| **Fair Value Measurements (Details) (USD $)In Millions, unless otherwise specified** | Mar. 31, 2015                                                                                                                                                                                                                       | Dec. 31, 2014                                                                                                                                                                                                                       |
|--------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Level 3                                                                              |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| **Liabilities**                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Guarantees                                                                           | $ 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                       | $ 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                       |
| Recurring basis                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| **Assets**                                                                           |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Derivative financial instruments, net                                                | 88us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                      | 78us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                      |
| Total Assets                                                                         | 88us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                      | 78us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                      |
| **Liabilities**                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Guarantees                                                                           | 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                   | 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                   |
| Total Liabilities                                                                    | 1us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                  | 1us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                  |
| Recurring basis | Level 1                                                            |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| **Assets**                                                                           |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Derivative financial instruments, net                                                | 0us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember  | 0us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember  |
| Total Assets                                                                         | 0us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                  | 0us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                  |
| **Liabilities**                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Guarantees                                                                           | 0us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              | 0us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              |
| Total Liabilities                                                                    | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember             | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember             |
| Recurring basis | Level 2                                                            |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| **Assets**                                                                           |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Derivative financial instruments, net                                                | 88us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember | 78us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember |
| Total Assets                                                                         | 88us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 | 78us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 |
| **Liabilities**                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Guarantees                                                                           | 0us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              | 0us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              |
| Total Liabilities                                                                    | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember             | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember             |
| Recurring basis | Level 3                                                            |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| **Assets**                                                                           |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Derivative financial instruments, net                                                | 0us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember  | 0us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember  |
| Total Assets                                                                         | 0us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                  | 0us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                  |
| **Liabilities**                                                                      |                                                                                                                                                                                                                                |                                                                                                                                                                                                                                |
| Guarantees                                                                           | 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              | 1us-gaap_GuaranteesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember              |
| Total Liabilities                                                                    | $ 1us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           | $ 1us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258
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| X                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of guarantee, including, but not limited to, financial standby letter of credit, fair value guarantee, guarantee of collection of scheduled contractual cash flows from financial assets, and contracts that contingently require the guarantor to make payments or perform services.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12201-110248
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of financial and nonfinancial obligations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258
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| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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