Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Net pre-tax income (loss) tax benefit not recorded	$ 3	$ 19	$ 47

Net pre-tax income (loss) for which a tax benefit is not recorded.

No definition available.

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