Other Liabilities and Deferred Revenue (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Accounts Payable and Accrued Liabilities, Current [Abstract]
Dealer and dealers’ customer allowances and claims	$ 11,989	$ 11,369
Deferred revenue	2,732	2,095
Employee benefit plans	2,097	1,755
Accrued interest	1,046	988
OPEB (a)	342	339
Pension (a)	203	204
Operating lease liabilities	327	0
Other	3,767	3,806
Total current other liabilities and deferred revenue	22,503	20,556
Accounts Payable and Accrued Liabilities, Noncurrent [Abstract]
Pension (a)	9,061	9,423
OPEB (a)	5,224	5,220
Dealer and dealers’ customer allowances and claims	2,163	2,497
Deferred revenue	4,184	3,985
Operating lease liabilities	1,013	0
Employee benefit plans	1,125	1,080
Other	1,262	1,383
Total non-current other liabilities and deferred revenue	24,032	23,588
Net pension assets	$ 3,600	$ 3,300