v3.19.3.a.u2

Document and Entity Information Document	Feb. 20, 2020
Document Information [Line Items]
Document Type	8-K
Document Period End Date	Feb. 20, 2020
Amendment Flag	false
Entity Registrant Name	AK STEEL HOLDING CORPORATION
Entity Central Index Key	0000918160
Entity Incorporation, State or Country Code	DE
Entity File Number	1-13696
Entity Tax Identification Number	31-1401455
Entity Address, Address Line One	9227 Centre Pointe Drive
Entity Address, City or Town	West Chester
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45069
City Area Code	(513)
Local Phone Number	425-5000
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock $0.01 Par Value
Trading Symbol	AKS
Security Exchange Name	NYSE

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

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No definition available.

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Data Type:	xbrli:booleanItemType
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- Definition

Area code of city

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No definition available.

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Data Type:	xbrli:normalizedStringItemType
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD.

+ References

No definition available.

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Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:	dei_DocumentType
Namespace Prefix:	dei_
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Balance Type:	na
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- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

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Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
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- Definition

Name of the City or Town

+ References

No definition available.

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Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Code for the postal or zip code

+ References

No definition available.

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Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
Period Type:	duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

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Namespace Prefix:	dei_
Data Type:	dei:stateOrProvinceItemType
Balance Type:	na
Period Type:	duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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Namespace Prefix:	dei_
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Period Type:	duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

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Namespace Prefix:	dei_
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- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

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Data Type:	dei:edgarStateCountryItemType
Balance Type:	na
Period Type:	duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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Balance Type:	na
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- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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Data Type:	dei:employerIdItemType
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- Definition

Local phone number for entity.

+ References

No definition available.

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Namespace Prefix:	dei_
Data Type:	xbrli:normalizedStringItemType
Balance Type:	na
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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 13e
-Subsection 4c

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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 14d
-Subsection 2b

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- Definition

Title of a 12(b) registered security.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
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-Section 12
-Subsection b

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- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Number 240
-Section 12
-Subsection d1-1

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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Exchange Act
-Section 14a
-Number 240
-Subsection 12

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Balance Type:	na
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- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

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Namespace Prefix:	dei_
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Balance Type:	na
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- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Securities Act
-Number 230
-Section 425

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AK STEEL HOLDING CORP 8-K