Finance Receivables and Loans, Net - Schedule of Past Due Financing Receivables and Loans Commercial (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	$ 133,485	$ 136,030
Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	32,654	32,745
Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	16,939	18,259
Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	8,984	8,212
Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	6,731	6,274
Total past due | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	3	42
Total past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	2	5
Total past due | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	35
Total past due | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	1	2
30–59 days past due | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	41
30–59 days past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	5
30–59 days past due | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	35
30–59 days past due | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	1
60–89 days past due | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	0
60–89 days past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	0
60–89 days past due | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	0
60–89 days past due | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	0
90 or more days past due | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	3	1
90 or more days past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	2	0
90 or more days past due | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	0	0
90 or more days past due | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	1	1
Current | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	32,651	32,703
Current | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	16,937	18,254
Current | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	8,984	8,177
Current | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	$ 6,730	$ 6,272