Represents the minimum age criteria for plan eligibility under base contribution plan.

No definition available.

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Namespace Prefix:	mga_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum service period for plan eligibility under base contribution plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer base contribution for each eligible participant determined by multiplying with their applicable regular earnings.

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanEmployerBaseContributionParticipantRegularEarningsPercent
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the enrollment opt out period under (employee benefit plan (EBP)).

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanEnrollmentOptOutPeriod
Namespace Prefix:	mga_
Data Type:	xbrli:durationItemType
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Period Type:	duration

- Definition

Percentage of contribution after increase in pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), contributes to total pretax annual compensation.

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanMaximumContributionAfterAutomaticIncreasePercent
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Threshold percent of contribution for increase in pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), contributes to total pretax annual compensation.

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum age criteria for plan eligibility under (employee benefit plan (EBP)).

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the minimum service period for plan eligibility under (employee benefit plan (EBP)).

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of automatic increase per year in pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), contributes to total pretax annual compensation.

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanParticipantContributionAutomaticIncreasePerYearPercent
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of pretax annual compensation that new hires are automatically enrolled to contribute to total pretax annual compensation in employee stock purchase, saving, or similar plan (employee benefit plan (EBP).

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanParticipantContributionNewHiresAutomaticEnrollmentAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of pretax annual compensation that new hires, who are covered by certain collective bargaining agreements, are automatically enrolled to contribute to total pretax annual compensation in employee stock purchase, saving, or similar plan (employee benefit plan (EBP).

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanParticipantContributionNewHiresCoveredByCollectiveBargainingAgreementsAutomaticEnrollmentAnnualCompensationToTotalCompensationPercentage
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of pretax annual bonus that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

No definition available.

+ Details

Name:	mga_EmployeeBenefitPlanParticipantContributionPretaxAnnualBonusToTotalCompensationPercentage
Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of minimum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the service period expressed in hours, for profit sharing eligibility under (employee benefit plan (EBP)).

+ References

No definition available.

+ Details

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Namespace Prefix:	mga_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates (true false) whether description of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) is published and made available.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanDescriptionOfPlanLineItems
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

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Namespace Prefix:
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- Details

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Description of the Plan (Details) - The Magna Group of Companies Retirement Savings Plans		12 Months Ended
	Jan. 01, 2022 age	Dec. 31, 2025 item age	Dec. 31, 2024
Description of the Plan
Description of plan available		true
Minimum service period for Plan eligibility		6 months
Minimum age for Plan eligibility		18
Service period for profit sharing eligibility (in hours) \| item		1,000
Minimum amount of compensation eligible for participant contribution (as a percent)		1.00%
Percentage of automatic enrollment for newly hires		6.00%
Percentage of automatic enrollment for newly hires covered under certain bargaining agreements		3.00%
Maximum amount of compensation eligible for participant contribution (as a percent)		50.00%
Employer matching contribution (as a percent)		50.00%	50.00%
Participant compensation matched (as a percent)		6.00%	6.00%
Opt out period		30 days
Employee contribution automatic increase per year (as a percent)		1.00%
Employee contribution after automatic increase (as a percent)		6.00%
Employee contribution automatic increase, threshold (as a percent)		6.00%
Magna Base Contribution (as a percent)	3.00%
Magna Base Contribution, service period	6 months
Magna Base Contribution, minimum age for eligibility	18
Minimum
Description of the Plan
Participant's annual bonus deferral rate (as a percent)		1.00%
Maximum
Description of the Plan
Participant's annual bonus deferral rate (as a percent)		100.00%