Finance Receivables and Loans, Net - Schedule of Accounts, Notes, Loans and Financing Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	$ 133,485	$ 136,030
Unamortized premiums and discounts and deferred fees and costs	2,300	2,300
Accrued interest receivable	757	839
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	100,831	103,285
Consumer | Automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	83,868	83,757
Consumer | Consumer mortgage finance receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	16,963	17,234
Interest-only mortgage loans	12	12
Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	0	2,294
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	32,654	32,745
Commercial | Automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	16,939	18,259
Commercial | Consumer mortgage finance receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	6,731	6,274
Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables and loans	$ 8,984	$ 8,212