Environmental and Legal Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Environmental-related capital investments	$ 7.2	$ 1.6	$ 1.0
Environmental compliance costs	$ 112.4aks_EnvironmentalComplianceCosts	$ 101.1aks_EnvironmentalComplianceCosts	$ 101.6aks_EnvironmentalComplianceCosts

Amount of environmental remediation costs capitalized. These expenditures may relate to long-lived improvements in operating facilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 25

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=39739230&loc=d3e11660-110855

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration