| **Investments (Narrative) (Details) - USD ($)**                                             | 3 Months Ended  | 9 Months Ended |                 |
|---------------------------------------------------------------------------------------------|-----------------|----------------|-----------------|
||
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments | $ 2,559,000,000 |           | $ 2,559,000,000 |   | $ 2,198,000,000 |
| Notional value                                                                              | 193,000,000     |           | 193,000,000     |   | 182,000,000 |
| Derivative liability, fair value, gross liability                                           | (16,000,000)    |           | (16,000,000)    |   | $ (7,000,000) |
| Commitments to purchase or fund privately placed debt securities                            | 1,170,000,000   |           | 1,170,000,000   |   |   |
| Commitments to sell various privately placed debt securities                                | 55,000,000      |           | 55,000,000      |   |   |
| Common Stock                                                                                |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Equity securities, FV-NI, gain (loss)                                                       | (4,000,000)     | $ (5,000,000)  | (9,000,000)     | $ (26,000,000) |   |
| Preferred stock                                                                             |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Equity securities, FV-NI, gain (loss)                                                       | (25,000,000)    | (7,000,000)    | 44,000,000      | (60,000,000) |   |
| Fixed maturity securities                                                                   |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Interest receivable                                                                         | 390,000,000     |           | 390,000,000     |   |   |
| Mortgage loans                                                                              |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Interest receivable                                                                         | 4,000,000       |           | 4,000,000       |   |   |
| Senior Notes | 5.750%, face amount of $400, due August 15, 2021                             |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Realized investment gains (losses)                                                          | (20,000,000)    |           | (20,000,000)    |   |   |
| Face amount                                                                                 | $ 400,000,000   |           | $ 400,000,000   |   |   |
| Senior Notes | 5.875%, face amount of $500, due August 15, 2020                             |            |           |            |   |   |
| **Gain (Loss) on Securities [Line Items]**                                                  |            |           |            |   |   |
| Realized investment gains (losses)                                                          |            |           |            | 21,000,000 |   |
| Face amount                                                                                 |            | $ 500,000,000  |            | $ 500,000,000 |   |

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Face (par) amount of debt instrument at time of issuance.
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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.
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Nominal or face amount used to calculate payment on derivative.
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