Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Automotive [Member] \| Designated as Hedges [Member]
Derivative [Line Items]
Notional amount, derivative asset	$ 0	$ 909
Automotive [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Foreign Currency [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	0	803
Automotive [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Commodity [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	0	106
Automotive [Member] \| Not Designated as Hedges [Member]
Derivative [Line Items]
Notional amount, derivative asset	3,488	5,544
Notional amount, derivative liability	1,188	651
Automotive [Member] \| Not Designated as Hedges [Member] \| Foreign Currency [Member] \| Fair Value Level 2/3 [Member]
Derivative [Line Items]
Notional amount, derivative asset	2,834	4,483
Notional amount, derivative liability	1,188	470
Automotive [Member] \| Not Designated as Hedges [Member] \| Commodity [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	606	1,061
Notional amount, derivative liability	0	181
Automotive [Member] \| Not Designated as Hedges [Member] \| PSA Warrants [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	48	0
Automotive [Member] \| Not Designated as Hedges [Member] \| Fair Value Hedges [Member] \| PSA Warrants [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Derivative asset	764
GM Financial [Member] \| Designated as Hedges [Member]
Derivative [Line Items]
Notional amount, derivative asset	5,001	3,070
Notional amount, derivative liability	9,860	8,991
GM Financial [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member]
Derivative [Line Items]
Notional amount, derivative asset	3,751	3,070
Notional amount, derivative liability	0	1,291
GM Financial [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Foreign Currency [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	1,574	0
Notional amount, derivative liability	0	791
GM Financial [Member] \| Designated as Hedges [Member] \| Cash Flow Hedges [Member] \| Interest Rate Swaps [Member] \| Fair Value Level 2/3 [Member]
Derivative [Line Items]
Notional amount, derivative asset	2,177	3,070
Notional amount, derivative liability	0	500
GM Financial [Member] \| Designated as Hedges [Member] \| Fair Value Hedges [Member] \| Interest Rate Swaps [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	1,250	0
Notional amount, derivative liability	9,860	7,700
Derivative liability	290	276
GM Financial [Member] \| Not Designated as Hedges [Member]
Derivative [Line Items]
Notional amount, derivative asset	56,782	17,657
Notional amount, derivative liability	26,357	18,316
GM Financial [Member] \| Not Designated as Hedges [Member] \| Foreign Currency [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	1,201	0
GM Financial [Member] \| Not Designated as Hedges [Member] \| Interest Rate Swaps [Member] \| Fair Value Level 2/3 [Member]
Derivative [Line Items]
Notional amount, derivative asset	38,741	7,959
Notional amount, derivative liability	8,404	6,170
Derivative asset	260
GM Financial [Member] \| Not Designated as Hedges [Member] \| Interest Rate Caps and Floors [Member] \| Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative asset	16,840	9,698
Notional amount, derivative liability	$ 17,953	$ 12,146

Nominal or face amount used to calculate payments on the derivative asset.

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