Restructuring and Other Initiatives - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other	$ 269	$ 366	$ 2,493	$ 868
Restructuring payments	$ 763	$ 379	4,702	$ 1,274
GMNA
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other					$ 7,900
Restructuring recoveries			660
Expected future cash impacts			2,700
GMNA \| Impairment and Other Charges
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other					3,200
GMNA \| Contract Termination
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other					4,700
GMNA \| EV Related Write Down
Restructuring Cost and Reserve [Line Items]
Restructuring payments			4,200		$ 400
GMNA \| Additional Net Restructuring Charges
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other			3,600
GMNA \| Ongoing Commercial Negotiations
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other			2,500
GMNA \| Losses on Supply Agreements
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other			1,300
GMNA \| Impaired Emissions Credits
Restructuring Cost and Reserve [Line Items]
Additions, interest accretion, and other			$ 493