Debt Instrument, Accrued Interest, Repurchase Amount

No definition available.

Name:	mtor_DebtInstrumentAccruedInterestRepurchaseAmount
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRepurchaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow for the extinguishment of long-term borrowing, with the highest claim on the assets of the entity in case of bankruptcy or liquidation, before its maturity.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Name:	us-gaap_EarlyRepaymentOfSeniorDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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-Publisher FASB
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Long-Term Debt - 6.25 Percent Notes (Details) - USD ($)				6 Months Ended
Long-Term Debt - 6.25 Percent Notes (Details) - USD ($)	May 04, 2021	Dec. 16, 2020	Dec. 01, 2020	Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Early repayment of senior debt				$ 281,000,000	$ 0
Loss on debt extinguishment				$ 8,000,000	$ 0
Senior Notes \| 6.25 percent notes due 2024
Debt Instrument [Line Items]
Interest rate (percent)		6.25%		6.25%
Early repayment of senior debt		$ 275,000,000	$ 275,000,000
Debt		450,000,000	$ 450,000,000	$ 175,000,000
Debt instrument aggregate purchase price		287,000,000
Debt instrument, accrued interest repurchase amount		$ 6,000,000
Debt instrument, redemption price		102.083%
Loss on debt extinguishment		$ 8,000,000
Senior Notes \| 6.25 percent notes due 2024 \| Subsequent Event
Debt Instrument [Line Items]
Debt	$ 175,000,000
Debt instrument aggregate purchase price	180,000,000
Debt instrument, accrued interest repurchase amount	$ 3,000,000
Debt instrument, redemption price	101.042%