XML 142 R105.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Stock-Based Compensation - Summary of Stock-Based Compensation Expense Recorded in Selling, General and Administrative Expenses (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Incentive Stock Option Plan [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | $ 40 | $ 42 | $ 31
Selling, general and administrative expenses [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | 35 | 38 | 34
Selling, general and administrative expenses [Member] | Incentive Stock Option Plan [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | 15 | 19 | 21
Selling, general and administrative expenses [Member] | Long-term retention [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | 4 | 5 | 7
Selling, general and administrative expenses [Member] | Restricted stock unit [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | 16 | 14 | 6
Selling, general and administrative expenses [Member] | Fair value adjustment for liability classified DSUs [Member] |  |  |
Stock Based Compensation [Line Items] |  |  |
Incentive Stock Option Plan | $ 5 | $ 4 | $ (3)

X
- Details
Name: | mga_StockBasedCompensationLineItems
Namespace Prefix: | mga_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
Name: | us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration