XML 136 R121.htm IDEA: XBRL DOCUMENT
v3.20.4

Postretirement Benefits Other Than Pensions - Narrative (Details) $ in Millions | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 | Dec. 31, 2020 USD ($) employees | Dec. 31, 2019 | Dec. 31, 2016 USD ($)
Other Postretirement Benefit Plan, Defined Benefit |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Number of retired employees covered | employees |  | 575 |  |
Number of active employees covered | employees |  | 500 |  |
Pre-tax reduction to its accumulated postretirement benefit obligation |  |  |  | $ 11.0
Amounts that will be amortized from AOCI in next fiscal Year |  | $ 2.8 |  |
Estimated future employer contributions in next fiscal year |  | $ 1.3 |  |
Medical Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Health care cost trend rate assumed for next fiscal year |  | 6.50% | 7.50% |
Health care cost trend rate assumed for future years |  | 4.80% | 4.80% |
Prescription Drug Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Health care cost trend rate assumed for next fiscal year |  | 7.50% | 10.00% |
Health care cost trend rate assumed for future years | 4.80% |  | 4.80% |

X
- Definition Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Future Years + References No definition available. + Details
Name: | kmpr_DefinedBenefitPlanHealthCareCostTrendRateAssumedForFutureYears
Namespace Prefix: | kmpr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Other Postretirement Benefit Plan, Number of Active Employees Covered + References No definition available. + Details
Name: | kmpr_OtherPostretirementBenefitPlanNumberOfActiveEmployeesCovered
Namespace Prefix: | kmpr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Other Postretirement Benefit Plan, Number of Retired Employees Covered + References No definition available. + Details
Name: | kmpr_OtherPostretirementBenefitPlanNumberOfRetiredEmployeesCovered
Namespace Prefix: | kmpr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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 No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost (credit) included in accumulated other comprehensive (income) loss expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (s) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedAmortizationNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4587-114921 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanPlanAmendments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=kmpr_MedicalBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=kmpr_PrescriptionDrugBenefitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |