Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities - Summary of Significant Non-Cash Investing and Financing Activities (Details) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Significant non-cash investing and financing activities | ||
| Other payable issued for agency acquisitions and purchased customer accounts | $ (18) | $ 10 |
| Estimated acquisition earn-out payables issued for agency acquisitions | 8 | 17 |
| Assumed acquisition earn-out payables | 27 | 0 |
| Note receivable recorded in connection with the sale of a business | $ 25 | $ 0 |