| **Investments**            | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            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| **Investments [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 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| Investments                | INVESTMENTS The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our invested assets:(In millions) Cost or        amortized Gross unrealized FairAt June 30, 2013 cost gains losses valueFixed maturities:        States, municipalities and political subdivisions $3,044 $162 $18 $3,188Convertibles and bonds with warrants attached 16 — — 16United States government 7 — — 7Government-sponsored enterprises 208 — 13 195Foreign government 10 — — 10Commercial mortgage-backed securities 63 — 3 60Corporate securities 5,080 459 23 5,516Subtotal 8,428 621 57 8,992Equity securities:        Common equities 2,375 1,398 12 3,761Preferred equities 77 37 — 114Subtotal 2,452 1,435 12 3,875Total $10,880 $2,056 $69 $12,867At December 31, 2012        Fixed maturities:        States, municipalities and political subdivisions $3,040 $250 $1 $3,289Convertibles and bonds with warrants attached 31 — — 31United States government 7 1 — 8Government-sponsored enterprises 164 — — 164Foreign government 3 — — 3Commercial mortgage-backed securities 27 1 — 28Corporate securities 4,950 622 2 5,570Subtotal 8,222 874 3 9,093Equity securities:        Common equities 2,270 977 9 3,238Preferred equities 99 37 1 135Subtotal 2,369 1,014 10 3,373Total $10,591 $1,888 $13 $12,466 The net unrealized investment gains in our fixed-maturity portfolio are primarily the result of the current low interest rate environment that increased the fair value of our fixed-maturity portfolio. The three largest net unrealized investment gains in our common stock portfolio are from Exxon Mobil Corporation (NYSE:XOM), Chevron Corporation (NYSE:CVX) and The Procter & Gamble Company (NYSE:PG), which had a combined net gain position of $283 million. At At June 30, 2013, we had $16 million fair value of hybrid securities included in fixed maturities that follow Accounting Standards Codification (ASC) 815-15-25, Accountingfor Certain Hybrid Financial Instruments, compared with $31 million fair value of hybrid securities at December 31, 2012. The hybrid securities are carried at fair value, and the changes in fair value are included in realized investment gains and losses. The table below provides fair values and unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss position:(In millions) Less than 12 months 12 months or more Total  Fair Unrealized Fair Unrealized Fair UnrealizedAt June 30, 2013 value losses value losses value lossesFixed maturities:            States, municipalities and political    subdivisions $377 $18 $— $— $377 $18United States government 1 — — — 1 —Foreign government 10 — — — 10 —Government-sponsored enterprises 185 13 — — 185 13Commercial mortgage-backed securities 51 3 — — 51 3Corporate securities 580 22 13 1 593 23Subtotal 1,204 56 13 1 1,217 57Equity securities:            Common equities 202 12 — — 202 12Preferred equities 4 — — — 4 —Subtotal 206 12 — — 206 12Total $1,410 $68 $13 $1 $1,423 $69At December 31, 2012            Fixed maturities:            States, municipalities and political    subdivisions $53 $1 $— $— $53 $1Government-sponsored enterprises 1 — — — 1 —Corporate securities 58 1 17 1 75 2Subtotal 112 2 17 1 129 3Equity securities:            Common equities 107 9 — — 107 9Preferred equities 4 1 — — 4 1Subtotal 111 10 — — 111 10Total $223 $12 $17 $1 $240 $13 The following table provides investment income, realized investment gains and losses and the change in unrealized investment gains and losses and other items:(In millions) Three months ended June 30, Six months ended June 30,  2013 2012 2013 2012Investment income summary:        Interest on fixed maturities $103 $106 $205 $212Dividends on equity securities 30 27 57 53Other investment income  — 1 1 2Total 133 134 263 267Less investment expenses 2 2 4 4Total $131 $132 $259 $263         Realized investment gains and losses summary:        Fixed maturities:        Gross realized gains $2 $13 $4 $16Gross realized losses — — — —Other-than-temporary impairments — — (2) —Equity securities:        Gross realized gains 12 6 49 29Gross realized losses — (1) — (1)Other-than-temporary impairments — (14) — (30)Securities with embedded derivatives — 1 1 5Other — 1 3 —Total $14 $6 $55 $19         Change in unrealized gains and losses summary:        Fixed maturities $(282) $29 $(307) $78Equity securities 38 (82) 419 97Adjustment to deferred acquisition costs and life policy reserves 26 (8) 29 (15)Amortization of pension actuarial loss and prior service cost 3 1 5 3Other (2) 3 (5) 5Income taxes on above 76 20 (49) (59)Total $(141) $(37) $92 $109 During the three and six months ended June 30, 2013 and 2012, there were no credit losses on fixed-maturity securities for which a portion of other-than-temporary impairment (OTTI) has been recognized in other comprehensive income. During the quarter ended June 30, 2013, there were no other-than-temporarily impaired securities. At June 30, 2013, four fixed-maturity investments with a total unrealized loss of $1 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below 70 percent of amortized cost. There were no equity investments in an unrealized loss position for 12 months or more as of June 30, 2013. At December 31, 2012, four fixed-maturity investments with a total unrealized loss of $1 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below 70 percent of amortized cost. There were no equity investments in an unrealized loss position for 12 months or more as of December 31, 2012. |

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| - Definition
The entire disclosure for  investments in certain debt and equity securities.
+ References
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