Collateralized Agreements - Remaining Contractual Maturity (Details) - U.S Treasury securities and other - Asset Pledged as Collateral - Securities sold under agreements to repurchase - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Collateral in the Form of Securities Pledged [Line Items] | ||
| Financial Instruments, Owned, at Fair Value | $ 6,019 | $ 6,459 |
| Overnight and continuous | ||
| Collateral in the Form of Securities Pledged [Line Items] | ||
| Financial Instruments, Owned, at Fair Value | 4,791 | 0 |
| 30 days or less | ||
| Collateral in the Form of Securities Pledged [Line Items] | ||
| Financial Instruments, Owned, at Fair Value | 479 | 6,459 |
| After 30 days through 90 days | ||
| Collateral in the Form of Securities Pledged [Line Items] | ||
| Financial Instruments, Owned, at Fair Value | 749 | 0 |
| Greater than 90 days | ||
| Collateral in the Form of Securities Pledged [Line Items] | ||
| Financial Instruments, Owned, at Fair Value | $ 0 | $ 0 |