Other Liabilities and Deferred Revenue (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Accounts Payable and Accrued Liabilities, Current [Abstract]
Dealer and dealers’ customer allowances and claims	$ 11,632	$ 13,113
Deferred revenue	2,021	2,091
Employee benefit plans	1,483	1,857
Accrued interest	1,117	1,128
OPEB (a)	327	332
Pension (a)	184	185
Operating lease liabilities	339	367
Other	3,689	3,914
Total current other liabilities and deferred revenue	20,792	22,987
Accounts Payable and Accrued Liabilities, Noncurrent [Abstract]
Pension (a)	9,487	9,878
OPEB (a)	5,661	5,740
Dealer and dealers’ customer allowances and claims	2,464	1,921
Deferred revenue	4,257	4,191
Operating lease liabilities	914	1,047
Employee benefit plans	1,105	1,104
Other	1,503	1,443
Total non-current other liabilities and deferred revenue	25,391	25,324
Net pension assets	$ 3,800	$ 3,200