MODERNIZATION - Schedule of Modernization Expense (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Modernization Costs [Line Items] | ||
| Modernization | $ 16 | $ 10 |
| Advisory services | ||
| Modernization Costs [Line Items] | ||
| Modernization | 0 | 9 |
| Implementation Consultants | ||
| Modernization Costs [Line Items] | ||
| Modernization | 9 | 0 |
| Transition costs | ||
| Modernization Costs [Line Items] | ||
| Modernization | 3 | 0 |
| Technology | ||
| Modernization Costs [Line Items] | ||
| Modernization | 4 | 0 |
| Other | ||
| Modernization Costs [Line Items] | ||
| Modernization | $ 0 | $ 1 |