Finance Receivables - Credit Risk Profile by Dealer grouping of Commercial Finance Receivables (Details) - Commercial Finance Receivables - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving	$ 5,590	$ 7,921
2021	446	581
2020	457	205
2019	145	117
2018	58	127
2017	62	72
Prior	14	57
Total	$ 6,772	$ 9,080
Percent of portfolio	100.00%	100.00%
Floorplan Advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of revolving balance	94.00%	97.00%
I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving	$ 5,296	$ 7,210
2021	433	579
2020	426	179
2019	131	77
2018	57	110
2017	50	43
Prior	10	19
Total	$ 6,403	$ 8,217
Percent of portfolio	94.60%	90.50%
II
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving	$ 213	$ 508
2021	5	2
2020	16	18
2019	12	11
2018	1	15
2017	10	18
Prior	0	34
Total	$ 257	$ 606
Percent of portfolio	3.80%	6.70%
III
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving	$ 81	$ 203
2021	8	0
2020	15	8
2019	2	29
2018	0	2
2017	2	11
Prior	4	0
Total	$ 112	$ 253
Percent of portfolio	1.60%	2.80%
IV
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revolving	$ 0	$ 0
2021	0	0
2020	0	0
2019	0	0
2018	0	0
2017	0	0
Prior	0	4
Total	$ 0	$ 4
Percent of portfolio	0.00%	0.00%