| **Employee Retirement Benefits (Benefit Obligation Activity Using An Actuarial Measurement Date For Qualified Plan And SERP) (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended                                           |
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| **Change in projected benefit obligation:**                                                                                                                                             |                                                      |   |   |
| Benefit obligation, January 1                                                                                                                                                           | $ 284us-gaap_DefinedBenefitPlanBenefitObligation          | $ 320us-gaap_DefinedBenefitPlanBenefitObligation |   |
| Service cost                                                                                                                                                                            | 10us-gaap_DefinedBenefitPlanServiceCost                   | 13us-gaap_DefinedBenefitPlanServiceCost | 12us-gaap_DefinedBenefitPlanServiceCost |
| Interest cost                                                                                                                                                                           | 15us-gaap_DefinedBenefitPlanInterestCost                  | 13us-gaap_DefinedBenefitPlanInterestCost | 14us-gaap_DefinedBenefitPlanInterestCost |
| Actuarial loss (gain)                                                                                                                                                                   | 35us-gaap_DefinedBenefitPlanActuarialGainLoss             | (34)us-gaap_DefinedBenefitPlanActuarialGainLoss |   |
| Benefits paid                                                                                                                                                                           | (27)us-gaap_DefinedBenefitPlanBenefitsPaid                | (28)us-gaap_DefinedBenefitPlanBenefitsPaid |   |
| Other                                                                                                                                                                                   | 2us-gaap_DefinedBenefitPlanOtherCosts                     | 0us-gaap_DefinedBenefitPlanOtherCosts | 0us-gaap_DefinedBenefitPlanOtherCosts |
| Projected benefit obligation, December 31                                                                                                                                               | 319us-gaap_DefinedBenefitPlanBenefitObligation            | 284us-gaap_DefinedBenefitPlanBenefitObligation | 320us-gaap_DefinedBenefitPlanBenefitObligation |
| Accumulated benefit obligation                                                                                                                                                          | 284us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation | 257us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation |   |
| **Change in plan assets:**                                                                                                                                                              |                                                      |   |   |
| Fair value of plan assets, January 1                                                                                                                                                    | 280us-gaap_DefinedBenefitPlanFairValueOfPlanAssets        | 238us-gaap_DefinedBenefitPlanFairValueOfPlanAssets |   |
| Actual return on plan assets                                                                                                                                                            | 30us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets      | 55us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets |   |
| Employer contribution                                                                                                                                                                   | 5us-gaap_DefinedBenefitPlanContributionsByEmployer        | 15us-gaap_DefinedBenefitPlanContributionsByEmployer |   |
| Benefits paid                                                                                                                                                                           | (27)us-gaap_DefinedBenefitPlanBenefitsPaid                | (28)us-gaap_DefinedBenefitPlanBenefitsPaid |   |
| Fair value of plan assets, December 31                                                                                                                                                  | 288us-gaap_DefinedBenefitPlanFairValueOfPlanAssets        | 280us-gaap_DefinedBenefitPlanFairValueOfPlanAssets | 238us-gaap_DefinedBenefitPlanFairValueOfPlanAssets |
| **Unfunded status:**                                                                                                                                                                    |                                                      |   |   |
| Funded status, December 31                                                                                                                                                              | $ (31)us-gaap_DefinedBenefitPlanFundedStatusOfPlan        | $ (4)us-gaap_DefinedBenefitPlanFundedStatusOfPlan |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Accumulated Benefit Obligation -URI http://asc.fasb.org/extlink&oid=6503844Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920
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| - Definition
The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost) -URI http://asc.fasb.org/extlink&oid=6504192Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost) -URI http://asc.fasb.org/extlink&oid=6504226
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.
+ References
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| - Definition
1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date.  2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The increase in the fair value of plan assets from contributions made by the employer.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of other defined benefit plan costs.
+ References
No definition available.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.
+ References
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