Derivative Financial Instruments - Derivative Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Automotive \| Not Designated as Hedges
Derivative [Line Items]
Derivative notional amount	$ 5,926	$ 3,413
Automotive \| Not Designated as Hedges \| Foreign Currency \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	5,075	2,710
Automotive \| Not Designated as Hedges \| Commodity \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	806	658
Automotive \| Not Designated as Hedges \| PSA Warrants \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	45	45
Automotive \| Not Designated as Hedges \| Fair Value Hedges \| PSA Warrants \| Fair Value Level 2
Derivative [Line Items]
Fair Value of Assets	964	827
GM Financial
Derivative [Line Items]
Derivative notional amount	108,673	113,871
Fair Value of Assets	636	502
Fair Value of Liabilities	519	869
Collateral	210
Collateral available for netting		451
GM Financial \| Designated as Hedges \| Cash Flow Hedges \| Interest Rate Swap \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	590	768
Fair Value of Assets	0	8
Fair Value of Liabilities	6	0
GM Financial \| Designated as Hedges \| Cash Flow Hedges \| Foreign Currency Swaps \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	4,429	2,075
Fair Value of Assets	40	43
Fair Value of Liabilities	119	58
GM Financial \| Designated as Hedges \| Fair Value Hedges \| Interest Rate Swap \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	9,458	9,533
Fair Value of Assets	234	42
Fair Value of Liabilities	23	231
Gain on derivative instruments	355
GM Financial \| Designated as Hedges \| Fair Value Hedges \| Foreign Currency Swaps \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	1,796	1,829
Fair Value of Assets	22	37
Fair Value of Liabilities	71	60
GM Financial \| Not Designated as Hedges \| Interest Rate Contract \| Fair Value Level 2
Derivative [Line Items]
Derivative notional amount	92,400	99,666
Fair Value of Assets	340	372
Fair Value of Liabilities	300	520
Long-term Debt \| GM Financial \| Fair Value Hedges \| Interest Rate Swap
Derivative [Line Items]
Gain on derivative instruments	(569)
PSA Group \| Nonoperating Income (Expense) \| Automotive \| Not Designated as Hedges
Derivative [Line Items]
Gain on derivative instruments	$ 154	$ 116

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.

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

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

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Fair value, after the effects of master netting arrangements, of a financial liability or 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 liabilities not subject to a master netting arrangement and not elected to be offset.

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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.

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Nominal or face amount used to calculate payment on derivative.

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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