| **Fair Value Measurements**           | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 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| **Fair Value Disclosures [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                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| Fair Value Measurements               | FAIR VALUE MEASUREMENTS Fair Value Hierarchy In accordance with accounting guidance for fair value measurements and disclosures, we categorized our financial instruments, based on the priority of the observable and market-based data for the valuation technique used, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices with readily available independent data in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable market inputs (Level 3). When various inputs for measurement fall within different levels of the fair value hierarchy, the lowest observable input that has a significant impact on fair value measurement is used. Our valuation techniques have not changed from those used at December 31, 2012, and ultimately management determines fair value. See our 2012 Annual Report on Form 10-K, Item 8, Note 3, Fair Value Measurements, Page 121, for information on characteristics and valuation techniques used in determining fair value.Fair Value Disclosures for AssetsThe following tables illustrate the fair value hierarchy for those assets measured at fair value on a recurring basis at March 31, 2013, and December 31, 2012. We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2 during the three month and twelve month periods ending March 31, 2013 and December 31, 2012, respectively.(In millions) Quoted prices inactive markets foridentical assets(Level 1) Significant otherobservable inputs (Level 2) Significantunobservableinputs(Level 3) TotalAt March 31, 2013    Fixed maturities, available for sale:        States, municipalities and political subdivisions $— $3,237 $1 $3,238Convertibles and bonds with warrants attached — 27 — 27United States government 8 — — 8Government-sponsored enterprises — 167 — 167Foreign government — 13 — 13Commercial mortgage-backed securities — 39 — 39Corporate securities — 5,674 3 5,677Subtotal 8 9,157 4 9,169Common equities, available for sale 3,675 — — 3,675Preferred equities, available for sale — 124 2 126Taxable fixed maturities separate accounts — 705 — 705Top Hat Savings Plan 11 — — 11Total $3,694 $9,986 $6 $13,686At December 31, 2012        Fixed maturities, available for sale:        States, municipalities and political subdivisions $— $3,288 $1 $3,289Convertibles and bonds with warrants attached — 31 — 31United States government 8 — — 8Government-sponsored enterprises — 164 — 164Foreign government — 3 — 3Commercial mortgage-backed securities — 28 — 28Corporate securities — 5,567 3 5,570Subtotal 8 9,081 4 9,093Common equities, available for sale 3,238 — — 3,238Preferred equities, available for sale — 134 1 135Taxable fixed-maturities separate accounts — 689 — 689Top Hat Savings Plan 9 — — 9Total $3,255 $9,904 $5 $13,164 Each financial instrument that was deemed to have significant unobservable inputs when determining valuation is identified in the following tables by security type with a summary of changes in fair value as of March 31, 2013. Total Level 3 assets continue to be less than 1 percent of financial assets measured at fair value in the condensed consolidated balance sheets. Assets presented in the table below were valued based primarily on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to us.The following tables provide the change in Level 3 assets for the three months ended March 31: (In millions) Corporate fixedmaturities States,municipalitiesand politicalsubdivisionsfixed maturities Preferred     equities TotalBeginning balance, December 31, 2012 $3 $1 $1 $5Total gains or losses (realized/unrealized):        Included in earnings — — — —Included in other comprehensive income — — — —Purchases — — 1 1Sales — — — —Transfers into Level 3 — — — —Transfers out of Level 3 — — — —Ending balance, March 31, 2013 $3 $1 $2 $6         Beginning balance, December 31, 2011 $18 $3 $4 $25Total gains or losses (realized/unrealized):        Included in earnings — — — —Included in other comprehensive income 3 — 2 5Purchases — — 1 1Sales (3) (1) — (4)Transfers into Level 3 1 — — 1Transfers out of Level 3 (3) — — (3)Ending balance, March 31, 2012 $16 $2 $7 $25 With the exception of the Level 3 reconciliation table, additional disclosure for the Level 3 category is not material.Fair Value Disclosure for Assets and Liabilities Not Carried at Fair Value The disclosures below are presented to provide timely information about the effects of current market conditions on financial instruments that are not reported at fair value in our condensed consolidated financial statements. This table summarizes the book value and principal amounts of our long-term debt: (In millions)     Book value Principal amount      March 31, December 31, March 31, December 31,Interest rate Year of issue   2013 2012 2013 20126.900% 1998 Senior debentures, due 2028 $28 $28 $28 $286.920% 2005 Senior debentures, due 2028 391 391 391 3916.125% 2004 Senior notes, due 2034 371 371 374 374    Total $790 $790 $793 $793 The following table shows fair values of our note payable and long-term debt subject to fair value disclosure requirements: (In millions) Quoted prices inactive markets foridentical assets(Level 1) Significant otherobservable inputs (Level 2) Significantunobservableinputs(Level 3) TotalAt March 31, 2013    Note payable $— $104 $— $1046.900% senior debentures, due 2028 — 32 — 326.920% senior debentures, due 2028 — 504 — 5046.125% senior notes, due 2034 — 428 — 428Total $— $1,068 $— $1,068         At December 31, 2012        Note payable $— $104 $— $1046.900% senior debentures, due 2028 — 31 — 316.920% senior debentures, due 2028 — 479 — 4796.125% senior notes, due 2034 — 431 — 431Total $— $1,045 $— $1,045   The following table shows the fair value of our life policy loans, included in other invested assets, subject to fair value disclosure requirements: (In millions) Quoted prices inactive markets foridentical assets(Level 1) Significant otherobservable inputs (Level 2) Significantunobservableinputs(Level 3) TotalAt March 31, 2013    Life policy loans $— $— $48 $48         At December 31, 2012        Life policy loans $— $— $50 $50 Outstanding principal and interest for these life policy loans was $36 million and $37 million at March 31, 2013, and December 31, 2012, respectively. The following table shows fair values of our deferred annuities and structured settlements, included in life policy and investment contract reserves, subject to fair value disclosure requirements: (In millions) Quoted prices inactive markets foridentical assets(Level 1) Significant otherobservable inputs (Level 2) Significantunobservableinputs(Level 3) TotalAt March 31, 2013    Deferred annuities $— $— $898 $898Structured settlements — 235 — 235Total $— $235 $898 $1,133         At December 31, 2012        Deferred annuities $— $— $898 $898Structured settlements — 240 — 240Total $— $240 $898 $1,138Recorded reserves for the deferred annuities and structured settlements were $1.046 billion and $1.043 billion at March 31, 2013, and December 31, 2012, respectively. |

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| - Definition
The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.
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