CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income (loss)	$ (8.2)	$ 22.6	$ 46.8	$ 107.1
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Defined benefit plans	(102.7)	0.4	(117.2)	3.9
Foreign currency translation adjustments	4.9	(30.2)	(7.1)	(16.7)
Change in derivatives	2.2	(9.0)	7.6	(7.9)
Other comprehensive loss	(95.6)	(38.8)	(116.7)	(20.7)
Comprehensive income (loss)	(103.8)	(16.2)	(69.9)	86.4
Net loss attributable to the noncontrolling interests	0.1	2.2	1.0	4.6
Foreign currency translation adjustments attributable to noncontrolling interests	0	0.5	(0.2)	(0.3)
Comprehensive income (loss) attributable to AAM	$ (103.7)	$ (13.5)	$ (69.1)	$ 90.7

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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Amount of Net Income (Loss) attributable to noncontrolling interest.

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Net of tax and reclassification adjustments amount of the change in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Also includes an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Net of tax and reclassifications amount of pension and other postretirement benefit plans (gain) loss included in accumulated other comprehensive income (loss).

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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