| **Consolidated Statements of Comprehensive Income (USD $)In Millions, unless otherwise specified** | 12 Months Ended                                                                                    |
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| **Statement of Comprehensive Income [Abstract]**                                                   |                                                                                               |   |   |
| Net Income                                                                                         | $ 1,214us-gaap_NetIncomeLoss                                                                       | $ 978us-gaap_NetIncomeLoss | $ 1,027us-gaap_NetIncomeLoss |
| **Other Items of Comprehensive Income (Loss)**                                                     |                                                                                               |   |   |
| Net Change in Pension and Other                                                                    | 42us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax | (6)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax | (20)us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax |
| Less Tax (Benefit)                                                                                 | (15)us-gaap_OtherComprehensiveIncomeLossTax                                                        | 2us-gaap_OtherComprehensiveIncomeLossTax | 7us-gaap_OtherComprehensiveIncomeLossTax |
| Other Comprehensive Income (Loss)                                                                  | 27us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent                          | (4)us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent | (13)us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent |
| Comprehensive Income                                                                               | $ 1,241us-gaap_ComprehensiveIncomeNetOfTax                                                         | $ 974us-gaap_ComprehensiveIncomeNetOfTax | $ 1,014us-gaap_ComprehensiveIncomeNetOfTax |

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| - Definition
Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.
+ References
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| - Definition
The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after tax of other comprehensive income (loss) attributable to parent entity.
+ References
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| - Definition
Amount before tax, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.
+ References
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| - Definition
Amount of tax expense (benefit) allocated to other comprehensive income (loss).
+ References
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