Debt - Interest Expense and LT Debt Maturities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Apr. 30, 2020
Debt Instrument [Line Items]
2020 (April 1, 2020 to December 31, 2020)	$ 37,673
2021	24,656
2022(b)	17,968
2023	19,403
2024	5,928
2025	5,535
Thereafter	15,411
Total	$ 126,574
Line of Credit [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt term	3 years
Aggregate borrowing capacity	$ 3,000
Line of Credit [Member] \| Three Year Revolving Credit Facility April 2021 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt term	3 years
Aggregate borrowing capacity	$ 4,000
Line of Credit [Member] \| Three Year Revolving Credit Facility April 2022 [Member] \| Unsecured Debt [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Aggregate borrowing capacity		$ 3,600
Automotive [Member]
Debt Instrument [Line Items]
2020 (April 1, 2020 to December 31, 2020)	1,551
2021	1,273
2022(b)	5,129
2023	12,007
2024	62
2025	532
Thereafter	10,240
Total	30,794
Automotive [Member] \| Line of Credit [Member] \| Three Year Revolving Credit Facility April 2021 [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt outstanding	$ 3,000
Debt term	3 years
Aggregate borrowing capacity	$ 4,000
GM Financial [Member]
Debt Instrument [Line Items]
2020 (April 1, 2020 to December 31, 2020)	36,122
2021	23,383
2022(b)	12,839
2023	7,396
2024	5,866
2025	5,003
Thereafter	5,171
Total	$ 95,780

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal, Remainder of Fiscal Year

No definition available.

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal after Year Seven

+ References

No definition available.

+ Details

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal after Year Six

+ References

No definition available.

+ Details

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal in Year Five

+ References

No definition available.

+ Details

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal in Year Four

+ References

No definition available.

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal in Year Three

+ References

No definition available.

+ Details

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- Definition

Long-term Debt and Finance Lease Obligations, Maturities, Repayments of Principal in Year Two

+ References

No definition available.

+ Details

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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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.

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of long-term debt and lease obligation, including portion classified as current.

+ References

No definition available.

+ Details

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