Post Retirement Benefits (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Postretirement benefits:
Defined Benefit Plan, Changes in Benefit Obligation and Plan Assets, Description		In August 2010, as part of a new collective-bargaining agreement, the post retirement health and life insurance benefits for all current and future represented employees who were not retired were eliminated in exchange for a one-time cash payment. Individuals who retired prior to August 2010 remain eligible for post retirement health and life insurance benefits.
Defined Benefit Plan, Plan Name [Extensible Enumeration]		cmt:NavistarsPostRetirementHealthAndLifeInsuranceBenefitPlanMember
Defined Benefit Plan, Type [Extensible Enumeration]		Post retirement health and life insurance benefit plan
Defined Benefit Plan, Sponsor Location [Extensible Enumeration]			us-gaap:DomesticPlanMember
Defined Benefit Plan, Accumulated Benefit Obligation, Increase (Decrease) for Plan Amendment		$ (10,282,000)
Amortization of prior service costs		496,000	$ 496,000	$ 496,000
Actuarial gain (loss)		945,000	1,956,000
Amounts that will be amortized from accumulated other comprehensive income in next fiscal year:
Interest cost		235,000	285,000	$ 277,000
Post retirement health and life insurance benefit plan
Postretirement benefits:
Unrecognized loss (gain)		(102,000)	1,099,000
Actuarial gain (loss)		$ (1,047,000)	(857,000)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Immediate Recognition of Actuarial Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Accumulated Other Comprehensive Income (Loss), Net of Tax
Amounts that will be amortized from accumulated other comprehensive income in next fiscal year:
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year		$ (1,763,000)	(1,976,000)
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year		496,000	173,000
Interest cost		237,000	285,000
Defined Benefit Plan, Expected Amortization, Next Fiscal Year		$ 161,000	$ 162,000
Assumed health care cost trend rates:
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		5.10%	6.00%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate			5.00%
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate		2027
Post retirement health and life insurance benefit plan | Medical pre age 65
Assumed health care cost trend rates:
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Post retirement health and life insurance benefit plan | Medical post age 65
Assumed health care cost trend rates:
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		4.25%
Post retirement health and life insurance benefit plan | Drugs - all ages
Assumed health care cost trend rates:
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%
Scenario plan
Postretirement benefits:
Amortization of prior service costs	$ 496,000