Schedule 2 - Parent Company Financial Statements - Balance Sheets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Investments in Subsidiaries	$ 184,800,000	$ 245,100,000
Fixed Maturities at Fair Value (Amortized Cost: 2014 – $12.2)	4,777,600,000	4,575,000,000
Fair Value Option Investments	53,300,000kmpr_FairValueOptionInvestments	0kmpr_FairValueOptionInvestments
Short-term Investments	342,200,000us-gaap_OtherShortTermInvestments	284,700,000us-gaap_OtherShortTermInvestments
Cash	76,100,000us-gaap_Cash	66,500,000us-gaap_Cash	96,300,000us-gaap_Cash	251,200,000us-gaap_Cash
Other Receivables	187,000,000us-gaap_OtherReceivables	193,100,000us-gaap_OtherReceivables
Other Assets	220,200,000us-gaap_OtherAssets	267,400,000us-gaap_OtherAssets
Total Assets	7,833,400,000us-gaap_Assets	7,656,400,000us-gaap_Assets
LIABILITIES AND SHAREHOLDERS’ EQUITY
Notes Payable	752,100,000us-gaap_NotesPayable	606,900,000us-gaap_NotesPayable
Liabilities for Income Taxes	36,500,000kmpr_LiabilitiesForIncomeTaxes	8,300,000kmpr_LiabilitiesForIncomeTaxes
Accrued Expenses and Other Liabilities	409,600,000us-gaap_OtherLiabilities	329,800,000us-gaap_OtherLiabilities
Total Liabilities	5,742,700,000us-gaap_Liabilities	5,604,900,000us-gaap_Liabilities
Shareholders’ Equity:
Additional Paid-in Capital	660,100,000	694,800,000
Retained Earnings	1,202,700,000	1,215,800,000
Accumulated Other Comprehensive Income	222,700,000	135,300,000
Total Shareholders’ Equity	2,090,700,000	2,051,500,000	2,161,700,000	2,116,600,000
Total Liabilities and Shareholders’ Equity	7,833,400,000	7,656,400,000
Parent Company [Member]
ASSETS
Investments in Subsidiaries	2,677,500,000	2,614,000,000
Fixed Maturities at Fair Value (Amortized Cost: 2014 – $12.2)	12,200,000	0
Equity Securities at Fair Value (Cost: 2014 – $21.9; 2013 – $4.7)	21,800,000	5,000,000
Fair Value Option Investments	53,300,000	0
Short-term Investments	225,100,000	130,800,000
Cash	17,900,000	20,800,000	2,200,000	122,400,000
Other Receivables	6,900,000	4,900,000
Current and Deferred Income Taxes	4,700,000	35,000,000
Other Assets	5,600,000	7,300,000
Total Assets	3,025,000,000	2,817,800,000
LIABILITIES AND SHAREHOLDERS’ EQUITY
Liabilities for Income Taxes	14,500,000	90,500,000
Liabilities for Benefit Plans	160,200,000	63,900,000
Accrued Expenses and Other Liabilities	7,500,000	5,000,000
Total Liabilities	934,300,000	766,300,000
Shareholders’ Equity:
Common Stock	5,200,000	5,600,000
Additional Paid-in Capital	660,100,000	694,800,000
Retained Earnings	1,202,700,000	1,215,800,000
Accumulated Other Comprehensive Income	222,700,000	135,300,000
Total Shareholders’ Equity	2,090,700,000	2,051,500,000
Total Liabilities and Shareholders’ Equity	3,025,000,000	2,817,800,000
Parent Company [Member] \| Senior Notes, 6% Due May 15, 2017 [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Notes Payable	358,500,000	357,900,000
Parent Company [Member] \| Senior Notes, 6% Due November 30, 2015 [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Notes Payable	249,500,000	249,000,000
Parent Company [Member] \| Subordinated Debenture, 7.375 Percent Due 2054 [Member]
LIABILITIES AND SHAREHOLDERS’ EQUITY
Notes Payable	$ 144,100,000	$ 0

The sum of (a) Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes and (b) the aggregate tax effects as of the balance sheet date of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws; net of deducting the allocated valuation allowance, if any, to reduce such amount to net realizable value.

No definition available.