Document and Entity Information Document - shares	6 Months Ended
	Jun. 30, 2019	Jul. 25, 2019
Document Information [Line Items]
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Document Quarterly Report	true
Document Transition Report	false
Current Fiscal Year End Date	--12-31
Entity File Number	1-13696
Entity Registrant Name	AK STEEL HOLDING CORPORATION
Entity Central Index Key	0000918160
Entity Incorporation, State or Country Code	DE
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
Title of 12(b) Security	Common Stock $0.01 Par Value
Trading Symbol	AKS
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		316,384,868