v2.4.0.6

Fair Value Measurements - Level 3 Inputs Reconciliation (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2012 | Mar. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | $ 348.1 | $ 241.0
Included in Condensed Consolidated Statements of Income | 3.6 | 1.5
Included in Other Comprehensive Income | 1.0 | (2.5)
Purchases | 61.3 | 40.2
Settlements | (20.2) | (16.9)
Sales | (4.0) | (2.9)
Transfers into Level 3 from Level 2 | 0.9 | 0
Transfers out of Level 3 into Level 2 | (6.1) | 0
Balance at End of Period | 384.6 | 260.4
Fair Value, Level 1 to level 2 Transfers, Amount | 0 | 0
Fair Value, Level 2 to level 1 Transfers, Amount | 0 | 0
Fair Value, Level 1 to level 3 Transfers, Amount | 0 |
Fair Value, Level 3 to level 1 Transfers, Amount | 0 |
Corporate Bonds and Notes [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | 235.1 | 146.2
Included in Condensed Consolidated Statements of Income | 0.1 | 0
Included in Other Comprehensive Income | 0.9 | 1.2
Purchases | 44.8 | 32.4
Settlements | (16.2) | (11.1)
Sales | (0.3) | (0.5)
Transfers into Level 3 from Level 2 | 0.9 |
Transfers out of Level 3 into Level 2 | (6.1) |
Balance at End of Period | 259.2 | 168.2
Redeemable Preferred Stocks [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | 6.1 | 4.5
Included in Condensed Consolidated Statements of Income | 0 | 0
Included in Other Comprehensive Income | 0.2 | 0.9
Purchases | 0 | 0
Settlements | 0 | 0
Sales | 0 | 0
Transfers into Level 3 from Level 2 | 0 |
Transfers out of Level 3 into Level 2 | 0 |
Balance at End of Period | 6.3 | 5.4
Mortgage and Asset-backed [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | 0.3 | 0.4
Included in Condensed Consolidated Statements of Income | 0 | 0
Included in Other Comprehensive Income | 0 | 0
Purchases | 0 | 0
Settlements | 0 | 0
Sales | 0 | 0
Transfers into Level 3 from Level 2 | 0 |
Transfers out of Level 3 into Level 2 | 0 |
Balance at End of Period | 0.3 | 0.4
Preferred and Common Stocks [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | 13.5 | 14.7
Included in Condensed Consolidated Statements of Income | 3.2 | 1.5
Included in Other Comprehensive Income | (1.2) | (2.3)
Purchases | 0.5 | 0.3
Settlements | 0 | 0
Sales | (3.7) | (2.4)
Transfers into Level 3 from Level 2 | 0 |
Transfers out of Level 3 into Level 2 | 0 |
Balance at End of Period | 12.3 | 11.8
Other Equity Interests [Member] |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |
Balance at Beginning of Period | 93.1 | 75.2
Included in Condensed Consolidated Statements of Income | 0.3 | 0
Included in Other Comprehensive Income | 1.1 | (2.3)
Purchases | 16.0 | 7.5
Settlements | (4.0) | (5.8)
Sales | 0 | 0
Transfers into Level 3 from Level 2 | 0 |
Transfers out of Level 3 into Level 2 | 0 |
Balance at End of Period | $ 106.5 | $ 74.6

X
- Definition Fair Value, Level 1 to level 3 Transfers, Amount + References No definition available. + Details
Name: | kmpr_FairValueLevel1ToLevel3TransfersAmount
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair Value, Level 3 to level 1 Transfers, Amount + References No definition available. + Details
Name: | kmpr_FairValueLevel3ToLevel1TransfersAmount
Namespace Prefix: | kmpr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the transfers of assets or liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueLevel1ToLevel2TransfersAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of the transfers of assets or liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bb) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueLevel2ToLevel1TransfersAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in other comprehensive income (a separate component of shareholders' equity). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c(1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Transfers into assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Transfers out of assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
Name: | us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant