| **Postretirement Benefits - Components of Postretirement Benefits Expense Included in Consolidated Statements of Operations (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
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| **Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]**                                                                                         |            |   |   |
| Total postretirement benefits expense                                                                                                                                                  | $ 177           | $ 203 | $ 169 |
| Pension Plan, Defined Benefit [Member]                                                                                                                                                 |            |   |   |
| **Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]**                                                                                         |            |   |   |
| Total postretirement benefits expense                                                                                                                                                  | 116             | 122 | 139 |
| Other Postretirement Benefit Plan, Defined Benefit [Member]                                                                                                                            |            |   |   |
| **Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]**                                                                                         |            |   |   |
| Total postretirement benefits expense                                                                                                                                                  | $ 61            | $ 81 | $ 30 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
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| - Definition
The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.
+ 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 (h) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920
+ Details**Name:**us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                |
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| - Details**Name:**us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |