Equity securities at cost, including available-for sale and trading equity securities

No definition available.

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Namespace Prefix:	kmpr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=kmpr_SeniorNotes6PercentDueNovember302015Member
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Data Type:	na
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- Details

Name:	us-gaap_DebtInstrumentAxis=kmpr_SeniorNotes4.35PercentDueFebruary152025Member
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- Details

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Data Type:	na
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- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=kmpr_SeniorNotes6PercentDueMay152017Member
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Schedule 2 - Parent Company Financial Statements - Balance Sheets (Non-printing) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Feb. 24, 2015	Feb. 27, 2014
Amortized Cost of Fixed Maturity Securities	$ 5,021.6	$ 4,846.8
Senior Notes [Member] \| Senior Notes Payable, 6.00% due 2015 [Member]
Senior Notes Payable, Interest Rate			6.00%
Senior Notes [Member] \| Senior Notes, 4.35 Percent Due February 15, 2025 [Member]
Senior Notes Payable, Interest Rate			4.35%
Subordinated Debt [Member] \| Subordinated Debenture, 7.375 Percent Due 2054 [Member]
Senior Notes Payable, Interest Rate				7.375%
Parent Company [Member]
Amortized Cost of Fixed Maturity Securities	0.3	46.3
Equity Securities at Cost	6.1	5.2
Parent Company [Member] \| Senior Notes [Member] \| Senior Notes Payable, 6.00% due 2017 [Member]
Fair Value of Notes Payable	$ 0.0	$ 365.3
Senior Notes Payable, Interest Rate	0.00%	6.00%
Parent Company [Member] \| Senior Notes [Member] \| Senior Notes, 4.35 Percent Due February 15, 2025 [Member]
Fair Value of Notes Payable	$ 458.1	$ 248.5
Senior Notes Payable, Interest Rate	4.35%	4.35%
Parent Company [Member] \| Subordinated Debt [Member] \| Subordinated Debenture, 7.375 Percent Due 2054 [Member]
Fair Value of Notes Payable	$ 156.5	$ 157.1
Senior Notes Payable, Interest Rate	7.375%	7.375%