Organization and Basis of Presentation (Policies)	3 Months Ended
Organization and Basis of Presentation (Policies)	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation We have prepared the accompanying interim condensed consolidated financial statements in accordance with the instructions to Form 10-Q under the Securities Exchange Act of 1934. These condensed consolidated financial statements are unaudited but include all normal recurring adjustments, which we consider necessary for a fair presentation of the information set forth herein. Results of operations for the periods presented are not necessarily indicative of the results for the full fiscal year. The balance sheet at December 31, 2017 presented herein has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America (GAAP) for complete consolidated financial statements. In order to prepare the accompanying interim condensed consolidated financial statements, we are required to make estimates and assumptions that affect the reported amounts and disclosures in our interim condensed consolidated financial statements. Actual results could differ from those estimates. For further information, refer to the audited consolidated financial statements and notes included in our Annual Report on Form 10-K for the year ended December 31, 2017.
New Accounting Pronouncements, Policy [Policy Text Block]	Effect of New Accounting Standards Accounting Standards Update 2018-02 On February 14, 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2018-02 - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220). ASU 2018-02 allows companies the option to reclassify disproportionate tax effects in accumulated other comprehensive income (AOCI) caused by the 2017 Tax Cuts and Jobs Act, also known as stranded tax effects, to retained earnings. ASU 2018-02 also requires expanded disclosures related to disproportionate income tax effects from AOCI, some of which are applicable to all companies regardless of whether the option to reclassify the stranded tax effects is exercised. This guidance becomes effective at the beginning of our 2019 fiscal year, however early adoption is permitted for financial statements which have not yet been issued. We are currently assessing the impact that this standard will have on our consolidated financial statements. Accounting Standards Update 2017-04 On January 26, 2017, the FASB issued ASU 2017-04 - Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The amendments in this update modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. An entity no longer will determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination, or what is referred to under existing guidance as "Step 2." Instead, under the amendments in this update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. This guidance becomes effective at the beginning of our 2020 fiscal year and early adoption is permitted. The guidance requires a prospective transition method. We do not expect the adoption of this guidance to have a material effect on our consolidated financial statements, however, goodwill could be more susceptible to impairment in periods subsequent to adoption. Accounting Standards Update 2016-02 On February 25, 2016, the FASB issued ASU 2016-02 - Leases (Topic 842), which supersedes the existing lease accounting guidance and establishes new criteria for recognizing lease assets and liabilities. The most significant impact of the update, to AAM, is that a lessee will be required to recognize a "right-of-use" asset and lease liability for operating lease agreements that were not previously included on the balance sheet under the existing lease guidance. A lessee will be permitted to make a policy election, excluding recognition of the right-of-use asset and associated liability for lease terms of 12 months or less. Expense recognition in the statement of income along with cash flow statement classification for both financing (capital) and operating leases under the new standard will not be significantly changed from existing lease guidance. This guidance becomes effective for AAM at the beginning of our 2019 fiscal year and requires transition under a modified retrospective method. We are currently assessing the impact that this standard will have on our consolidated financial statements.