XML 99 R123.htm IDEA: XBRL DOCUMENT v2.4.0.8

Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
	Feb. 28, 2014
Subsequent Event [Line Items]
Income tax payable period	3 years
Minimum [Member]
Subsequent Event [Line Items]
Tax expense	$ 25
Maximum [Member]
Subsequent Event [Line Items]
Tax expense	$ 30

X

- Definition

Subsequent Event Income Tax Payable Period

+ References

No definition available.

+ Details

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

X

- Definition

Monetary effect of a change in the tax status effective after year-end but before the financial statements for the reporting period are issued or available to be issue by the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32590-109319

+ Details

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

X

- Details

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