Number of traunches of warrants issued.

No definition available.

Name:	gm_NumberOfTraunchesOfWarrantsIssued
Namespace Prefix:	gm_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Expiration date of warrants held.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column A

+ Details

Name:	invest_InvestmentWarrantsExpirationDate
Namespace Prefix:	invest_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- 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

No definition available.

+ Details

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

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_ClassOfWarrantOrRightOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=gm_MlcWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=gm_FirstTrauncheofMLCWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=gm_SecondTrauncheofMLCWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stockholders' Equity Warrants (Details) shares in Millions	6 Months Ended	9 Months Ended
Stockholders' Equity Warrants (Details) shares in Millions	Jul. 10, 2016 $ / shares	Sep. 30, 2016 $ / shares shares	Sep. 30, 2015 shares	Dec. 31, 2009 shares
Class of Warrant or Right [Line Items]
Outstanding Warrants \| shares		45	121
MLC Warrants [Member]
Class of Warrant or Right [Line Items]
Number Of Tranches of Warrants Issued				2
Number of Securities Called by Warrants \| shares				136
First Traunche of MLC Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise Price of Warrants \| $ / shares	$ 10.00
Warrants Expiration Date	Jul. 10, 2016
Second Traunche of MLC Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise Price of Warrants \| $ / shares		$ 18.33
Warrants Expiration Date		Jul. 10, 2019