Supplemental Guarantor Condensed Consolidating Statements of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Ownership in subsidiary, percentage	100.00%		100.00%
Net sales
External	$ 820.8	$ 702.9	$ 2,376.0	$ 2,194.2
Intercompany	0	0	0	0
Total net sales	820.8	702.9	2,376.0	2,194.2
Cost of goods sold	695.5	612.2	2,024.2	1,878.5
Gross profit	125.3	90.7	351.8	315.7
Selling, general and administrative expenses	57.8	60.6	177.9	177.9
Operating income	67.5	30.1	173.9	137.8
Non-operating income (expense), net	(29.8)	(37.4)	(100.1)	(86.2)
Income (loss) before income taxes	37.7	(7.3)	73.8	51.6
Income tax expense (benefit)	6.1	0.9	9.1	4.8
Earnings (loss) from equity in subsidiaries	0	0	0	0
Net income (loss) before royalties and dividends	31.6	(8.2)	64.7	46.8
Royalties and dividends	0	0	0	0
Net income (loss) after royalties and dividends	31.6	(8.2)	64.7	46.8
Net loss attributable to noncontrolling interests	0	0.1	0	1.0
Net income (loss) attributable to AAM	31.6	(8.1)	64.7	47.8
Other comprehensive (income) loss, net of tax	17.0	(95.6)	(0.8)	(116.7)
Foreign currency translation adjustments attributable to noncontrolling interests	0	0	0	0.2
Comprehensive income (loss) attributable to AAM	48.6	(103.7)	63.9	(69.1)
Holdings [Member]
Net sales
External	0	0	0	0
Intercompany	0	0	0	0
Total net sales	0	0	0	0
Cost of goods sold	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expenses	0	0	0	0
Operating income	0	0	0	0
Non-operating income (expense), net	0	0	0	0
Income (loss) before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Earnings (loss) from equity in subsidiaries	31.6	(8.1)	64.7	47.8
Net income (loss) before royalties and dividends	31.6	(8.1)	64.7	47.8
Royalties and dividends	0	0	0	0
Net income (loss) after royalties and dividends	31.6	(8.1)	64.7	47.8
Net loss attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to AAM	31.6	(8.1)	64.7	47.8
Other comprehensive (income) loss, net of tax	17.0	(95.6)	(0.8)	(116.7)
Foreign currency translation adjustments attributable to noncontrolling interests				0.2
Comprehensive income (loss) attributable to AAM	48.6	(103.7)	63.9	(69.1)
AAM Inc. [Member]
Net sales
External	162.6	162.2	574.2	542.6
Intercompany	5.0	3.5	13.0	14.9
Total net sales	167.6	165.7	587.2	557.5
Cost of goods sold	170.1	164.3	566.3	544.7
Gross profit	(2.5)	1.4	20.9	12.8
Selling, general and administrative expenses	48.1	50.0	149.3	148.2
Operating income	(50.6)	(48.6)	(128.4)	(135.4)
Non-operating income (expense), net	(30.6)	(35.7)	(101.4)	(84.5)
Income (loss) before income taxes	(81.2)	(84.3)	(229.8)	(219.9)
Income tax expense (benefit)	0.9	0.1	(13.0)	0.4
Earnings (loss) from equity in subsidiaries	50.7	34.5	115.6	133.8
Net income (loss) before royalties and dividends	(31.4)	(49.9)	(101.2)	(86.5)
Royalties and dividends	63.0	41.8	165.9	134.3
Net income (loss) after royalties and dividends	31.6	(8.1)	64.7	47.8
Net loss attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to AAM	31.6	(8.1)	64.7	47.8
Other comprehensive (income) loss, net of tax	17.0	(95.6)	(0.8)	(116.7)
Foreign currency translation adjustments attributable to noncontrolling interests				0.2
Comprehensive income (loss) attributable to AAM	48.6	(103.7)	63.9	(69.1)
Guarantor Subsidiaries [Member]
Net sales
External	57.8	55.4	170.5	164.7
Intercompany	55.2	54.4	169.1	174.5
Total net sales	113.0	109.8	339.6	339.2
Cost of goods sold	97.2	97.7	293.3	298.3
Gross profit	15.8	12.1	46.3	40.9
Selling, general and administrative expenses	0	0	0	0
Operating income	15.8	12.1	46.3	40.9
Non-operating income (expense), net	2.5	0.1	7.9	1.3
Income (loss) before income taxes	18.3	12.2	54.2	42.2
Income tax expense (benefit)	0	0	0	0
Earnings (loss) from equity in subsidiaries	(1.5)	(14.7)	(14.4)	(40.9)
Net income (loss) before royalties and dividends	16.8	(2.5)	39.8	1.3
Royalties and dividends	0	0	0	0
Net income (loss) after royalties and dividends	16.8	(2.5)	39.8	1.3
Net loss attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to AAM	16.8	(2.5)	39.8	1.3
Other comprehensive (income) loss, net of tax	(0.8)	4.1	(14.4)	(7.3)
Foreign currency translation adjustments attributable to noncontrolling interests				0
Comprehensive income (loss) attributable to AAM	16.0	1.6	25.4	(6.0)
Non-Guarantor Subsidiaries [Member]
Net sales
External	600.4	485.3	1,631.3	1,486.9
Intercompany	1.7	10.1	9.0	22.3
Total net sales	602.1	495.4	1,640.3	1,509.2
Cost of goods sold	490.1	418.2	1,355.7	1,247.2
Gross profit	112.0	77.2	284.6	262.0
Selling, general and administrative expenses	9.7	10.6	28.6	29.7
Operating income	102.3	66.6	256.0	232.3
Non-operating income (expense), net	(1.7)	(1.8)	(6.6)	(3.0)
Income (loss) before income taxes	100.6	64.8	249.4	229.3
Income tax expense (benefit)	5.2	0.8	22.1	4.4
Earnings (loss) from equity in subsidiaries	0	0	0	0
Net income (loss) before royalties and dividends	95.4	64.0	227.3	224.9
Royalties and dividends	(63.0)	(41.8)	(165.9)	(134.3)
Net income (loss) after royalties and dividends	32.4	22.2	61.4	90.6
Net loss attributable to noncontrolling interests	0	0.1	0	1.0
Net income (loss) attributable to AAM	32.4	22.3	61.4	91.6
Other comprehensive (income) loss, net of tax	(1.7)	5.8	(17.8)	(1.0)
Foreign currency translation adjustments attributable to noncontrolling interests				0.2
Comprehensive income (loss) attributable to AAM	30.7	28.1	43.6	90.4
Elims [Member]
Net sales
External	0	0	0	0
Intercompany	(61.9)	(68.0)	(191.1)	(211.7)
Total net sales	(61.9)	(68.0)	(191.1)	(211.7)
Cost of goods sold	(61.9)	(68.0)	(191.1)	(211.7)
Gross profit	0	0	0	0
Selling, general and administrative expenses	0	0	0	0
Operating income	0	0	0	0
Non-operating income (expense), net	0	0	0	0
Income (loss) before income taxes	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Earnings (loss) from equity in subsidiaries	(80.8)	(11.7)	(165.9)	(140.7)
Net income (loss) before royalties and dividends	(80.8)	(11.7)	(165.9)	(140.7)
Royalties and dividends	0	0	0	0
Net income (loss) after royalties and dividends	(80.8)	(11.7)	(165.9)	(140.7)
Net loss attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to AAM	(80.8)	(11.7)	(165.9)	(140.7)
Other comprehensive (income) loss, net of tax	(14.5)	85.7	33.0	125.0
Foreign currency translation adjustments attributable to noncontrolling interests				(0.4)
Comprehensive income (loss) attributable to AAM	$ (95.3)	$ 74.0	$ (132.9)	$ (15.3)
Secured Debt [Member] \| 9.25% Notes [Member]
Debt instrument, interest rate, stated percentage	9.25%		9.25%
Unsecured Debt [Member] \| 7.75% Notes [Member]
Debt instrument, interest rate, stated percentage	7.75%		7.75%
Unsecured Debt [Member] \| 6.625% Notes [Member]
Debt instrument, interest rate, stated percentage	6.625%		6.625%
Unsecured Debt [Member] \| 6.25% Notes [Member]
Debt instrument, interest rate, stated percentage	6.25%		6.25%

This element represents the income or loss from continuing operations attributable to the economic entity after income or loss from equity method investments, income taxes and royalties and dividends, but before extraordinary items and noncontrolling interest.

No definition available.