| **Benefit Plans (Reconciliation of Level 3 Plan Assets) (Details) - USD ($) $ in Millions** | 12 Months Ended |
|---------------------------------------------------------------------------------------------|-----------------|
||
| Fixed Maturities [Member]                                                                   |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | $ 784           |   |
| Fair value of plan assets at December 31                                                    | 752             | $ 784 |
| Corporate and other bonds [Member]                                                          |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | 465             |   |
| Fair value of plan assets at December 31                                                    | 510             | 465 |
| Total assets [Member]                                                                       |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | 1,332           |   |
| Fair value of plan assets at December 31                                                    | 1,317           | 1,332 |
| Fair Value, Inputs, Level 3 [Member] | Fixed Maturities [Member]                            |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | 10              | 15 |
| Defined Benefit Plan, Actual Return on Plan Assets Still Held                               | 0               | 0 |
| Defined Benefit Plan, Actual Return on Plan Assets Sold During Period                       | 0               | 0 |
| Defined Benefit Plan, Purchases, Sales, and Settlements                                     | 0               | 0 |
| Defined Benefit Plan, Net transfers into (out of) Level 3                                   | 0               | (5) |
| Fair value of plan assets at December 31                                                    | 10              | 10 |
| Fair Value, Inputs, Level 3 [Member] | Corporate and other bonds [Member]                   |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | 10              | 15 |
| Defined Benefit Plan, Actual Return on Plan Assets Still Held                               | 0               | 0 |
| Defined Benefit Plan, Actual Return on Plan Assets Sold During Period                       | 0               | 0 |
| Defined Benefit Plan, Purchases, Sales, and Settlements                                     | 0               | 0 |
| Defined Benefit Plan, Net transfers into (out of) Level 3                                   | 0               | (5) |
| Fair value of plan assets at December 31                                                    | 10              | 10 |
| Fair Value, Inputs, Level 3 [Member] | Total assets [Member]                                |            |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                            |            |   |
| Fair value of plan assets at January 1                                                      | 10              | 15 |
| Defined Benefit Plan, Actual Return on Plan Assets Still Held                               | 0               | 0 |
| Defined Benefit Plan, Actual Return on Plan Assets Sold During Period                       | 0               | 0 |
| Defined Benefit Plan, Purchases, Sales, and Settlements                                     | 0               | 0 |
| Defined Benefit Plan, Net transfers into (out of) Level 3                                   | 0               | (5) |
| Fair value of plan assets at December 31                                                    | $ 10            | $ 10 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Actual return on plan assets, separately identifying the amount related to assets sold during the period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Actual return on plan assets, separately identifying the amount related to assets still held at the reporting date.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02)(A) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920
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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                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase (decrease) in plan assets from purchases, sales and settlement of plan obligations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02)(B) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02)(B) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Transfers in and out of Level 3. For example, transfers due to changes in the observability of significant inputs.
+ References
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| X                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                |
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| X                                                                                                                                                                          |
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