v2.4.0.6

Fair Value Measurements - Quantitative Information for Level Three Inputs (Details) (Market Yield [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Millions, unless otherwise specified | 3 Months Ended
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Mar. 31, 2012
Senior Debt [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Assets, Fair Value Disclosure | 104.2
Senior Debt [Member] | Minimum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 1.30%
Senior Debt [Member] | Maximum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 15.00%
Senior Debt [Member] | Weighted Average [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 6.60%
Junior Debt [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Assets, Fair Value Disclosure | 132.6
Junior Debt [Member] | Minimum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 8.60%
Junior Debt [Member] | Maximum [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 21.50%
Junior Debt [Member] | Weighted Average [Member] |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |
Fair Value Inputs, Discount Rate | 14.50%

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- Details
Name: | kmpr_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | kmpr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References No definition available. + Details
Name: | kmpr_FairValueInputsDiscountRate
Namespace Prefix: | kmpr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Definition This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant