Finance Receivables and Loans, Net - Schedule of Past Due Financing Receivables and Loans Commercial (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	$ 133,229	$ 136,030
Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	32,276	32,745
Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	16,443	18,259
Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	9,088	8,212
Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	6,745	6,274
Total past due | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	57	42
Total past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	37	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	20	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	57	1
90 or more days past due | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	37	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	20	1
Current | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	32,219	32,703
Current | Automotive | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	16,406	18,254
Current | Other | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	9,088	8,177
Current | Commercial real estate | Commercial
Financing Receivable, Past Due [Line Items]
Finance receivables and loans, net	$ 6,725	$ 6,272