Proposed Acquisition of Infinity (Details) - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 13, 2018	Feb. 12, 2018
Business Combination, Separately Recognized Transactions [Line Items]
Cash Amount included in Mixed Consideration		$ 51.60
KMPR Shares included in Mixed Consideration		1.2019
Cash Amount included in Cash Consideration		$ 129.00
KMPR Shares included in Stock Consideration		2.0031
KMPR Shares held by Infinity Shareholders		20.00%
20-trading day weighted average price as of 2-12-18 [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Total Merger Value		$ 1.4
Business Acquisition, Share Price		$ 129.00
Share Price			$ 64.40
Kemper's 2-12-18 Closing Price per share [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Total Merger Value		$ 1.3
Business Acquisition, Share Price		$ 121.01
Share Price			$ 57.75
Infinity [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Premiums Written, Net	$ 1.4