Catastrophe Reinsurance - Coverage for Catastrophe Reinsurance (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property & Casualty Insurance Subsidiaries | Retained
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, reinsured risk, percentage	0.00%	0.00%	0.00%
Property & Casualty Insurance Subsidiaries | 1st Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, percentage	95.00%	95.00%	95.00%
Property & Casualty Insurance Subsidiaries | 2nd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, percentage	95.00%
Property & Casualty Insurance Subsidiaries | 2nd Layer of Coverage (Tranche A)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, percentage		63.30%	31.70%
Property & Casualty Insurance Subsidiaries | 2nd Layer of Coverage (Tranche B)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, percentage		31.70%	63.30%
Property & Casualty Insurance Subsidiaries | Minimum
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, amount retained	$ 0	$ 0
Reinsurance retention policy, excess retention, amount reinsured	60,000,000.0	60,000,000.0
Property & Casualty Insurance Subsidiaries | Minimum | Retained
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, amount retained	0	0	$ 0
Property & Casualty Insurance Subsidiaries | Minimum | 1st Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	50,000,000.0	50,000,000.0	50,000,000.0
Property & Casualty Insurance Subsidiaries | Minimum | 2nd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	150,000,000.0
Property & Casualty Insurance Subsidiaries | Minimum | 2nd Layer of Coverage (Tranche A)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured		150,000,000.0	150,000,000.0
Property & Casualty Insurance Subsidiaries | Minimum | 2nd Layer of Coverage (Tranche B)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured		150,000,000.0	150,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, amount retained	60,000,000.0	60,000,000.0
Reinsurance retention policy, excess retention, amount reinsured	110,000,000.0	110,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum | Retained
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, amount retained	50,000,000.0	50,000,000.0	50,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum | 1st Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	150,000,000.0	150,000,000.0	150,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum | 2nd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	$ 250,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum | 2nd Layer of Coverage (Tranche A)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured		250,000,000.0	250,000,000.0
Property & Casualty Insurance Subsidiaries | Maximum | 2nd Layer of Coverage (Tranche B)
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured		$ 350,000,000.0	$ 350,000,000.0
Kemper Preferred, Kemper Specialty and Kemper Direct Segments | 3rd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, percentage	95.00%
Kemper Preferred, Kemper Specialty and Kemper Direct Segments | Minimum | 3rd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	$ 250,000,000.0
Kemper Preferred, Kemper Specialty and Kemper Direct Segments | Maximum | 3rd Layer of Coverage
Liability for Catastrophe Claims [Line Items]
Reinsurance retention policy, excess retention, amount reinsured	$ 275,000,000.0