MODERNIZATION - Schedule of Modernization Expense (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Modernization Costs [Line Items] | ||||
| Modernization | $ 10 | $ 34 | $ 26 | $ 44 |
| Advisory services | ||||
| Modernization Costs [Line Items] | ||||
| Modernization | (1) | 22 | (1) | 31 |
| Implementation Consultants | ||||
| Modernization Costs [Line Items] | ||||
| Modernization | 5 | 7 | 14 | 7 |
| Transition costs | ||||
| Modernization Costs [Line Items] | ||||
| Modernization | 2 | 1 | 5 | 1 |
| Technology | ||||
| Modernization Costs [Line Items] | ||||
| Modernization | 4 | 2 | 8 | 2 |
| Other | ||||
| Modernization Costs [Line Items] | ||||
| Modernization | $ 0 | $ 2 | $ 0 | $ 3 |