Investment income before investment expense.

No definition available.

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- Definition

Investment Income, Equity Method Limited Liability Investments

+ References

No definition available.

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- Definition

Investment Income, Fair Value Option Investments

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- Definition

Investment Income. Loans to Policyholders

+ References

No definition available.

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- Definition

Investment Income, Other

+ References

No definition available.

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- Definition

Investment Income, Real Estate

+ References

No definition available.

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- Definition

Investment Income, Short Term Investments

+ References

No definition available.

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- Definition

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

+ 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 210.5-02.3)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 4

-Article 7

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- Definition

Amount of dividend income on nonoperating securities.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(a),(b))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a, b

-Article 5

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- Definition

Amount of expenses related to the generation of investment income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.2)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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-Topic 225

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-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.9)

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- Definition

Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 16

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

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-Subparagraph (SX 210.7-04.2)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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Income From Investments - Net Investment Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investment Income:
Equity Method Limited Liability Investments									$ 9.0	$ 26.4	$ 9.3
Fair Value Option Investments									(0.7)	0	0
Short-term Investments									0.6	0.1	0.2
Real Estate									12.1kmpr_InvestmentIncomeRealEstate	20.8kmpr_InvestmentIncomeRealEstate	27.4kmpr_InvestmentIncomeRealEstate
Loans to Policyholders									20.5	19.8	18.9
Other									0.1kmpr_InvestmentIncomeOther	0kmpr_InvestmentIncomeOther	0.1kmpr_InvestmentIncomeOther
Total Investment Income									328.9kmpr_GrossInvestmentIncome	340.6kmpr_GrossInvestmentIncome	327.7kmpr_GrossInvestmentIncome
Investment Expenses:
Other Investment Expenses									19.8	25.9	31.8
Net Investment Income	93.1us-gaap_NetInvestmentIncome	72.3us-gaap_NetInvestmentIncome	72.6us-gaap_NetInvestmentIncome	71.1us-gaap_NetInvestmentIncome	76.9us-gaap_NetInvestmentIncome	82.4us-gaap_NetInvestmentIncome	74.6us-gaap_NetInvestmentIncome	80.8us-gaap_NetInvestmentIncome	309.1us-gaap_NetInvestmentIncome	314.7us-gaap_NetInvestmentIncome	295.9us-gaap_NetInvestmentIncome
Accrued Investment Income Receivable	65.5				66.7				65.5	66.7
Real Estate Investment [Member]
Investment Expenses:
Other Investment Expenses									11.3	18.3	26.1
Other Investment [Member]
Investment Expenses:
Other Investment Expenses									8.5	7.6	5.7
Fixed Maturities [Member]
Investment Income:
Interest and Dividends on Fixed Maturities									227.4	235.5	246.1
Equity Securities [Member]
Investment Income:
Dividends on Equity Securities									$ 59.9	$ 38.0	$ 25.7