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	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	$ 2,971	$ 2,639
Amount 60 days or more past due	115	72
Net credit losses	135	60
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	1,730	1,558
Amount 60 days or more past due	22	11
Net credit losses	20	2
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	1,155	956
Amount 60 days or more past due	83	44
Net credit losses	79	27
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	86	125
Amount 60 days or more past due	10	17
Net credit losses	$ 36	$ 31