Segment Reporting - Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Total revenue	$ 3,498	$ 3,146	$ 6,840	$ 6,302
Operating expenses	456	393	899	766
Leased vehicle expenses	1,011	856	2,050	1,711
Provision for loan losses	167	198	298	320
Interest expense	1,135	642	2,134	1,219
Equity income	37	50	78	104
Income before income taxes	766	1,106	1,537	2,390
North America Segment
Segment Reporting Information [Line Items]
Total revenue	3,170	2,904	6,218	5,834
Operating expenses	368	315	727	618
Leased vehicle expenses	992	842	2,015	1,685
Provision for loan losses	135	170	249	268
Interest expense	995	560	1,872	1,067
Equity income	0	0	0	0
Income before income taxes	679	1,017	1,356	2,197
International Segment
Segment Reporting Information [Line Items]
Total revenue	328	242	622	468
Operating expenses	88	79	172	148
Leased vehicle expenses	18	13	35	26
Provision for loan losses	32	28	49	52
Interest expense	139	82	262	152
Equity income	37	50	78	104
Income before income taxes	$ 87	$ 89	$ 181	$ 194