| **Investments (Narrative) (Details) $ in Millions**                                  | 12 Months Ended |
|--------------------------------------------------------------------------------------|-----------------|
||
| **Gain (Loss) on Investments**                                                       |            |   |   |
| Largest single common stock holding                                                  | $ 597           | $ 862 |   |
| Largest equity holdings to total equity portfolio                                    | 6.30%           | 7.90% |   |
| Largest equity holdings to total portfolio                                           | 2.70%           | 3.50% |   |
| Assets Held by Insurance Regulators                                                  | $ 107           | $ 119 |   |
| Collateral at fair value                                                             | 135             | 116 |   |
| Fair Value of Owned Common Equities Held in Trust Account                            | 101             | 84 |   |
| Equity Securities at Fair Value                                                      | 9,841           | 11,315 |   |
| Debt Securities, Available-for-Sale, Allowance for Credit Loss                       | 1               |   |   |
| Changes in Allowance for Credit Losses During Period                                 | $ 1             |   |   |
| Maximum                                                                              |            |   |   |
| **Gain (Loss) on Investments**                                                       |            |   |   |
| Debt Securities, Available-for-Sale, Allowance for Credit Loss                       |            | 0 |   |
| Changes in Allowance for Credit Losses During Period                                 |            | $ 0 |   |
| Fixed Maturities                                                                     |            |   |   |
| **Gain (Loss) on Investments**                                                       |            |   |   |
| Number of securities below 70 percent of amortized cost                              | 49              | 0 | 0 |
| Number Of Impaired Securities Intended to be Sold | security                         | 3               | 5 | 14 |
| Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss 3 | $ 908           | $ 16 | $ 10 |
| Number Of Securities Continuous Unrealized Loss Position | security                  | 3,272           | 278 | 128 |

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Amount of unrealized loss on securities classified as available-for-sale.
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Number of impaired available-for-sale debt securities intended to be sold and written down to fair value
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Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.
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| - Definition
Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
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Amount of investment in marketable security.
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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.
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The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.
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