Clearing Operations (Investment Policy) (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | $ 2,323 | $ 5,842 |
| Restricted cash and cash equivalents | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 254 | 3,120 |
| Demand deposits | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 233 | 3,011 |
| Central bank certificates | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 21 | 109 |
| Investments | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 2,069 | 2,722 |
| European government debt securities | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 337 | 292 |
| Reverse repurchase agreements | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | 1,514 | 2,245 |
| Multilateral development bank debt securities | ||
| Clearing Operations [Line Items] | ||
| Default funds and margin deposits assets | $ 218 | $ 185 |