Investments - Other Investments Carrying Values (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Loans to Policyholders at Unpaid Principal	$ 283.4us-gaap_LoansInsurancePolicy	$ 275.4us-gaap_LoansInsurancePolicy
Real Estate at Depreciated Cost	160.9us-gaap_RealEstateInvestmentPropertyNet	167.1us-gaap_RealEstateInvestmentPropertyNet
Trading Securities at Fair Value	4.9us-gaap_TradingSecurities	5.0us-gaap_TradingSecurities
Other	0.4kmpr_OtherInvestmentsOther	0.5kmpr_OtherInvestmentsOther
Total Investments	$ 449.6us-gaap_OtherInvestments	$ 448.0us-gaap_OtherInvestments

Amount before allowance of loans made to policy and contract holders using their life insurance contracts' cash value or separate accounts as collateral. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums over and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a)(7))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(e))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph e

-Article 7

Name:	us-gaap_LoansInsurancePolicy
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant