Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Summary of Loss Sharing Arrangements (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Financing Receivable, Allowance for Credit Loss [Roll Forward] | ||
| Change in estimated partner reimbursements that decreased provision for credit losses | $ 4,068 | $ 2,369 |
| Loss sharing agreements | ||
| Financing Receivable, Allowance for Credit Loss [Roll Forward] | ||
| Estimated reimbursements from partners, beginning of period | 1,103 | 1,010 |
| Amounts due from partners for charged off loans | (173) | (171) |
| Change in estimated partner reimbursements that decreased provision for credit losses | 337 | 251 |
| Estimated reimbursements from partners, end of period | $ 1,267 | $ 1,090 |