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

No definition available.

Supplemental Guarantor Condensed Consolidating Financial Statements Condensed Consolidating Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ownership in Subsidiary, Percentage	100.00%													100.00%
Net sales
External														$ 6,266.0	$ 3,948.0	$ 3,903.1
Intercompany														0.0	0.0	0.0
Total net sales	$ 1,733.9	$ 1,724.4	$ 1,757.8	$ 1,049.9	$ 946.5	$ 1,006.9	$ 1,025.4	$ 969.2						6,266.0	3,948.0	3,903.1
Cost of goods sold														5,146.9	3,221.9	3,267.7
Gross profit	294.3	297.7	316.4	210.7	179.5	181.2	191.4	174.0						1,119.1	726.1	635.4
Selling, general and administrative expenses														390.1	314.2	274.1
Amortization of intangible assets									$ 100.0	$ 100.0	$ 100.0	$ 100.0	$ 100.0	75.3	5.0	3.2
Restructuring and acquisition-related costs														110.7	26.2	0.0
Operating income (loss)														543.0	380.7	358.1
Non-operating income (expense), net														(203.0)	(81.7)	(85.4)
Income (loss) before income taxes														340.0	299.0	272.7
Income tax expense														2.5	58.3	37.1
Earnings (loss) from equity in subsidiaries														0.0	0.0	0.0
Net income (loss) before royalties														337.5	240.7	235.6
Royalties														0.0	0.0	0.0
Net income after royalties														337.5	240.7	235.6
Net income attributable to noncontrolling interests														(0.4)	0.0	0.0
Net income (loss) attributable to AAM	$ 106.3	$ 86.2	$ 66.2	$ 78.4	$ 46.9	$ 61.7	$ 71.0	$ 61.1						337.1	240.7	235.6
Other comprehensive income, net of tax														96.9	(33.1)	(59.6)
Comprehensive income (loss)														434.0	207.6	176.0
Guarantor Subsidiaries [Member]
Net sales
External														1,668.2	212.2	210.3
Intercompany														285.2	241.6	258.3
Total net sales														1,953.4	453.8	468.6
Cost of goods sold														1,730.9	375.4	385.2
Gross profit														222.5	78.4	83.4
Selling, general and administrative expenses														63.9	0.0	0.1
Amortization of intangible assets														67.5	0.0	0.0
Restructuring and acquisition-related costs														1.9	0.0
Operating income (loss)														89.2	78.4	83.3
Non-operating income (expense), net														18.6	10.9	10.1
Income (loss) before income taxes														107.8	89.3	93.4
Income tax expense														(247.0)	4.2	5.5
Earnings (loss) from equity in subsidiaries														76.1	(16.7)	(20.8)
Net income (loss) before royalties														430.9	68.4	67.1
Royalties														3.6	0.0	0.0
Net income after royalties														434.5	68.4	67.1
Net income attributable to noncontrolling interests														0.0	0.0	0.0
Net income (loss) attributable to AAM														434.5	68.4	67.1
Other comprehensive income, net of tax														87.3	(1.2)	(63.6)
Comprehensive income (loss)														521.8	67.2	3.5
Non-Guarantor Subsidiaries [Member]
Net sales
External														3,523.2	2,626.2	2,543.8
Intercompany														27.5	16.1	19.0
Total net sales														3,550.7	2,642.3	2,562.8
Cost of goods sold														2,734.5	2,048.7	2,054.7
Gross profit														816.2	593.6	508.1
Selling, general and administrative expenses														103.0	70.6	66.6
Amortization of intangible assets														2.2	0.0	0.0
Restructuring and acquisition-related costs														3.6	5.1
Operating income (loss)														707.4	517.9	441.5
Non-operating income (expense), net														(11.6)	4.0	3.8
Income (loss) before income taxes														695.8	521.9	445.3
Income tax expense														55.4	26.7	10.0
Earnings (loss) from equity in subsidiaries														0.0	0.0	0.0
Net income (loss) before royalties														640.4	495.2	435.3
Royalties														(320.9)	(312.9)	(260.9)
Net income after royalties														319.5	182.3	174.4
Net income attributable to noncontrolling interests														(0.4)	0.0	0.0
Net income (loss) attributable to AAM														319.1	182.3	174.4
Other comprehensive income, net of tax														102.6	(12.1)	(68.4)
Comprehensive income (loss)														421.7	170.2	106.0
Holdings [Member]
Net sales
External														0.0	0.0	0.0
Intercompany														0.0	0.0	0.0
Total net sales														0.0	0.0	0.0
Cost of goods sold														0.0	0.0	0.0
Gross profit														0.0	0.0	0.0
Selling, general and administrative expenses														0.0	0.0	0.0
Amortization of intangible assets														0.0	0.0	0.0
Restructuring and acquisition-related costs														0.0	0.0
Operating income (loss)														0.0	0.0	0.0
Non-operating income (expense), net														0.0	0.0	0.0
Income (loss) before income taxes														0.0	0.0	0.0
Income tax expense														0.0	0.0	0.0
Earnings (loss) from equity in subsidiaries														337.1	240.7	235.6
Net income (loss) before royalties														337.1	240.7	235.6
Royalties														0.0	0.0	0.0
Net income after royalties														337.1	240.7	235.6
Net income attributable to noncontrolling interests														0.0	0.0	0.0
Net income (loss) attributable to AAM														337.1	240.7	235.6
Other comprehensive income, net of tax														96.9	(33.1)	(59.6)
Comprehensive income (loss)														434.0	207.6	176.0
AAM Inc. [Member]
Net sales
External														1,074.6	1,109.6	1,149.0
Intercompany														2.4	8.3	9.4
Total net sales														1,077.0	1,117.9	1,158.4
Cost of goods sold														996.6	1,063.8	1,114.5
Gross profit														80.4	54.1	43.9
Selling, general and administrative expenses														223.2	243.6	207.4
Amortization of intangible assets														5.6	5.0	3.2
Restructuring and acquisition-related costs														105.2	21.1
Operating income (loss)														(253.6)	(215.6)	(166.7)
Non-operating income (expense), net														(210.0)	(96.6)	(99.3)
Income (loss) before income taxes														(463.6)	(312.2)	(266.0)
Income tax expense														194.1	27.4	21.6
Earnings (loss) from equity in subsidiaries														289.5	267.4	262.3
Net income (loss) before royalties														(368.2)	(72.2)	(25.3)
Royalties														317.3	312.9	260.9
Net income after royalties														(50.9)	240.7	235.6
Net income attributable to noncontrolling interests														0.0	0.0	0.0
Net income (loss) attributable to AAM														(50.9)	240.7	235.6
Other comprehensive income, net of tax														40.1	(33.1)	(59.6)
Comprehensive income (loss)														(10.8)	207.6	176.0
Consolidation, Eliminations [Member]
Net sales
External														0.0	0.0	0.0
Intercompany														(315.1)	(266.0)	(286.7)
Total net sales														(315.1)	(266.0)	(286.7)
Cost of goods sold														(315.1)	(266.0)	(286.7)
Gross profit														0.0	0.0	0.0
Selling, general and administrative expenses														0.0	0.0	0.0
Amortization of intangible assets														0.0	0.0	0.0
Restructuring and acquisition-related costs														0.0	0.0
Operating income (loss)														0.0	0.0	0.0
Non-operating income (expense), net														0.0	0.0	0.0
Income (loss) before income taxes														0.0	0.0	0.0
Income tax expense														0.0	0.0	0.0
Earnings (loss) from equity in subsidiaries														(702.7)	(491.4)	(477.1)
Net income (loss) before royalties														(702.7)	(491.4)	(477.1)
Royalties														0.0	0.0	0.0
Net income after royalties														(702.7)	(491.4)	(477.1)
Net income attributable to noncontrolling interests														0.0	0.0	0.0
Net income (loss) attributable to AAM														(702.7)	(491.4)	(477.1)
Other comprehensive income, net of tax														(230.0)	46.4	191.6
Comprehensive income (loss)														$ (932.7)	$ (445.0)	$ (285.5)