Segment and Geographic Information (Tables)

12 Months Ended

Dec. 31, 2023

Segments, Geographical Areas [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	Year Ended December 31, 2023
	Driveline		Metal Forming		Corporate and Eliminations		Total
	(in millions)
Sales	$	4,176.7	$	2,454.3	$	—	$	6,631.0
Less: Intersegment sales	0.2		551.3		—		551.5
Net external sales	$	4,176.5	$	1,903.0	$	—	$	6,079.5
Segment adjusted EBITDA	$	543.6	$	149.7	$	—	$	693.3
Depreciation and amortization	$	260.3	$	226.9	$	—	$	487.2
Capital expenditures	$	105.9	$	80.1	$	8.6	$	194.6
Total assets	$	2,554.3	$	1,788.7	$	1,013.3	$	5,356.3

	Year Ended December 31, 2022
	Driveline		Metal Forming		Corporate and Eliminations		Total
Sales	$	4,063.5	$	2,280.7	$	—	$	6,344.2
Less: Intersegment sales	—		541.8		—		541.8
Net external sales	$	4,063.5	$	1,738.9	$	—	$	5,802.4
Segment adjusted EBITDA	$	510.9	$	236.4	$	—	$	747.3
Depreciation and amortization	$	272.7	$	219.4	$	—	$	492.1
Capital expenditures	$	103.3	$	62.9	$	5.2	$	171.4
Total assets	$	2,542.0	$	1,900.3	$	1,027.1	$	5,469.4

	Year Ended December 31, 2021
	Driveline		Metal Forming		Corporate and Eliminations		Total
Sales	$	3,695.3	$	1,912.8	$	—	$	5,608.1
Less: Intersegment sales	0.2		451.3		—		451.5
Net external sales	$	3,695.1	$	1,461.5	$	—	$	5,156.6
Segment adjusted EBITDA	$	541.8	$	291.5	$	—	$	833.3
Depreciation and amortization	$	293.8	$	250.5	$	—	$	544.3
Capital expenditures	$	123.4	$	53.9	$	3.9	$	181.2
Total assets	$	2,852.0	$	1,650.5	$	1,133.2	$	5,635.7

Assets included in the Corporate and Eliminations column of the tables above represent AAM corporate assets, as well as eliminations of intercompany assets.

Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]

The following table represents a reconciliation of Segment Adjusted EBITDA to consolidated income (loss) before income taxes for the years ended December 31, 2023, 2022 and 2021:

	Year Ended December 31,
	2023		2022		2021
	(in millions)
Segment adjusted EBITDA	$	693.3	$	747.3	$	833.3
Interest expense	(201.7)		(174.5)		(195.2)
Depreciation and amortization	(487.2)		(492.1)		(544.3)
Restructuring and acquisition-related costs	(25.2)		(30.2)		(49.4)
Pension curtailment and settlement charges	(1.3)		—		(42.3)
Loss on sale of business	—		—		(2.7)
Unrealized gain (loss) on equity securities	(1.1)		(25.5)		24.4
Debt refinancing and redemption costs	(1.3)		(6.4)		(34.0)
Malvern Fire insurance recoveries, net of charges	—		39.1		11.4
Acquisition-related fair value inventory adjustment	—		(5.0)		—
Gain on bargain purchase of business	—		13.6		—
Income (loss) before income taxes	$	(24.5)	$	66.3	$	1.2

Schedule of Disclosure on Geographic Areas, Revenue and Long-Lived Assets by Country [Table Text Block]

Financial information relating to our operations by geographic area is presented in the following table. Net sales are attributed to countries based upon location of production. Long-lived assets exclude deferred income taxes.

	December 31,
	2023		2022		2021
	(in millions)
Net sales
United States	$	2,163.5	$	2,148.0	$	1,923.5
Mexico	2,273.5		2,293.2		2,058.9
South America	184.4		137.4		94.3
China	271.6		280.0		299.6
All other Asia	273.1		213.3		189.4
Europe	913.4		730.5		590.9
Total net sales	$	6,079.5	$	5,802.4	$	5,156.6
Long-lived assets
United States	$	1,694.3	$	1,778.9	$	1,976.5
Mexico	778.4		821.3		888.1
South America	75.8		71.2		40.9
China	110.9		130.1		164.8
All other Asia	79.2		80.5		87.1
Europe	441.7		475.0		501.2
Total long-lived assets	$	3,180.3	$	3,357.0	$	3,658.6