Segment Reporting - Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total revenue	$ 3,918	$ 3,498	$ 7,729	$ 6,840
Operating expenses	479	456	937	899
Leased vehicle expenses	972	1,011	2,019	2,050
Provision for loan losses	174	167	378	298
Interest expense	1,485	1,135	2,881	2,134
Equity income	14	37	45	78
Income before income taxes	822	766	1,559	1,537
North America
Segment Reporting Information [Line Items]
Total revenue	3,531	3,170	6,948	6,218
Operating expenses	385	368	754	727
Leased vehicle expenses	949	992	1,973	2,015
Provision for loan losses	150	135	321	249
Interest expense	1,315	995	2,544	1,872
Equity income	0	0	0	0
Income before income taxes	732	679	1,355	1,356
International
Segment Reporting Information [Line Items]
Total revenue	387	328	781	622
Operating expenses	94	88	184	172
Leased vehicle expenses	23	18	46	35
Provision for loan losses	24	32	57	49
Interest expense	170	139	337	262
Equity income	14	37	45	78
Income before income taxes	$ 90	$ 87	$ 204	$ 181