Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

Description of the credit facility's borrowing capacity including discussion of how the borrowing capacity is determined (for example, borrowing capacity based on the amount of current assets).

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- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

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- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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Long-Term Debt New Senior Secured Credit Facilities (Details) - USD ($) $ in Millions		12 Months Ended
	Apr. 06, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt		$ 2,862.7	$ 30.3	$ 16.8
Payments of Debt Issuance Costs		$ 91.0	0.0	$ 0.0
Line of Credit Facility, Interest Rate Description		The Term Loan A Facility and the Revolving Credit Facility will mature on April 6, 2022, and the Term Loan B Facility will mature on April 6, 2024. Borrowings under the New Senior Secured Credit Facilities bear interest at rates based on the applicable Eurodollar rate or alternate base rate, as AAM may elect, in each case plus an applicable margin determined based on AAM’s total net leverage ratio. The alternate base rate is the greatest of (a) the prime rate of a major United States financial institution, (b) the Federal Reserve Bank of New York rate plus 0.50% and (c) the adjusted Eurodollar rate plus 1.00%. The applicable margin for Eurodollar-based loans under the New Senior Secured Credit Facilities will be between 1.25% and 2.25% with respect to any loan under the Term Loan A Facility, 2.25% with respect to any loan under the Term Loan B Facility, and between 2.00% and 3.00% with respect to any loan under the Revolving Credit Facility. The applicable margin for loans subject to alternate base rate will be between 0.25% and 1.25% with respect to any loan under the Term Loan A Facility, 1.25% with respect to any loan under the Term Loan B Facility, and between 1.00% and 2.00% with respect to any loan under the Revolving Credit Facility.
Line of Credit Facility, Borrowing Capacity, Description		The Credit Agreement permits AAM, Inc. to incur incremental term loan borrowings and/or increase commitments under the Revolving Credit Facility, subject to certain limitations and the satisfaction of certain conditions, in an aggregate amount not to exceed (i) $600 million, plus (ii) certain voluntary prepayments, plus (iii) additional amounts subject to pro forma compliance with a first lien net leverage ratio for Holdings and its restricted subsidiaries.
Term Loan A [Member]
Debt Instrument [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost		$ 5.0
Term Loan B [Member]
Debt Instrument [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost		15.5
New Senior Secured Credit Facilities [Member]
Debt Instrument [Line Items]
Payments of Debt Issuance Costs		54.0
New Multi-Currency Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity		866.2
Letters of Credit Outstanding, Amount		33.8
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding		$ 0.0	$ 0.0
Metaldyne Performance Group, Inc. [Member] \| New Multi-Currency Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	$ 900.0
Metaldyne Performance Group, Inc. [Member] \| Term Loan A [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	100.0
Metaldyne Performance Group, Inc. [Member] \| Term Loan B [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	$ 1,550.0
Metaldyne Performance Group, Inc. [Member] \| 7.375% Notes - MPG [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.375%