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, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	$ 2,908		$ 2,908		$ 2,971
Amount 60 days or more past due	104		104		115
Net credit losses	24	$ 30	59	$ 62
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	1,334		1,334		1,730
Amount 60 days or more past due	18		18		22
Net credit losses	3	4	8	8
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	1,574		1,574		1,155
Amount 60 days or more past due	86		86		83
Net credit losses	21	16	44	32
Whole-loan sales | Other | Consumer
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Total amount	0		0		86
Amount 60 days or more past due	0		0		$ 10
Net credit losses	$ 0	$ 10	$ 7	$ 22