Derivative Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Automotive [Member] | Not Designated as Hedges [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	$ 5,137	$ 5,137	$ 4,676
Automotive [Member] | Not Designated as Hedges [Member] | PSA Group [Member] | Interest Income and Other Non-Operating Income, Net [Member]
Derivative [Line Items]
Gains on derivative instruments	27	153
Automotive [Member] | Not Designated as Hedges [Member] | Fair Value Level 2 [Member] | PSA Group [Member] | Other assets [Member]
Derivative [Line Items]
Fair value of derivative instruments	888	888	764
Automotive [Member] | Not Designated as Hedges [Member] | Foreign Currency [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	4,459	4,459	4,022
Automotive [Member] | Not Designated as Hedges [Member] | Commodity [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	632	632	606
Automotive [Member] | Not Designated as Hedges [Member] | PSA Warrants [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	46	46	48
GM Financial [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	106,021	106,021	98,000
GM Financial [Member] | Designated as Hedges [Member] | Cash Flow Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	1,108	1,108	2,177
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 financial instruments	2,122	2,122	1,574
GM Financial [Member] | Designated as Hedges [Member] | Fair Value Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	11,154	11,154	11,110
GM Financial [Member] | Designated as Hedges [Member] | Fair Value Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member] | Other liabilities [Member]
Derivative [Line Items]
Fair value of derivative instruments	460	460	290
GM Financial [Member] | Not Designated as Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	89,753	89,753	81,938
GM Financial [Member] | Not Designated as Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member] | Other liabilities [Member]
Derivative [Line Items]
Fair value of derivative instruments	563	563	207
GM Financial [Member] | Not Designated as Hedges [Member] | Interest Rate Contract [Member] | Fair Value Level 2 [Member] | Other assets [Member]
Derivative [Line Items]
Fair value of derivative instruments	534	534	329
GM Financial [Member] | Not Designated as Hedges [Member] | Foreign Currency [Member] | Fair Value Level 2 [Member]
Derivative [Line Items]
Notional amount, derivative financial instruments	$ 1,884	$ 1,884	$ 1,201