| Line Item | Jun 30, 2026 | Mar 31, 2026 | Dec 31, 2025 | Sep 30, 2025 | Jun 30, 2025 | Mar 31, 2025 | Dec 31, 2024 | Sep 30, 2024 | Jun 30, 2024 | Mar 31, 2024 | Dec 31, 2023 | Sep 30, 2023 | Jun 30, 2023 | Mar 31, 2023 | Dec 31, 2022 | Sep 30, 2022 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Earned Premiums | ||||||||||||||||
| Net Investment Income | ||||||||||||||||
| Other Income | ||||||||||||||||
| Change in Fair Value of Equity and Convertible Securities | ||||||||||||||||
| Net Realized Investment Gains (Losses) | ||||||||||||||||
| Impairment Losses | ||||||||||||||||
| Total Revenues | ||||||||||||||||
| YoY growth | -10.8% | -7.2% | -4.7% | +5.2% | ||||||||||||
| Expenses: | ||||||||||||||||
| Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses | ||||||||||||||||
| Insurance and Other Expenses | ||||||||||||||||
| Interest Expense | ||||||||||||||||
| Goodwill Impairment | — | — | — | |||||||||||||
| Total Expenses | ||||||||||||||||
| (Loss) Income before Income Taxes | ||||||||||||||||
| Income Tax (Benefit) Expense | ||||||||||||||||
| Net (Loss) Income | ||||||||||||||||
| % of revenue | -42.6% | -0.4% | -0.9% | -2.0% | ||||||||||||
| Less: Net Loss attributable to Noncontrolling Interest | ||||||||||||||||
| Net (Loss) Income attributable to Kemper Corporation | ||||||||||||||||
| % of revenue | -42.5% | -0.2% | -0.7% | -1.7% | ||||||||||||
| Net (Loss) Income attributable to Kemper Corporation per Unrestricted Share: | ||||||||||||||||
| Basic (in dollars per share) | — | |||||||||||||||
| Diluted (in dollars per share) | — |