| **Investments (Analysis Of Cost Or Amortized Cost Gross Unrealized Gains And Losses And Fair Value For Investments) (Details) - USD ($) $ in Millions** | Dec. 31, 2018 | Dec. 31, 2017 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Fixed Maturities                                                                                                                                        |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | $ 10,643      | $ 10,314      |
| Gross unrealized gains                                                                                                                                  | 174           | 409           |
| Gross unrealized losses                                                                                                                                 | 128           | 24            |
| Fair value                                                                                                                                              | 10,689        | 10,699        |
| Fixed Maturities | Corporate Securities                                                                                                                 |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 5,712         | 5,420         |
| Gross unrealized gains                                                                                                                                  | 85            | 246           |
| Gross unrealized losses                                                                                                                                 | 87            | 13            |
| Fair value                                                                                                                                              | 5,710         | 5,653         |
| Fixed Maturities | States, Municipalities and Political Subdivisions                                                                                    |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 4,251         | 4,316         |
| Gross unrealized gains                                                                                                                                  | 84            | 155           |
| Gross unrealized losses                                                                                                                                 | 31            | 6             |
| Fair value                                                                                                                                              | 4,304         | 4,465         |
| Fixed Maturities | Commercial Mortgage Backed Securities                                                                                                |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 287           | 280           |
| Gross unrealized gains                                                                                                                                  | 3             | 7             |
| Gross unrealized losses                                                                                                                                 | 2             | 1             |
| Fair value                                                                                                                                              | 288           | 286           |
| Fixed Maturities | Government-Sponsored Enterprises                                                                                                     |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 316           | 257           |
| Gross unrealized gains                                                                                                                                  | 1             | 1             |
| Gross unrealized losses                                                                                                                                 | 7             | 4             |
| Fair value                                                                                                                                              | 310           | 254           |
| Fixed Maturities | United States Government                                                                                                             |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 67            | 31            |
| Gross unrealized gains                                                                                                                                  | 1             | 0             |
| Gross unrealized losses                                                                                                                                 | 1             | 0             |
| Fair value                                                                                                                                              | 67            | 31            |
| Fixed Maturities | Foreign Government                                                                                                                   |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  | 10            | 10            |
| Gross unrealized gains                                                                                                                                  | 0             | 0             |
| Gross unrealized losses                                                                                                                                 | 0             | 0             |
| Fair value                                                                                                                                              | $ 10          | 10            |
| Equity Securities                                                                                                                                       |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  |          | 3,094         |
| Gross unrealized gains                                                                                                                                  |          | 3,169         |
| Gross unrealized losses                                                                                                                                 |          | 14            |
| Fair value                                                                                                                                              |          | 6,249         |
| Equity Securities | Common Equities                                                                                                                     |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  |          | 2,918         |
| Gross unrealized gains                                                                                                                                  |          | 3,135         |
| Gross unrealized losses                                                                                                                                 |          | 14            |
| Fair value                                                                                                                                              |          | 6,039         |
| Equity Securities | Nonredeemable Preferred Equities                                                                                                    |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  |          | 176           |
| Gross unrealized gains                                                                                                                                  |          | 34            |
| Gross unrealized losses                                                                                                                                 |          | 0             |
| Fair value                                                                                                                                              |          | 210           |
| Fixed Maturities And Equity Securities                                                                                                                  |          |          |
| **Schedule of Available-for-sale Securities**                                                                                                           |          |          |
| Cost or amortized cost                                                                                                                                  |          | 13,408        |
| Gross unrealized gains                                                                                                                                  |          | 3,578         |
| Gross unrealized losses                                                                                                                                 |          | 38            |
| Fair value                                                                                                                                              |          | $ 16,948      |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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.
+ References
No definition available.
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| X                                                                                                                                                         |
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| X                                                                                                                                                                             |
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| X                                                                                                                                                                                                    |
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