| **Long-Term Debt And Lease Obligation (Book Value And Principal Amounts Of Long-Term Debt (Details) - USD ($) $ in Millions** | Dec. 31, 2022 | Dec. 31, 2021 |
|-------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Debt Instrument**                                                                                                           |          |          |
| Book value                                                                                                                    | $ 789         | $ 789         |
| Principal amount                                                                                                              | $ 793         | $ 793         |
| 6.900% Senior Debentures, Due 2028                                                                                            |          |          |
| **Debt Instrument**                                                                                                           |          |          |
| Interest rate                                                                                                                 | 6.90%         | 6.90%         |
| Book value                                                                                                                    | $ 27          | $ 27          |
| Principal amount                                                                                                              | $ 28          | $ 28          |
| 6.920% Senior Debentures, Due 2028                                                                                            |          |          |
| **Debt Instrument**                                                                                                           |          |          |
| Interest rate                                                                                                                 | 6.92%         | 6.92%         |
| Book value                                                                                                                    | $ 391         | $ 391         |
| Principal amount                                                                                                              | $ 391         | $ 391         |
| 6.125% Senior Notes, Due 2034                                                                                                 |          |          |
| **Debt Instrument**                                                                                                           |          |          |
| Interest rate                                                                                                                 | 6.125%        | 6.125%        |
| Book value                                                                                                                    | $ 371         | $ 371         |
| Principal amount                                                                                                              | $ 374         | $ 374         |

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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Face (par) amount of debt instrument at time of issuance.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
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| - 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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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.
+ References
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| X                                                                                                                                                           |
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