Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Capitalization, Equity [Line Items]
Preferred Stock, shares authorized	20,000,000
Par value of preferred stock (per share)	$ 0.1
Common stock, shares authorized	100,000,000	100,000,000
Par value of common stock (per share)	$ 0.1	$ 0.1
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares outstanding	64,756,833	51,462,405
Stock Repurchased and retired during period, Shares			(100,000)
Repurchases of common stock			$ (3.8)
Company Action Level RBC, as Percentage of Authorized Control Level RBC	200.00%
Dividends paid	$ 56.4	$ 49.5	49.2
Amount available for dividend payment	911.0
Kemper's Insurance Subsidiaries [Member]
Schedule of Capitalization, Equity [Line Items]
Cash dividends paid by Kemper's Insurance Subsidiaries to Kemper	130.4
Amount available for dividend payments	351.0
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	3,400.0
Life and Health [Member]
Schedule of Capitalization, Equity [Line Items]
Statutory capital and surplus for the Company’s life and health insurance subsidiaries	454.7	414.3
Statutory net income for the Company’s life and health insurance subsidiaries	143.9	84.1	29.7
Statutory capital and surplus required	133.7
Property and Casualty Insurance [Member]
Schedule of Capitalization, Equity [Line Items]
Statutory capital and surplus for the Company’s life and health insurance subsidiaries	1,449.6	855.3
Statutory net income for the Company’s life and health insurance subsidiaries	236.4	$ 56.9	$ 1.4
Statutory capital and surplus required	$ 595.1