| **Condensed Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Millions** | Sep. 30, 2020 | Dec. 31, 2019 |
|-------------------------------------------------------------------------------------|---------------|---------------|
| **Investments:**                                                                    |          |          |
| Fixed maturities securities at amortized cost                                       | $ 38,969      | $ 38,126      |
| Marketable securities, fixed maturities, amortized cost                             | 47            | 0             |
| Equity securities at cost                                                           | 927           | 820           |
| Mortgage loans on real estate, commercial and consumer, allowance for credit loss   | 21            | 0             |
| Allowance for uncollectible reinsurance                                             | 24            | 25            |
| Allowance for uncollectible insurance receivables                                   | 32            | 32            |
| Accumulated depreciation on property and equipment                                  | 224           | 215           |
| **Liabilities**                                                                     |          |          |
| Due to related parties                                                              | 47            | 21            |
| Due from related parties                                                            | $ 0           | $ 21          |
| **Stockholders' Equity**                                                            |          |          |
| Common stock, par value (in usd per share)                                          | $ 2.50        | $ 2.50        |
| Common stock, shares authorized (in shares)                                         | 500,000,000   | 500,000,000   |
| Common stock, shares issued (in shares)                                             | 273,040,243   | 273,040,243   |
| Common stock, shares outstanding (in shares)                                        | 271,387,058   | 271,412,591   |
| Treasury stock, shares (in shares)                                                  | 1,653,185     | 1,627,652     |

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