Securitizations and Variable Interest Entities - Schedule of Quantitative Information and Net Credit Losses about Securitized and Other Financial Assets Managed Together (Details) - Off-balance sheet variable interest entities - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	$ 3,385		$ 3,385		$ 2,639
Amount 60 days or more past due	91		91		72
Net credit losses	30	$ 11	62	$ 17
Off-balance-sheet securitization entities | Automotive | Consumer
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	2,183		2,183		1,558
Amount 60 days or more past due	16		16		11
Net credit losses	4	0	8	0
Whole-loan sales | Automotive | Consumer
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	1,102		1,102		956
Amount 60 days or more past due	64		64		44
Net credit losses	16	3	32	4
Whole-loan sales | Consumer other | Consumer
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	100		100		125
Amount 60 days or more past due	11		11		$ 17
Net credit losses	$ 10	$ 8	$ 22	$ 13