Finance Receivables - Allowance for Loan Losses (Details) - Automobile Loan [Member] - Retail Finance Receivables [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 889	$ 765	$ 713
Provision for loan losses	624	742	640
Charge-offs	(1,196)	(1,171)	(1,136)
Recoveries	536	552	542
Foreign currency translation	(9)	1	6
Balance at end of period	$ 844	$ 889	$ 765