Finance Receivables - Credit Risk Profile by FICO Score (Details) - Retail Finance Receivables [Member] - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 14,007
2019	14,730
2018	9,619
2017	5,042
2016	2,113
2015	787
Prior	191
Total	$ 46,489	$ 42,268
Percent of portfolio	100.00%
Prime - FICO Score 680 and greater [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 10,305
2019	9,019
2018	6,063
2017	2,774
2016	940
2015	253
Prior	9
Total	$ 29,363
Percent of portfolio	63.20%
Near-prime - FICO Score 620 to 679 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 1,785
2019	2,533
2018	1,574
2017	828
2016	340
2015	138
Prior	25
Total	$ 7,223
Percent of portfolio	15.50%
Sub-prime - FICO Score less than 620 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 1,917
2019	3,178
2018	1,982
2017	1,440
2016	833
2015	396
Prior	157
Total	$ 9,903
Percent of portfolio	21.30%