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
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	$ 2,867		$ 2,971
Amount 60 days or more past due	107		115
Net credit losses	35	$ 32
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	1,525		1,730
Amount 60 days or more past due	20		22
Net credit losses	5	4
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	1,265		1,155
Amount 60 days or more past due	78		83
Net credit losses	23	16
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	77		86
Amount 60 days or more past due	9		$ 10
Net credit losses	$ 7	$ 12