Income Taxes (Notes)	9 Months Ended
Income Taxes (Notes)	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Our effective tax rate was 18.9% and 18.4% for the three and nine months ended September 30, 2012, respectively, and (1.1)% and 6.3% for the three and nine months ended September 30, 2011, respectively. The effective tax rate for the three and nine months ended September 30, 2012 and 2011 differed from the federal statutory rate applied to income and losses before income taxes primarily as a result of the mix of income, losses and tax rates between tax jurisdictions and valuation allowances. We have valuation allowances recorded to reduce certain deferred tax assets to amounts that are more likely than not to be realized. The valuation allowances relate to the potential inability to realize our deferred tax assets associated with amortization, pension and postretirement liabilities in the U.S. and depreciation and net operating loss carryforwards in non-U.S. jurisdictions. We intend to maintain our valuation allowances until sufficient positive evidence exists (such as cumulative positive earnings and estimated future taxable income) to support their reversal. As of September 30, 2012, we have $16.6 of unrecognized tax benefits. We recognize interest and penalties related to uncertain tax positions within the “Provision for (benefit from) income taxes” in the Consolidated Statements of Comprehensive Income. As of September 30, 2012, we had approximately $2.3 of accrued interest related to uncertain tax positions. The 2005 through 2011 tax years remain open to examination. A non-U.S. jurisdiction commenced an examination in the fourth quarter of 2009 that is anticipated to be completed within six months of September 30, 2012.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 136, 172

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 43, 44, 45, 46, 47, 48, 49

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

Aleris International, Inc. 10-Q