XML 40 R75.htm IDEA: XBRL DOCUMENT v2.4.1.9
Retirement Plans (Narrative) (Details) (USD $)
3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Dec. 31, 2014
Dec. 31, 2013
property
Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths) 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations   100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations 100.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations  
Expected Long Term Rate Of Return On Plan Assets In Future Year In Hundreths     7.75%ftr_ExpectedLongTermRateOfReturnOnPlanAssetsInFutureYearInHundreths    
Pension settlement costs $ 4,000,000us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1 $ 40,000,000us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1   $ 44,163,000us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1  
Capitalization of pension and OPEB expense related to engineering and plant construction     15,000,000ftr_CapitalizationOfPensionAndOpebExpenseRelatedToEngineeringAndPlantConstruction 19,000,000ftr_CapitalizationOfPensionAndOpebExpenseRelatedToEngineeringAndPlantConstruction 16,000,000ftr_CapitalizationOfPensionAndOpebExpenseRelatedToEngineeringAndPlantConstruction
Pension and other postretirement benefit expenses     (18,026,000)us-gaap_PensionAndOtherPostretirementBenefitExpense 37,243,000us-gaap_PensionAndOtherPostretirementBenefitExpense 28,087,000us-gaap_PensionAndOtherPostretirementBenefitExpense
Number of properties contributed       4ftr_DefinedBenefitPlanNumberOfPropertiesContributed  
Contribution of Property       23,422,000us-gaap_ContributionOfProperty  
Lease term of contributed property       15 years  
Plan assets 1,216,525,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets   1,672,707,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets 1,216,525,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets  
Accumulated benefit obligation 1,560,000,000us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation   2,094,000,000us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation 1,560,000,000us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation  
401 (k) Savings Plan employer contributions     21,000,000us-gaap_DefinedContributionPlanCostRecognized 21,000,000us-gaap_DefinedContributionPlanCostRecognized 23,000,000us-gaap_DefinedContributionPlanCostRecognized
Minimum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Estimated Pension And OPEB Expense     85,000,000ftr_EstimatedPensionAndOpebExpense
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Maximum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Estimated Pension And OPEB Expense     105,000,000ftr_EstimatedPensionAndOpebExpense
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
   
Pension Benefits [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Discount rate - used at year end to value obligation (in hundredths) 4.90%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
  4.10%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
4.90%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Expected long-term rate of return on plan assets (in hundredths)     7.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
8.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
7.75%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Increase in obligation due to mortality assumption rate change     66,000,000us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
   
Lump sum pension payments       165,000,000us-gaap_DefinedBenefitPlanSettlementsBenefitObligation
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Settlement threshold       125,000,000ftr_DefinedBenefitPlanSettlementsBenefitObligationThreshold
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Pension settlement costs       44,163,000us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Number of properties contributed       4ftr_DefinedBenefitPlanNumberOfPropertiesContributed
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Contribution of Property       23,000,000us-gaap_ContributionOfProperty
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Lease term of contributed property       15 years  
Contributions to pension plan     83,238,000us-gaap_DefinedBenefitPlanContributionsByEmployer
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
62,290,000us-gaap_DefinedBenefitPlanContributionsByEmployer
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Plan assets 1,216,525,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
  1,672,707,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
1,216,525,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
1,253,666,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Cash contributions to pension plan       39,000,000us-gaap_PensionContributions
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
29,000,000us-gaap_PensionContributions
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
Benefit payments     110,237,000us-gaap_DefinedBenefitPlanBenefitsPaid
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
54,151,000us-gaap_DefinedBenefitPlanBenefitsPaid
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Postretirement Benefits Other Than Pensions (OPEB) [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Increase in obligation due to mortality assumption rate change     24,000,000us-gaap_IncreaseDecreaseInPensionAndPostretirementObligations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Contributions to pension plan     12,170,000us-gaap_DefinedBenefitPlanContributionsByEmployer
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
12,528,000us-gaap_DefinedBenefitPlanContributionsByEmployer
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
 
Plan assets 2,307,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
  73,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
2,307,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
5,055,000us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
Benefit payments     19,310,000us-gaap_DefinedBenefitPlanBenefitsPaid
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
19,447,000us-gaap_DefinedBenefitPlanBenefitsPaid
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
 
Annual rate of increase in the per-capita cost of covered medical benefits (in hundredths)     7.00%us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Annual rate of increase in the per-capita cost of covered medical benefits in 2019 (in hundredths)     5.00%us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Effect on total of service and interest cost components, 1 percentage point increase     1,000,000us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnServiceAndInterestCostComponents
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Effect on postretirement benefit obligation, 1 percentage point increase     35,000,000us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Effect on total of service and interest cost components, 1 percentage point decrease     (1,000,000)us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Effect on postretirement benefit obligation, 1 percentage point decrease     (30,000,000)us-gaap_DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
   
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Minimum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Discount rate - used at year end to value obligation (in hundredths) 4.90%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
  4.10%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
4.90%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Expected long-term rate of return on plan assets (in hundredths)     3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
3.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Maximum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Discount rate - used at year end to value obligation (in hundredths) 5.20%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
  4.20%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
5.20%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
4.20%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Expected long-term rate of return on plan assets (in hundredths)     4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
4.00%us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
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= us-gaap_OtherPensionPlansDefinedBenefitMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
2013 Pension Real Estate Contributions [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Pension Building Contribution Aggregate Annual Rent       $ 2,000,000ftr_PensionBuildingContributionAggregateAnnualRent
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_Pension2013RealEstateContributionsMember
 
Equity Securities [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths) 42.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_EquitySecuritiesMember
  45.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_EquitySecuritiesMember
42.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_EquitySecuritiesMember
 
Equity Securities [Member] | Minimum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     35.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Equity Securities [Member] | Maximum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     55.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
   
Alternative Investments [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths) 13.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_AlternativeInvestmentsMember
  6.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_AlternativeInvestmentsMember
13.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_AlternativeInvestmentsMember
 
Alternative Investments [Member] | Minimum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     5.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_AlternativeInvestmentsMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Alternative Investments [Member] | Maximum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     15.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= ftr_AlternativeInvestmentsMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
   
Debt Securities [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths) 44.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_DebtSecuritiesMember
  47.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_DebtSecuritiesMember
44.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_DebtSecuritiesMember
 
Debt Securities [Member] | Minimum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     35.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Debt Securities [Member] | Maximum [Member]          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Weighted average asset allocation (in hundreths)     55.00%us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember