Deferred Acquisition Costs and Other Actuarial Balances - Unearned Revenue Liability (Details) - USD ($) $ in Millions |
Sep. 30, 2026 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|---|
| Other Actuarial Balances | |||
| Total unearned revenue liability | $ 549.9 | $ 532.9 | |
| Universal life | Benefits and Protection | Life Insurance | |||
| Other Actuarial Balances | |||
| Total unearned revenue liability | $ 549.9 | $ 532.9 | $ 510.1 |