XML 82 R72.htm IDEA: XBRL DOCUMENT
v3.23.3

Fair Value Measurements - Quantitative Information for Level 3 Inputs (Details) $ in Millions | Sep. 30, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | ---
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | $ 233.4 | $ 243.2
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 89.4 | 95.9
Equity Securities, FV-NI | 33.1 | 38.4
Fair Value, Equity Securities FV-NI, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Unfunded commitments |  | 192.2
Mezzanine Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 45.8 | 51.6
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 62.8 | 56.0
Senior Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 41.3 | 42.0
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 10.5 | 6.0
Distressed Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 13.0 | 13.0
Secondary Transactions |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 1.7 | 1.7
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 3.1 | 4.2
Hedge Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Leveraged Buyout |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.6 | 0.6
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 7.0 | 9.0
Equity Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 6.7 | 7.9
Real Estate Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Other Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.0
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.0 | 0.2
Alternative Energy Partnership Investments | Variable Interest Entity, Not Primary Beneficiary |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Outstanding commitments to fund equity method limited liability investments | 0.0 | 0.0
Real Estate |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 0.2 | 0.0
Fair Value, Measurements, Recurring |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 6,753.8 | 7,183.0
Total Liabilities | 15.6 | (0.4)
Convertible debt at fair value | 45.9 | 43.3
Derivative Asset |  | 1.7
Fair Value, Measurements, Recurring | Designated as Hedging Instrument |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Derivative Liability | 15.6 |
Derivative Asset |  | (0.4)
Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 193.5 | 189.1
Fair Value, Measurements, Recurring | Other Industries | Preferred Stocks |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 11.7 | 10.8
Fair Value, Measurements, Recurring | Other Industries | Common Stock |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.6 | 1.2
Significant Unobservable Inputs (Level 3) | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Unfunded commitments | 192.7 |
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 197.6 | 230.0
Total Liabilities | 0.0 | 0.0
Convertible debt at fair value | 0.0 | 0.0
Derivative Asset |  | 0.0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Designated as Hedging Instrument |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Derivative Liability | 0.0 | 0.0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.0
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Other Industries | Preferred Stocks |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 3.3 | 1.6
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Other Industries | Common Stock |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.4 | 0.5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 102.3 | 117.0
Total Liabilities | 0.0 | 0.0
Convertible debt at fair value | 0.0 |
Derivative Asset |  | 0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Designated as Hedging Instrument |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Derivative Liability | 0.0 | 0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Other Industries | Preferred Stocks |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Other Industries | Common Stock |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.2 | 0.3
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 6,260.4 | 6,646.9
Derivative Liability | (15.6) | 0.4
Total Liabilities | 15.6 | 0.4
Convertible debt at fair value | 45.9 | 43.3
Derivative Asset |  | 1.7
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Other Industries | Preferred Stocks |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 8.4 | 9.2
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Other Industries | Common Stock |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.4
Fair Value Measured at Net Asset Value Per Share |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 440.1 | 430.7
Equity Method Investments, Fair Value Disclosure | 224.1 | 217.0
Alternative Investment | 193.5 | 189.1
Fair Value, Alternative Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments | 103.3 | 96.3
Equity Securities, FV-NI | 5.3 | 8.3
Fair Value Measured at Net Asset Value Per Share | Mezzanine Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 123.8 | 114.3
Alternative Investment | 121.9 | 106.0
Fair Value Measured at Net Asset Value Per Share | Senior Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 21.7 | 21.6
Alternative Investment | 25.1 | 21.9
Fair Value Measured at Net Asset Value Per Share | Distressed Debt |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 8.0 | 9.4
Alternative Investment | 12.8 | 12.5
Fair Value Measured at Net Asset Value Per Share | Secondary Transactions |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 8.2 | 9.3
Alternative Investment | 2.9 | 3.5
Fair Value Measured at Net Asset Value Per Share | Hedge Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 0.1 | 0.5
Alternative Investment | 3.0 | 18.1
Fair Value Measured at Net Asset Value Per Share | Leveraged Buyout |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 9.9 | 8.9
Alternative Investment | 21.6 | 21.6
Fair Value Measured at Net Asset Value Per Share | Equity Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 1.2 | 1.2
Alternative Investment | 6.1 | 5.4
Fair Value Measured at Net Asset Value Per Share | Real Estate Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 41.6 | 43.3
Fair Value Measured at Net Asset Value Per Share | Other Funds |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 9.6 | 8.5
Alternative Investment | 0.0 | 0.1
Fair Value Measured at Net Asset Value Per Share | Alternative Energy Partnership Investments |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Method Investments, Fair Value Disclosure | 17.2 | 16.3
Fair Value Measured at Net Asset Value Per Share | Real Estate |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Alternative Investment | 0.1 | 0.0
Measured at Net Asset Value | Fair Value, Measurements, Recurring |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Assets | 193.5 | 189.1
Total Liabilities | 0.0 | 0.0
Convertible debt at fair value | 0.0 | 0.0
Derivative Asset |  | 0.0
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Designated as Hedging Instrument |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Derivative Liability | 0.0 | 0.0
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Limited Liability Companies and Limited Partnerships |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 193.5 | 189.1
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Other Industries | Preferred Stocks |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | 0.0 | 0.0
Measured at Net Asset Value | Fair Value, Measurements, Recurring | Other Industries | Common Stock |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Equity Securities, FV-NI, Current | $ 0.0 | $ 0.0
Senior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Minimum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.110 | 0.046
Senior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Maximum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.367 | 0.367
Senior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Weighted-average Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.138 | 0.109
Junior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Minimum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.124 | 0.088
Junior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Maximum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.225 | 0.225
Junior Debt | Measurement Input, Discount Rate | Non-investment-grade | Market Yield | Weighted-average Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Debt instrument, measurement input | 0.146 | 0.151
Private Placement | Investment-grade | Market Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Fair Value | $ 58.7 | $ 56.5
Private Placement | Measurement Input, Discount Rate | Investment-grade | Market Yield | Minimum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Alternative investment, measurement input | 0.042 | 0.046
Private Placement | Measurement Input, Discount Rate | Investment-grade | Market Yield | Maximum | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Alternative investment, measurement input | 0.164 | 0.145
Private Placement | Measurement Input, Discount Rate | Investment-grade | Market Yield | Weighted-average Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Alternative investment, measurement input | 0.096 | 0.092
Senior Debt | Non-investment-grade | Market Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Fair Value | $ 41.9 | $ 72.9
Junior Debt | Non-investment-grade | Market Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Fair Value | 32.2 | 42.1
Other | Market Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Fair Value | 61.1 | 56.4
Investments in Fixed Maturities | Market Yield | Significant Unobservable Inputs (Level 3) |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Total Fair Value | $ 193.9 | $ 227.9

X
- Definition Fair Value, Alternative Investments, Entities That Calculate Net Asset Value, Unfunded Commitments + References No definition available. + Details
Name: | kmpr_FairValueAlternativeInvestmentsEntitiesThatCalculateNetAssetValueUnfundedCommitments
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair Value, Equity Method Investments, Entities That Calculate Net Asset Value, Unfunded Commitments + References No definition available. + Details
Name: | kmpr_FairValueEquityMethodInvestmentsEntitiesThatCalculateNetAssetValueUnfundedCommitments
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair Value, Equity Securities FV-NI, Entities That Calculate Net Asset Value, Unfunded Commitments + References No definition available. + Details
Name: | kmpr_FairValueEquitySecuritiesFVNIEntitiesThatCalculateNetAssetValueUnfundedCommitments
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Outstanding Commitments to Fund Equity Method Limited Liability Investments + References No definition available. + Details
Name: | kmpr_OutstandingCommitmentsToFundEquityMethodLimitedLiabilityInvestments
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 35 -Paragraph 54B -Publisher FASB -URI https://asc.fasb.org//1943274/2147482134/820-10-35-54B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A + Details
Name: | us-gaap_AlternativeInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Value of input used to measure alternative investment. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AlternativeInvestmentMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock. + References No definition available. + Details
Name: | us-gaap_ConvertibleDebtFairValueDisclosures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Value of input used to measure debt instrument, including, but not limited to, convertible and non-convertible debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_DebtInstrumentMeasurementInput
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-12 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480493/946-210-55-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(c)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5C Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(3)(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column A)(Footnote 3)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5C Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5A Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5B Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5B Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 Reference 22: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-22 Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-10 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(e)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)(Footnote 7)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5C Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-04(9)(d)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)(Footnote 8)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5C -Subparagraph (SX 210.12-13C(Column H)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5C Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5 -Subparagraph (SX 210.12-13(Column G)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5A -Subparagraph (SX 210.12-13A(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5A Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5B Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 5B -Subparagraph (SX 210.12-13B(Column E)(Footnote 4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-5B Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483466/210-20-50-3 Reference 22: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-22 Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-10 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of investments accounted under the equity method. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_EquityMethodInvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483467/210-10-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org//1943274/2147482736/825-10-45-1A + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org//1943274/2147482736/825-10-45-1A + Details
Name: | us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-6A + Details
Name: | us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 30 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-30 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 31 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-31 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-32 + Details
Name: | us-gaap_FairValueOptionQuantitativeDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of financial and nonfinancial obligations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_MezzanineDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_SeniorDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_DistressedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_SecondaryTransactionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_HedgeFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_LeveragedBuyoutMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_RealEstateFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_OtherFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=kmpr_AlternativeEnergyPartnershipInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis=us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=srt_PartnershipInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=kmpr_AllIndustriesOtherthanFinanceInsuranceandRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=kmpr_FairValueInputsNetAssetValueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SeniorDebtObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_PrivatePlacementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_SeniorDebtObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |