Clearing Operations (Investment Policy) (Details) - USD ($) $ in Millions |
Sep. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | $ 5,750 | $ 5,664 |
| Restricted Cash and Equivalents | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 3,744 | 4,383 |
| Demand deposits | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 3,011 | 3,616 |
| Central bank certificates | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 733 | 767 |
| Investments | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 2,006 | 1,281 |
| European government debt securities | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 361 | 465 |
| Reverse repurchase agreements | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 1,463 | 610 |
| Multilateral development bank debt securities | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | $ 182 | $ 206 |