Segment Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	4
Net financing revenue and other interest income (loss)	$ 6,850	$ 6,167	$ 4,703
Other revenue	1,578	2,039	1,983
Total net revenue	8,428	8,206	6,686
Provision for credit losses	1,399	241	1,439
Total noninterest expense	4,687	4,110	3,833
Income from continuing operations before income tax expense	2,342	3,855	1,414
Total assets	191,826	182,114	182,165
Net financing revenue and other interest income after the provision for credit losses	5,500	5,900	3,300
Automotive Finance operations
Segment Reporting Information [Line Items]
Other revenue	306	251	204
Insurance operations
Segment Reporting Information [Line Items]
Other revenue	1,023	1,345	1,334
Mortgage Finance operations
Segment Reporting Information [Line Items]
Other revenue	27	94	102
Corporate Finance operations
Segment Reporting Information [Line Items]
Other revenue	122	128	45
Operating Segments | Automotive Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income (loss)	5,224	5,209	4,284
Other revenue	306	251	204
Total net revenue	5,530	5,460	4,488
Provision for credit losses	1,036	53	1,236
Total noninterest expense	2,244	2,023	1,967
Income from continuing operations before income tax expense	2,250	3,384	1,285
Total assets	111,463	103,653	104,794
Operating Segments | Insurance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income (loss)	89	59	42
Other revenue	1,023	1,345	1,334
Total net revenue	1,112	1,404	1,376
Provision for credit losses	0	0
Total noninterest expense	1,150	1,061	1,092
Income from continuing operations before income tax expense	(38)	343	284
Total assets	8,659	9,381	9,137
Operating Segments | Mortgage Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income (loss)	221	124	118
Other revenue	27	94	102
Total net revenue	248	218	220
Provision for credit losses	3	(1)	7
Total noninterest expense	190	187	160
Income from continuing operations before income tax expense	55	32	53
Total assets	19,529	17,847	14,889
Operating Segments | Corporate Finance operations
Segment Reporting Information [Line Items]
Net financing revenue and other interest income (loss)	334	308	299
Other revenue	122	128	45
Total net revenue	456	436	344
Provision for credit losses	43	38	149
Total noninterest expense	131	116	107
Income from continuing operations before income tax expense	282	282	88
Total assets	10,544	7,950	6,108
Corporate and Other
Segment Reporting Information [Line Items]
Net financing revenue and other interest income (loss)	982	467	(40)
Other revenue	100	221	298
Total net revenue	1,082	688	258
Provision for credit losses	317	151	47
Total noninterest expense	972	723	507
Income from continuing operations before income tax expense	(207)	(186)	(296)
Total assets	$ 41,631	$ 43,283	$ 47,237