Finance Receivables - Allowance for Loan Losses (Details) - Retail Finance Receivables [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 866	$ 844	$ 889
Provision for loan losses	880	690	624
Charge-offs	(1,149)	(1,218)	(1,196)
Recoveries	537	548	536
Foreign currency translation	20	(2)	(9)
Balance at end of period	1,915	866	$ 844
Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 801
Balance at end of period		$ 801