| **Property Transactions Property Transactions - Discontinued Operations (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended |
|------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Business Combinations [Abstract]**                                                                                               |            |   |   |
| Oil and Gas Sales                                                                                                                  | $ 37            | $ 208 | $ 357 |
| Income Before Income Taxes                                                                                                         | 12              | 101 | 215 |
| Income Tax Expense                                                                                                                 | 6               | 55 | 174 |
| Operating Income, Net of Tax                                                                                                       | 6               | 46 | 41 |
| Gain on Sale, Net of Tax                                                                                                           | 65              | 16 | 0 |
| Discontinued Operations, Net of Tax                                                                                                | $ 71            | $ 62 | $ 41 |

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| - Definition
Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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| - Definition
Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.
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| - Definition
Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.
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