| **Benefit Plans (Schedule of estimated amounts to be recognized from Accumulated other comprehensive income into net periodic cost (benefit) during next fiscal year) (Details) $ in Millions** | 12 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
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| Pension Plans, Defined Benefit [Member]                                                                                                                                                         |            |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                |            |
| Amortization of prior service cost (credit) during 2016                                                                                                                                         | $ 0             |
| Amortization of net actuarial (gain) loss during 2016                                                                                                                                           | 37              |
| Total estimated amounts to be recognized during 2016                                                                                                                                            | 37              |
| Other Postretirement Benefit Plan [Member]                                                                                                                                                      |            |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                |            |
| Amortization of prior service cost (credit) during 2016                                                                                                                                         | (2)             |
| Amortization of net actuarial (gain) loss during 2016                                                                                                                                           | 0               |
| Total estimated amounts to be recognized during 2016                                                                                                                                            | $ (2)           |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedBenefitPlanAmountToBeAmortizedFromAccumulatedOtherComprehensiveIncomeLossNextFiscalYear**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| 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.
+ Details**Name:**us-gaap_DefinedBenefitPlanDisclosureLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount included in accumulated other comprehensive income (AOCI) related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedBenefitPlanFutureAmortizationOfGainLoss**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedBenefitPlanFutureAmortizationOfPriorServiceCostCredit**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |