Allocation of unamortized debt issuance costs to equity component as a reduction of paid-in capital.

No definition available.

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

- Definition

Convertible debt repurchase price including accrued interest

+ References

No definition available.

+ Details

Name:	mtor_ConvertibleNoteRepurchasePrice
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The redemption price at which the company may redeem the convertible notes. The redemption price is equal to 100 percent of the accreted principal amount plus any accrued and upaid interest.

+ References

No definition available.

+ Details

Name:	mtor_ConvertibleNotesRedemptionOptionPrice
Namespace Prefix:	mtor_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The redemption price at which the debtholders may require the company to repurchase all or a portion of their convertible notes. The repurchase price is equal to 100 percent of the accreted principal amount plus any accrued and upaid interest.

+ References

No definition available.

+ Details

Name:	mtor_ConvertibleNotesRepurchaseOptionPrice
Namespace Prefix:	mtor_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The fair value amount of the debt component of convertible debt

+ References

No definition available.

+ Details

Name:	mtor_DebtInstrumentConvertibleFairValueOfDebtComponent
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of the equity component of convertible debt.

+ References

No definition available.

+ Details

Name:	mtor_DebtInstrumentConvertibleFairValueOfEquityComponent
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Deferred tax liability recognized for equity component of convertible notes.

+ References

No definition available.

+ Details

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

- Definition

The equivalent number of shares of common stock per $1,000 of principal amount of convertible notes.

+ References

No definition available.

+ Details

Name:	mtor_EquivalentSharesOfCommonStockPer1000PrincipalAmountOfConvertibleNotes
Namespace Prefix:	mtor_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Face principal amount per note

+ References

No definition available.

+ Details

Name:	mtor_FacePrincipalAmountPerNote
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Initial principal amount per note

+ References

No definition available.

+ Details

Name:	mtor_InitialPrincipalAmountPerNote
Namespace Prefix:	mtor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The maximum number of shares of common stock the convertible notes are convertible into.

+ References

No definition available.

+ Details

Name:	mtor_MaximumNumberOfSharesOfCommonStockConvertibleNotesAreConvertibleInto
Namespace Prefix:	mtor_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Recognition of discount on convertible notes.

+ References

No definition available.

+ Details

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

- Definition

Recognition of estimated equity component of convertible notes, before tax.

+ References

No definition available.

+ Details

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

- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031897-161870

+ Details

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

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instruments must exceed threshold percentage for a specified number of trading days to trigger conversion feature, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

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

- Definition

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentConvertibleThresholdTradingDays
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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

- Definition

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

+ References

+ 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

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 50

-Section 40

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 50

-Section 40

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

+ Details

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

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20, 22

-Article 5

+ Details

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

- Definition

The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromConvertibleDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_SevenAndSevenEighthsPercentConvertibleNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_FourAndFiveEighthPercentConvertibleNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_FourPercentConvertibleNotesDue2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleNotesPayableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_AdoptionOfGuidanceForDebtWithConversionAndOtherOptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_ZeroPointSixTwoFivePercentConvertibleNotesDue2026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_ConvertibleNotes2006Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_ConvertibleNotes2007Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=mtor_ConvertibleNotes2013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mtor_TriggeringEventAxis=mtor_TriggeringEventOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mtor_TriggeringEventAxis=mtor_TriggeringEventTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LONG-TERM DEBT (Convertible Notes) (Details)	1 Months Ended	12 Months Ended
LONG-TERM DEBT (Convertible Notes) (Details)	Dec. 31, 2012 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) d $ / shares shares	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Jun. 11, 2015 USD ($)	Feb. 27, 2007 USD ($)	Mar. 31, 2006 USD ($)
Debt Instrument [Line Items]
Gain (loss) on repayment of debt		$ (25,000,000)	$ (31,000,000)	$ (24,000,000)
7.875 percent convertible notes due 2026
Debt Instrument [Line Items]
Stated interest rate		7.875%	7.875%
4.625 percent convertible notes due 2026
Debt Instrument [Line Items]
Stated interest rate		4.625%	4.625%
4.0 percent convertible notes due 2027
Debt Instrument [Line Items]
Stated interest rate		4.00%	4.00%
Convertible Notes
Debt Instrument [Line Items]
Threshold trading days \| d		20
Threshold consecutive trading days		30 days
Threshold percentage of stock price trigger		120.00%
Gain (loss) on repayment of debt		$ (24,000,000)	$ (5,000,000)	$ (5,000,000)
Carrying amount of equity component		58,000,000	70,000,000
Convertible Notes \| 7.875 percent convertible notes due 2026
Debt Instrument [Line Items]
Debt instrument, face amount	$ 250,000,000
Initial principal amount per note	900
Face principal amount per note	$ 1,000
Effective interest rates on convertible notes:	10.90%
Proceeds from convertible debt	$ 220,000,000
Equivalent shares of common stock per 1000 principal amount of convertible notes \| shares	83.3333
Conversion price \| $ / shares	$ 12.00
Repurchased amount of debt		110,000,000			$ 110,000,000
Long-term debt		$ 127,000,000	224,000,000
Fair value of debt component	$ 216,000,000
Fair value of equity component	9,000,000
Stated interest rate		7.875%
Carrying amount of equity component		$ 58,000,000
Convertible Notes \| Adoption Of Guidance For Debt With Conversion and Other Options
Debt Instrument [Line Items]
Recognition of estimated equity component of convertible notes, before tax		108,000,000
Allocation of unamortized debt issuance costs to equity component reduction of paid in capital		4,000,000
Recognition of discount on convertible notes		108,000,000
Conversion of equity component of convertible notes		39,000,000
Convertible Notes \| 4.625 percent convertible notes due 2026
Debt Instrument [Line Items]
Debt instrument, face amount							$ 300,000,000
Repurchased amount of debt	245,000,000
Long-term debt	300,000,000	$ 55,000,000	55,000,000
Convertible note repurchase price	236,000,000
Gain (loss) on repayment of debt	$ (5,000,000)
Stated interest rate		4.625%
Redemption option price		100.00%
Convertible Notes \| 4.0 percent convertible notes due 2027
Debt Instrument [Line Items]
Debt instrument, face amount						$ 200,000,000
Long-term debt		$ 142,000,000	$ 160,000,000
Stated interest rate		4.00%	4.00%
Redemption option price		100.00%
Repurchase option price		100.00%
Convertible Notes \| 0.625 Percent Convertible Notes Due 2026
Debt Instrument [Line Items]
Repurchase option price		100.00%
Convertible Notes \| Convertible Notes 2006
Debt Instrument [Line Items]
Equivalent shares of common stock per 1000 principal amount of convertible notes \| shares		47.6667
Conversion price \| $ / shares		$ 20.98
Maximum number of shares of common stock convertible notes are convertible into \| shares		3,000,000
Convertible Notes \| Convertible Notes 2007
Debt Instrument [Line Items]
Equivalent shares of common stock per 1000 principal amount of convertible notes \| shares		37.4111
Conversion price \| $ / shares		$ 26.73
Maximum number of shares of common stock convertible notes are convertible into \| shares		6,000,000
Convertible Notes \| 2013
Debt Instrument [Line Items]
Effective interest rates on convertible notes:		10.90%
Maximum number of shares of common stock convertible notes are convertible into \| shares		19,000,000
Triggering Event One \| Convertible Notes
Debt Instrument [Line Items]
Threshold trading days \| d		5
Threshold consecutive trading days		5 days
Threshold percentage of stock price trigger		97.00%
Triggering Event One \| Convertible Notes \| 2013
Debt Instrument [Line Items]
Threshold trading days \| d		20
Threshold consecutive trading days		30 days
Threshold percentage of stock price trigger		120.00%
Triggering Event Two \| Convertible Notes \| 2013
Debt Instrument [Line Items]
Threshold trading days \| d		5
Threshold consecutive trading days		5 days
Threshold percentage of stock price trigger		97.00%