Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Earned Premiums (Changes in Deferred Profit Liability for the Nine and Three Months Ended: 2023 - $51.6 and $15.9; 2022 - $56.8 and $19.1)	$ 1,117.8	$ 1,290.9	$ 3,465.6	$ 3,948.5
Net Investment Income	107.0	97.8	315.1	316.3
Change in Value of Alternative Energy Partnership Investments	0.8	0.4	2.3	(21.2)
Other Income	2.4	4.0	5.3	7.3
Income (Loss) from Change in Fair Value of Equity and Convertible Securities	2.8	(11.2)	6.9	(79.9)
Net Realized Investment (Losses) Gains	(30.3)	(12.1)	(38.3)	0.4
Impairment Gains (Losses)	(1.1)	(8.3)	0.1	(22.1)
Total Revenues	1,199.4	1,361.5	3,757.0	4,149.3
Expenses:
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses (Changes in Liability for Future Policyholder Benefits for the Nine and Three Months Ended: 2023 - $8.6 and $6.1; 2022 - $21.9 and $1.6)	975.2	1,085.3	3,011.9	3,359.6
Insurance Expenses	259.0	300.5	794.4	913.0
Loss from Early Extinguishment of Debt	0.0	0.0	0.0	3.7
Interest and Other Expenses	156.0	63.5	311.7	171.1
Goodwill Impairment	0.0	0.0	49.6	0.0
Total Expenses	1,390.2	1,449.3	4,167.6	4,447.4
Loss before Income Taxes	(190.8)	(87.8)	(410.6)	(298.1)
Income Tax Benefit	44.4	13.0	87.0	64.8
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	(146.4)	(74.8)	(323.6)	(233.3)
Less: Net Loss attributable to Noncontrolling Interest	(0.1)	0.0	(0.1)	0.0
Net Loss attributable to Kemper Corporation	$ (146.3)	$ (74.8)	$ (323.5)	$ (233.3)
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ (2.28)	$ (1.17)	$ (5.05)	$ (3.66)
Diluted (in dollars per share)	$ (2.28)	$ (1.17)	$ (5.05)	$ (3.66)