Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Automotive [Member] \| Not Designated as Hedges [Member]
Derivative [Line Items]
Derivative notional amount	$ 3,413	$ 4,676
Automotive [Member] \| Not Designated as Hedges [Member] \| Foreign Currency [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	2,710	4,022
Automotive [Member] \| Not Designated as Hedges [Member] \| Commodity [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	658	606
Automotive [Member] \| Not Designated as Hedges [Member] \| PSA Warrants [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	45	48
Automotive [Member] \| Not Designated as Hedges [Member] \| Fair Value Hedges [Member] \| PSA Warrants [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative asset	827	764
GM Financial [Member]
Derivative [Line Items]
Derivative notional amount	113,871	98,000
Collateral available for netting	451	299
GM Financial [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Interest Rate Swap [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	768	2,177
GM Financial [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Foreign Currency Swaps [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	2,075	1,574
GM Financial [Member] \| Designated as Hedges [Member] \| Fair Value Hedges [Member] \| Interest Rate Swap [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	9,533	11,110
GM Financial [Member] \| Designated as Hedges [Member] \| Fair Value Hedges [Member] \| Foreign Currency Swaps [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	1,829	0
GM Financial [Member] \| Not Designated as Hedges [Member] \| Foreign Currency Swaps [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	0	1,201
GM Financial [Member] \| Not Designated as Hedges [Member] \| Interest Rate Contract [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative notional amount	99,666	81,938
Other assets [Member] \| GM Financial [Member] \| Not Designated as Hedges [Member] \| Interest Rate Contract [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Fair value of derivative instruments	372	329
Other liabilities [Member] \| GM Financial [Member] \| Designated as Hedges [Member] \| Fair Value Hedges [Member] \| Interest Rate Swap [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Fair value of derivative instruments	291	290
Other liabilities [Member] \| GM Financial [Member] \| Not Designated as Hedges [Member] \| Interest Rate Contract [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Fair value of derivative instruments	$ 520	$ 207

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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- Definition

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41678-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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- 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.

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