Finance Receivables - Delinquency (Details) - Retail Finance Receivables [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Financing receivable past due	$ 1,896	$ 1,896
Financing receivable past due (percent)	4.50%	4.70%
In repossession	$ 44	$ 44
In repossession of contractual amount due (percent)	0.10%	0.10%
Financing receivable and in repossession past due	$ 1,940	$ 1,940
Financing receivable and in repossession past due (percent)	4.60%	4.80%
31 to 60 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable past due	$ 1,354	$ 1,349
Financing receivable past due (percent)	3.20%	3.30%
Greater Than 60 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing receivable past due	$ 542	$ 547
Financing receivable past due (percent)	1.30%	1.40%