'

Condensed Cash Flows [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net cash flows from operating activities

'

'

'

'

'

'

'

'

'

-3.5

-3.5

-1.7

'

Cash flows from investing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital investments

'

'

'

'

'

'

'

'

'

0

0

0

'

Investments in acquired businesses

'

'

'

'

'

'

'

'

'

0

0

0

'

Other investing items, net

'

'

'

'

'

'

'

'

'

0

0

0

'

Net cash flows from investing activities

'

'

'

'

'

'

'

'

'

0

0

0

'

Cash flows from financing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net borrowings (repayments) under credit facility

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

0

0

'

'

Redemption of long-term debt

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of common stock

'

'

'

'

'

'

'

'

'

'

96.4

'

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

0

0

0

'

Common stock dividends paid

'

'

'

'

'

'

'

'

'

'

-11

-22

'

Inter-company activity

'

'

'

'

'

'

'

'

'

4.1

-80.2

25

'

SunCoke Middletown advances from (distributions to) noncontrolling interest owners

'

'

'

'

'

'

'

'

'

0

0

0

'

Other financing items, net

'

'

'

'

'

'

'

'

'

-0.6

-1.7

-1.3

'

Net cash flows from financing activities

'

'

'

'

'

'

'

'

'

3.5

3.5

1.7

'

Net increase (decrease) in cash and cash equivalents

'

'

'

'

'

'

'

'

'

0

0

0

'

Cash and cash equivalents, beginning of year

'

'

'

'

0

'

'

'

0

0

0

0

'

Cash and cash equivalents, end of year

'

0

'

'

'

0

'

'

'

0

0

0

'

AK Steel [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Condensed Statements of Operations [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net sales

'

'

'

'

'

'

'

'

'

5,339.30

5,676.60

6,205.90

'

Cost of products sold (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

5,012.10

5,416.80

5,854.10

'

Selling and administrative expenses (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

205

212.9

222.3

'

Depreciation

'

'

'

'

'

'

'

'

'

169.4

172.8

177.4

'

Pension and OPEB expense (income) (exclusive of corridor charges shown below)

'

'

'

'

'

'

'

'

'

-68.6

-35.3

-36

'

Pension corridor charge

'

'

'

'

'

'

'

'

'

'

157.3

268.1

'

Total operating costs

'

'

'

'

'

'

'

'

'

5,317.90

5,924.50

6,485.90

'

Operating profit (loss)

'

'

'

'

'

'

'

'

'

21.4

-247.9

-280

'

Interest expense

'

'

'

'

'

'

'

'

'

125.9

85.9

47.3

'

Other income (expense)

'

'

'

'

'

'

'

'

'

-5.9

-9.6

-8.4

'

Income (loss) before income taxes

'

'

'

'

'

'

'

'

'

-110.4

-343.4

-335.7

'

Income tax expense (benefit)

'

'

'

'

'

'

'

'

'

-27.8

735.9

-125.6

'

Equity in net income (loss) of subsidiaries

'

'

'

'

'

'

'

'

'

40.2

56.4

57.1

'

Net income (loss)

'

'

'

'

'

'

'

'

'

-42.4

-1,022.90

-153

'

Less: Net income (loss) attributable to noncontrolling interests

'

'

'

'

'

'

'

'

'

0

0

0

'

Net income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

-42.4

-1,022.90

-153

'

Other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

322.3

-1.6

-89.9

'

Comprehensive income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

279.9

-1,024.50

-242.9

'

Current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

16.8

'

'

'

203.6

'

'

'

16.8

203.6

19.9

'

Accounts receivable, net

'

492.4

'

'

'

484.4

'

'

'

492.4

484.4

'

'

Inventory, net

'

520

'

'

'

504.2

'

'

'

520

504.2

'

'

Deferred tax assets, current

'

69.4

'

'

'

73

'

'

'

69.4

73

'

'

Other current assets

'

43.9

'

'

'

57.6

'

'

'

43.9

57.6

'

'

Total current assets

'

1,142.50

'

'

'

1,322.80

'

'

'

1,142.50

1,322.80

'

'

Property, plant and equipment

'

5,258.40

'

'

'

5,355.10

'

'

'

5,258.40

5,355.10

'

'

Accumulated depreciation

'

-3,881.70

'

'

'

-3,841.90

'

'

'

-3,881.70

-3,841.90

'

'

Property, plant and equipment, net

'

1,376.70

'

'

'

1,513.20

'

'

'

1,376.70

1,513.20

'

'

Other non-current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Magnetation LLC

'

0

'

'

'

0

'

'

'

0

0

'

'

Investment in affiliates

'

1,393.80

'

'

'

1,337.40

'

'

'

1,393.80

1,337.40

'

'

Inter-company accounts

'

-3,479.70

'

'

'

-3,066.50

'

'

'

-3,479.70

-3,066.50

'

'

Other non-current assets

'

141

'

'

'

167.7

'

'

'

141

167.7

'

'

TOTAL ASSETS

'

574.3

'

'

'

1,274.60

'

'

'

574.3

1,274.60

'

'

Current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable

'

550.5

'

'

'

494.8

'

'

'

550.5

494.8

'

'

Accrued liabilities

'

133.6

'

'

'

155

'

'

'

133.6

155

'

'

Current portion of long-term debt

'

0.8

'

'

'

0.7

'

'

'

0.8

0.7

'

'

Current portion of pension and other postretirement benefit obligations

'

85.4

'

'

'

108.1

'

'

'

85.4

108.1

'

'

Total current liabilities

'

770.3

'

'

'

758.6

'

'

'

770.3

758.6

'

'

Non-current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

1,506.20

'

'

'

1,411.20

'

'

'

1,506.20

1,411.20

'

'

Pension and other postretirement benefit obligations

'

960.6

'

'

'

1,657.20

'

'

'

960.6

1,657.20

'

'

Other non-current liabilities

'

109.6

'

'

'

108.3

'

'

'

109.6

108.3

'

'

TOTAL LIABILITIES

'

3,346.70

'

'

'

3,935.30

'

'

'

3,346.70

3,935.30

'

'

Total stockholders' equity (deficit)

'

-2,772.40

'

'

'

-2,660.70

'

'

'

-2,772.40

-2,660.70

'

'

Noncontrolling interests

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL EQUITY (DEFICIT)

'

-2,772.40

'

'

'

-2,660.70

'

'

'

-2,772.40

-2,660.70

'

'

TOTAL LIABILITIES AND EQUITY (DEFICIT)

'

574.3

'

'

'

1,274.60

'

'

'

574.3

1,274.60

'

'

Condensed Cash Flows [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net cash flows from operating activities

'

'

'

'

'

'

'

'

'

-251.1

-360

-216.9

'

Cash flows from investing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital investments

'

'

'

'

'

'

'

'

'

-39.2

-38.3

-98.9

'

Investments in acquired businesses

'

'

'

'

'

'

'

'

'

0

0

0

'

Other investing items, net

'

'

'

'

'

'

'

'

'

8.5

6.7

1.4

'

Net cash flows from investing activities

'

'

'

'

'

'

'

'

'

-30.7

-31.6

-97.5

'

Cash flows from financing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net borrowings (repayments) under credit facility

'

'

'

'

'

'

'

'

'

90

-250

250

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

31.9

873.3

'

'

Redemption of long-term debt

'

'

'

'

'

'

'

'

'

-27.4

-74

-0.7

'

Proceeds from issuance of common stock

'

'

'

'

'

'

'

'

'

'

0

'

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

-3.4

-22.3

-10.1

'

Common stock dividends paid

'

'

'

'

'

'

'

'

'

'

0

0

'

Inter-company activity

'

'

'

'

'

'

'

'

'

3.9

48.8

-106.4

'

SunCoke Middletown advances from (distributions to) noncontrolling interest owners

'

'

'

'

'

'

'

'

'

0

0

0

'

Other financing items, net

'

'

'

'

'

'

'

'

'

0

-0.5

0.1

'

Net cash flows from financing activities

'

'

'

'

'

'

'

'

'

95

575.3

132.9

'

Net increase (decrease) in cash and cash equivalents

'

'

'

'

'

'

'

'

'

-186.8

183.7

-181.5

'

Cash and cash equivalents, beginning of year

'

'

'

'

203.6

'

'

'

19.9

203.6

19.9

201.4

'

Cash and cash equivalents, end of year

'

16.8

'

'

'

203.6

'

'

'

16.8

203.6

19.9

'

Other Non-Guarantor Subsidiaries [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Condensed Statements of Operations [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net sales

'

'

'

'

'

'

'

'

'

830.3

906.3

756.7

'

Cost of products sold (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

652.3

738

635.1

'

Selling and administrative expenses (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

36.7

35.3

36.4

'

Depreciation

'

'

'

'

'

'

'

'

'

20.7

19.2

7.6

'

Pension and OPEB expense (income) (exclusive of corridor charges shown below)

'

'

'

'

'

'

'

'

'

0

0

0

'

Pension corridor charge

'

'

'

'

'

'

'

'

'

'

0

0

'

Total operating costs

'

'

'

'

'

'

'

'

'

709.7

792.5

679.1

'

Operating profit (loss)

'

'

'

'

'

'

'

'

'

120.6

113.8

77.6

'

Interest expense

'

'

'

'

'

'

'

'

'

1.5

0.8

0.2

'

Other income (expense)

'

'

'

'

'

'

'

'

'

4.5

15.8

3.1

'

Income (loss) before income taxes

'

'

'

'

'

'

'

'

'

123.6

128.8

80.5

'

Income tax expense (benefit)

'

'

'

'

'

'

'

'

'

18.1

49.9

31.2

'

Equity in net income (loss) of subsidiaries

'

'

'

'

'

'

'

'

'

0

0

0

'

Net income (loss)

'

'

'

'

'

'

'

'

'

105.5

78.9

49.3

'

Less: Net income (loss) attributable to noncontrolling interests

'

'

'

'

'

'

'

'

'

64.2

28.7

-4.5

'

Net income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

41.3

50.2

53.8

'

Other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

1.2

0.7

-0.7

'

Comprehensive income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

42.5

50.9

53.1

'

Current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

28.5

'

'

'

23.4

'

'

'

28.5

23.4

22.1

'

Accounts receivable, net

'

61.1

'

'

'

54.3

'

'

'

61.1

54.3

'

'

Inventory, net

'

77.7

'

'

'

114.4

'

'

'

77.7

114.4

'

'

Deferred tax assets, current

'

0.2

'

'

'

0.2

'

'

'

0.2

0.2

'

'

Other current assets

'

2.3

'

'

'

1.6

'

'

'

2.3

1.6

'

'

Total current assets

'

169.8

'

'

'

193.9

'

'

'

169.8

193.9

'

'

Property, plant and equipment

'

613.5

'

'

'

588.8

'

'

'

613.5

588.8

'

'

Accumulated depreciation

'

-110.1

'

'

'

-89.7

'

'

'

-110.1

-89.7

'

'

Property, plant and equipment, net

'

503.4

'

'

'

499.1

'

'

'

503.4

499.1

'

'

Other non-current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Magnetation LLC

'

187.8

'

'

'

150

'

'

'

187.8

150

'

'

Investment in affiliates

'

0

'

'

'

0

'

'

'

0

0

'

'

Inter-company accounts

'

896.7

'

'

'

843.8

'

'

'

896.7

843.8

'

'

Other non-current assets

'

123.6

'

'

'

130.4

'

'

'

123.6

130.4

'

'

TOTAL ASSETS

'

1,881.30

'

'

'

1,817.20

'

'

'

1,881.30

1,817.20

'

'

Current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable

'

51.9

'

'

'

44.4

'

'

'

51.9

44.4

'

'

Accrued liabilities

'

9.3

'

'

'

9.8

'

'

'

9.3

9.8

'

'

Current portion of long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Current portion of pension and other postretirement benefit obligations

'

0.5

'

'

'

0.5

'

'

'

0.5

0.5

'

'

Total current liabilities

'

61.7

'

'

'

54.7

'

'

'

61.7

54.7

'

'

Non-current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Pension and other postretirement benefit obligations

'

4.8

'

'

'

4.5

'

'

'

4.8

4.5

'

'

Other non-current liabilities

'

0.4

'

'

'

0.5

'

'

'

0.4

0.5

'

'

TOTAL LIABILITIES

'

66.9

'

'

'

59.7

'

'

'

66.9

59.7

'

'

Total stockholders' equity (deficit)

'

1,400.70

'

'

'

1,343.20

'

'

'

1,400.70

1,343.20

'

'

Noncontrolling interests

'

413.7

'

'

'

414.3

'

'

'

413.7

414.3

'

'

TOTAL EQUITY (DEFICIT)

'

1,814.40

'

'

'

1,757.50

'

'

'

1,814.40

1,757.50

'

'

TOTAL LIABILITIES AND EQUITY (DEFICIT)

'

1,881.30

'

'

'

1,817.20

'

'

'

1,881.30

1,817.20

'

'

Condensed Cash Flows [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net cash flows from operating activities

'

'

'

'

'

'

'

'

'

180

113.1

39.7

'

Cash flows from investing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital investments

'

'

'

'

'

'

'

'

'

-24.4

-25.8

-197.2

'

Investments in acquired businesses

'

'

'

'

'

'

'

'

'

-50

-60.6

-125.4

'

Other investing items, net

'

'

'

'

'

'

'

'

'

6.6

-0.6

-0.1

'

Net cash flows from investing activities

'

'

'

'

'

'

'

'

'

-67.8

-87

-322.7

'

Cash flows from financing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net borrowings (repayments) under credit facility

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

0

0

'

'

Redemption of long-term debt

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of common stock

'

'

'

'

'

'

'

'

'

'

0

'

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

0

0

0

'

Common stock dividends paid

'

'

'

'

'

'

'

'

'

'

0

0

'

Inter-company activity

'

'

'

'

'

'

'

'

'

-43.6

11

79.8

'

SunCoke Middletown advances from (distributions to) noncontrolling interest owners

'

'

'

'

'

'

'

'

'

-64.8

-36.6

210.7

'

Other financing items, net

'

'

'

'

'

'

'

'

'

1.3

0.8

-0.8

'

Net cash flows from financing activities

'

'

'

'

'

'

'

'

'

-107.1

-24.8

289.7

'

Net increase (decrease) in cash and cash equivalents

'

'

'

'

'

'

'

'

'

5.1

1.3

6.7

'

Cash and cash equivalents, beginning of year

'

'

'

'

23.4

'

'

'

22.1

23.4

22.1

15.4

'

Cash and cash equivalents, end of year

'

28.5

'

'

'

23.4

'

'

'

28.5

23.4

22.1

'

Eliminations [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Condensed Statements of Operations [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net sales

'

'

'

'

'

'

'

'

'

-599.2

-649.2

-494.6

'

Cost of products sold (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

-556.6

-615.7

-452.4

'

Selling and administrative expenses (exclusive of items shown separately below)

'

'

'

'

'

'

'

'

'

-40.8

-43.9

-47.7

'

Depreciation

'

'

'

'

'

'

'

'

'

0

0

0

'

Pension and OPEB expense (income) (exclusive of corridor charges shown below)

'

'

'

'

'

'

'

'

'

0

0

0

'

Pension corridor charge

'

'

'

'

'

'

'

'

'

'

0

0

'

Total operating costs

'

'

'

'

'

'

'

'

'

-597.4

-659.6

-500.1

'

Operating profit (loss)

'

'

'

'

'

'

'

'

'

-1.8

10.4

5.5

'

Interest expense

'

'

'

'

'

'

'

'

'

0

0

0

'

Other income (expense)

'

'

'

'

'

'

'

'

'

0

0

0

'

Income (loss) before income taxes

'

'

'

'

'

'

'

'

'

-1.8

10.4

5.5

'

Income tax expense (benefit)

'

'

'

'

'

'

'

'

'

-0.7

4.2

2.2

'

Equity in net income (loss) of subsidiaries

'

'

'

'

'

'

'

'

'

2.2

966.5

95.9

'

Net income (loss)

'

'

'

'

'

'

'

'

'

1.1

972.7

99.2

'

Less: Net income (loss) attributable to noncontrolling interests

'

'

'

'

'

'

'

'

'

0

0

0

'

Net income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

1.1

972.7

99.2

'

Other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

-323.5

0.9

90.6

'

Comprehensive income (loss) attributable to AK Steel Holding Corporation

'

'

'

'

'

'

'

'

'

-322.4

973.6

189.8

'

Current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash and cash equivalents

'

0

'

'

'

0

'

'

'

0

0

0

'

Accounts receivable, net

'

-28.3

'

'

'

-64.8

'

'

'

-28.3

-64.8

'

'

Inventory, net

'

-11.1

'

'

'

-9.4

'

'

'

-11.1

-9.4

'

'

Deferred tax assets, current

'

0

'

'

'

0

'

'

'

0

0

'

'

Other current assets

'

0

'

'

'

0

'

'

'

0

0

'

'

Total current assets

'

-39.4

'

'

'

-74.2

'

'

'

-39.4

-74.2

'

'

Property, plant and equipment

'

0

'

'

'

0

'

'

'

0

0

'

'

Accumulated depreciation

'

0

'

'

'

0

'

'

'

0

0

'

'

Property, plant and equipment, net

'

0

'

'

'

0

'

'

'

0

0

'

'

Other non-current assets:

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment in Magnetation LLC

'

0

'

'

'

0

'

'

'

0

0

'

'

Investment in affiliates

'

1,378.60

'

'

'

1,323.30

'

'

'

1,378.60

1,323.30

'

'

Inter-company accounts

'

31.9

'

'

'

67.5

'

'

'

31.9

67.5

'

'

Other non-current assets

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL ASSETS

'

1,371.10

'

'

'

1,316.60

'

'

'

1,371.10

1,316.60

'

'

Current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Accounts payable

'

-0.6

'

'

'

-0.9

'

'

'

-0.6

-0.9

'

'

Accrued liabilities

'

0

'

'

'

0

'

'

'

0

0

'

'

Current portion of long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Current portion of pension and other postretirement benefit obligations

'

0

'

'

'

0

'

'

'

0

0

'

'

Total current liabilities

'

-0.6

'

'

'

-0.9

'

'

'

-0.6

-0.9

'

'

Non-current liabilities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

'

0

'

'

'

0

'

'

'

0

0

'

'

Pension and other postretirement benefit obligations

'

0

'

'

'

0

'

'

'

0

0

'

'

Other non-current liabilities

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL LIABILITIES

'

-0.6

'

'

'

-0.9

'

'

'

-0.6

-0.9

'

'

Total stockholders' equity (deficit)

'

1,371.70

'

'

'

1,317.50

'

'

'

1,371.70

1,317.50

'

'

Noncontrolling interests

'

0

'

'

'

0

'

'

'

0

0

'

'

TOTAL EQUITY (DEFICIT)

'

1,371.70

'

'

'

1,317.50

'

'

'

1,371.70

1,317.50

'

'

TOTAL LIABILITIES AND EQUITY (DEFICIT)

'

1,371.10

'

'

'

1,316.60

'

'

'

1,371.10

1,316.60

'

'

Condensed Cash Flows [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

Net cash flows from operating activities

'

'

'

'

'

'

'

'

'

-35.6

-20.4

-1.6

'

Cash flows from investing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital investments

'

'

'

'

'

'

'

'

'

0

0

0

'

Investments in acquired businesses

'

'

'

'

'

'

'

'

'

0

0

0

'

Other investing items, net

'

'

'

'

'

'

'

'

'

0

0

0

'

Net cash flows from investing activities

'

'

'

'

'

'

'

'

'

0

0

0

'

Cash flows from financing activities:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net borrowings (repayments) under credit facility

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of long-term debt

'

'

'

'

'

'

'

'

'

0

0

'

'

Redemption of long-term debt

'

'

'

'

'

'

'

'

'

0

0

0

'

Proceeds from issuance of common stock

'

'

'

'

'

'

'

'

'

'

0

'

'

Debt issuance costs

'

'

'

'

'

'

'

'

'

0

0

0

'

Common stock dividends paid

'

'

'

'

'

'

'

'

'

'

0

0

'

Inter-company activity

'

'

'

'

'

'

'

'

'

35.6

20.4

1.6

'

SunCoke Middletown advances from (distributions to) noncontrolling interest owners

'

'

'

'

'

'

'

'

'

0

0

0

'

Other financing items, net

'

'

'

'

'

'

'

'

'

0

0

0

'

Net cash flows from financing activities

'

'

'

'

'

'

'

'

'

35.6

20.4

1.6

'

Net increase (decrease) in cash and cash equivalents

'

'

'

'

'

'

'

'

'

0

0

0

'

Cash and cash equivalents, beginning of year

'

'

'

'

0

'

'

'

0

0

0

0

'

Cash and cash equivalents, end of year

'

$0

'

'

'

$0

'

'

'

$0

$0

$0

'