Segment Reporting (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net sales and revenue	$ 16,778		$ 36,060		$ 49,487	$ 70,938
Earnings (loss) before interest and taxes-adjusted	(536)		3,012		714	5,322
Adjustments	(92)		19		(581)	86
Net income (loss) attributable to noncontrolling interests	(22)		(15)		(30)	(27)
Income (loss) before income taxes	(892)		2,927		(249)	5,209
Income tax benefit (expense)	112		(524)		(245)	(661)
Net income (loss)	(780)	$ 286	2,403	$ 2,145	(494)	4,548
Net income (loss) attributable to stockholders	(758)		2,418		(464)	4,575
Equity in net assets of nonconsolidated affiliates	7,724		8,340		7,724	8,340	$ 8,562
Goodwill and intangible assets, net	5,282		5,457		5,282	5,457	5,337
Total assets	237,535		233,737		237,535	233,737	$ 228,037
Depreciation and amortization	3,258		3,396		6,456	7,505
Impairment charges	7		11		117	18
Equity income	212		271		80	685
Brazil [Member] | GM Brazil Indirect Tax Claim [Member]
Segment Reporting Information [Line Items]
Recoveries of indirect taxes			380			1,200
Automotive [Member]
Segment Reporting Information [Line Items]
Automotive interest income	61		106		144	204
Automotive interest expense	(303)		(195)		(496)	(376)
GMNA [Member] | Transformation Activities [Member]
Segment Reporting Information [Line Items]
Pre-tax restructuring costs			361			1,200
GMI [Member] | Brazil [Member] | GM Brazil Indirect Tax Claim [Member]
Segment Reporting Information [Line Items]
Recoveries of indirect taxes			380			1,200
Operating Segments [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	13,361		32,425		42,510	63,686
Earnings (loss) before interest and taxes-adjusted	(553)		2,758		679	4,891
Adjustments	(92)		19		(581)	86
Equity in net assets of nonconsolidated affiliates	6,240		6,894		6,240	6,894
Goodwill and intangible assets, net	3,219		3,429		3,219	3,429
Total assets	124,573		120,347		124,573	120,347
Depreciation and amortization	1,282		1,541		2,684	3,749
Impairment charges	7		11		117	18
Equity income	170		229		13	598
Operating Segments [Member] | GMNA [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	11,604		28,324		37,435	55,689
Earnings (loss) before interest and taxes-adjusted	(101)		3,022		2,093	4,918
Adjustments	0		(336)		0	(1,119)
Equity in net assets of nonconsolidated affiliates	133		82		133	82
Goodwill and intangible assets, net	2,399		2,520		2,399	2,520
Total assets	101,521		114,515		101,521	114,515
Depreciation and amortization	1,127		1,409		2,354	3,478
Impairment charges	0		8		20	15
Equity income	5		2		11	4
Operating Segments [Member] | GMI [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	1,677		4,047		4,957	7,897
Earnings (loss) before interest and taxes-adjusted	(270)		(48)		(821)	(17)
Adjustments	(92)		357		(581)	1,207
Equity in net assets of nonconsolidated affiliates	6,107		6,800		6,107	6,800
Goodwill and intangible assets, net	819		908		819	908
Total assets	21,494		26,681		21,494	26,681
Depreciation and amortization	149		119		315	246
Impairment charges	7		3		97	3
Equity income	165		233		2	607
Operating Segments [Member] | Cruise [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	28		25		53	50
Earnings (loss) before interest and taxes-adjusted	(195)		(279)		(423)	(448)
Adjustments	0		0		0	0
Equity in net assets of nonconsolidated affiliates	0		0		0	0
Goodwill and intangible assets, net	726		670		726	670
Total assets	3,963		4,212		3,963	4,212
Depreciation and amortization	11		7		19	9
Impairment charges	0		0		0	0
Equity income	0		0		0	0
Operating Segments [Member] | GM Financial [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	3,423		3,639		6,984	7,259
Earnings (loss) before interest and taxes-adjusted	226		536		456	895
Adjustments	0		0		0	0
Equity in net assets of nonconsolidated affiliates	1,484		1,446		1,484	1,446
Goodwill and intangible assets, net	1,337		1,358		1,337	1,358
Total assets	111,154		110,711		111,154	110,711
Depreciation and amortization	1,965		1,848		3,753	3,747
Impairment charges	0		0		0	0
Equity income	42		42		67	87
Corporate [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	80		54		118	100
Earnings (loss) before interest and taxes-adjusted	(182)		(216)		(593)	(10)
Adjustments	0		(2)		0	(2)
Equity in net assets of nonconsolidated affiliates	0		12		0	12
Goodwill and intangible assets, net	1		1		1	1
Total assets	43,258		29,597		43,258	29,597
Depreciation and amortization	6		13		15	25
Impairment charges	0		0		0	0
Equity income	0		(6)		0	(13)
Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales and revenue	(34)		(29)		(60)	(57)
Earnings (loss) before interest and taxes-adjusted	(14)		(3)		2	(16)
Adjustments	0		0		0	0
Equity in net assets of nonconsolidated affiliates	0		0		0	0
Goodwill and intangible assets, net	0		0		0	0
Total assets	(2,155)		(1,533)		(2,155)	(1,533)
Depreciation and amortization	0		0		0	0
Impairment charges	0		0		0	0
Equity income	0		0		0	0
Eliminations [Member] | Automotive [Member]
Segment Reporting Information [Line Items]
Equity in net assets of nonconsolidated affiliates	0		0		0	0
Goodwill and intangible assets, net	0		0		0	0
Total assets	(41,700)		(50,446)		(41,700)	(50,446)
Depreciation and amortization	0		0		0	0
Impairment charges	0		0		0	0
Equity income	$ 0		$ 0		$ 0	$ 0