Equipment on Operating Leases (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property Subject to or Available for Operating Lease [Line Items]
Equipment on operating leases, net	$ 44,054		$ 44,054		$ 42,882
Operating Leases, Future Minimum Payments Receivable [Abstract]
Total	13,061		13,061
Vehicles [Member]
Property Subject to or Available for Operating Lease [Line Items]
Equipment on operating leases	55,570		55,570		53,947
Less: accumulated depreciation	(10,826)		(10,826)		(9,959)
Equipment on operating leases, net	44,744		44,744		43,988
Depreciation expense	1,800	$ 1,600	3,700	$ 3,100
Vehicles [Member] | GM Financial [Member]
Property Subject to or Available for Operating Lease [Line Items]
Equipment on operating leases, net	44,054		44,054		$ 42,882
Operating Leases, Future Minimum Payments Receivable [Abstract]
2018	3,650		3,650
2019	5,709		5,709
2020	2,981		2,981
2021	667		667
2022	52		52
Thereafter	$ 2		$ 2