Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, at Carrying Value	$ 220.8	$ 257.3
Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member] \| Prepaid expenses and other [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Asset, Carrying and Fair Value Disclosure	7.4	1.2
Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member] \| Other Noncurrent Assets [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Asset, Carrying and Fair Value Disclosure	4.3	0.0
Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member] \| Accrued expenses and other [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Liability, Carrying and Fair Value Disclosure	0.2	14.9
Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member] \| Postretirement benefits and other long-term liabilities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Liability, Carrying and Fair Value Disclosure	0.2	7.3
Foreign Exchange Forward [Member] \| Not Designated as Hedging Instrument [Member] \| Prepaid expenses and other [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Asset, Carrying and Fair Value Disclosure	53.8	0.0
Foreign Exchange Forward [Member] \| Not Designated as Hedging Instrument [Member] \| Accrued expenses and other [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign Currency Contracts, Liability, Carrying and Fair Value Disclosure	0.0	1.6
Fair Value Swap \| Designated as Hedging Instrument [Member] \| Other Noncurrent Assets [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Contracts, Asset, Carrying and Fair Value Disclosure	0.0	0.9
Fair Value Swap \| Designated as Hedging Instrument [Member] \| Postretirement benefits and other long-term liabilities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Contracts, Liability, Carrying and Fair Value Disclosure	22.2	0.0
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Accrued expenses and other [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Liabilities, at Carrying and Fair Value	6.6	2.2
Interest Rate Swap [Member] \| Designated as Hedging Instrument [Member] \| Postretirement benefits and other long-term liabilities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Derivative Liabilities, at Carrying and Fair Value	$ 10.1	$ 5.0

AMERICAN AXLE & MANUFACTURING HOLDINGS INC 10-Q