| **Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) (USD $)In Millions, unless otherwise specified** | Mar. 31, 2015                                                                                                                                                                                                                                            | Dec. 31, 2014                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | $ 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock                                                                                                                                                                                   | $ 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock                                                                                                                                                                                   |
| Mortgage loans                                                                                                                                                                                         | 586us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet                                                                                                                                                                                             | 588us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet                                                                                                                                                                                             |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | 2,560us-gaap_LongTermDebtNoncurrent                                                                                                                                                                                                                      | 2,559us-gaap_LongTermDebtNoncurrent                                                                                                                                                                                                                      |
| Carrying Amount [Member]                                                                                                                                                                               |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                   | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                   |
| Mortgage loans                                                                                                                                                                                         | 586us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                           | 588us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                           |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | 2,560us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                                                    | 2,559us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_CarryingReportedAmountFairValueDisclosureMember                                                                                                                    |
| Estimated Fair Value [Member]                                                                                                                                                                          |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                      | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                      |
| Mortgage loans                                                                                                                                                                                         | 612us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                              | 608us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                              |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | 2,908us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                       | 2,883us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                                                                                                       |
| Level 1 [Member] | Estimated Fair Value [Member]                                                                                                                                                       |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | 0us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember | 0us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |
| Mortgage loans                                                                                                                                                                                         | 0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember           | 0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember           |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | 0us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                      | 0us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                      |
| Level 2 [Member] | Estimated Fair Value [Member]                                                                                                                                                       |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | 0us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember | 0us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |
| Mortgage loans                                                                                                                                                                                         | 0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember           | 0us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember           |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | 2,908us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                  | 2,883us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                  |
| Level 3 [Member] | Estimated Fair Value [Member]                                                                                                                                                       |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| **Financial Assets [Abstract]**                                                                                                                                                                        |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Notes receivable for the issuance of common stock                                                                                                                                                      | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember | 1us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember |
| Mortgage loans                                                                                                                                                                                         | 612us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember         | 608us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember         |
| **Financial Liabilities [Abstract]**                                                                                                                                                                   |                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                     |
| Long term debt                                                                                                                                                                                         | $ 0us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                    | $ 0us-gaap_LongTermDebtNoncurrent/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementBasisAxis= us-gaap_EstimateOfFairValueFairValueDisclosureMember                                    |

| X                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5
+ Details**Name:**us-gaap_LongTermDebtNoncurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(c)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph c -Article 7
+ Details**Name:**us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amounts receivable from officers and directors resulting from the sale of stock to officers or directors before the cash payment is received.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29,30) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 4.E) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 4 -Section E
+ Details**Name:**us-gaap_ReceivableFromOfficersAndDirectorsForIssuanceOfCapitalStock**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |