v2.4.1.9
Retirement Plans (Details 7) (Pension [Member], USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Retirement Plans [Line Items]      
Fair value of plan assets $ 3,654us-gaap_DefinedBenefitPlanFairValueOfPlanAssets $ 3,429us-gaap_DefinedBenefitPlanFairValueOfPlanAssets $ 2,875us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Temporary Cash Investments [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Registered Investment Companies [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 294us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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U.S. Government Securities [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 163us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Corporate Bonds & Debentures [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 381us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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= us-gaap_PensionPlansDefinedBenefitMember		  
Corporate Stock [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 1,091us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Venture Capital And Buyout Partnerships [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 234us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Real Estate Partnerships [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 139us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Common Trust And Other Funds [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 1,340us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Other Assets - Pension Plan [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets (10)us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 1,110us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Temporary Cash Investments [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 22us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Registered Investment Companies [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 12us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | U.S. Government Securities [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Corporate Bonds & Debentures [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Corporate Stock [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 1,076us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Venture Capital And Buyout Partnerships [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Real Estate Partnerships [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Quoted Prices in Active Markets for Identical Inputs (Level 1) [Member] | Common Trust And Other Funds [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 2,181us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Significant Other Observable Inputs (Level 2) [Member] | Temporary Cash Investments [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Significant Other Observable Inputs (Level 2) [Member] | Registered Investment Companies [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member] | U.S. Government Securities [Member]
      
Retirement Plans [Line Items]      
Fair value of plan assets 163us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
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Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds & Debentures [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member] | Corporate Stock [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member] | Venture Capital And Buyout Partnerships [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member] | Real Estate Partnerships [Member]
      
Retirement Plans [Line Items]      
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Significant Other Observable Inputs (Level 2) [Member] | Common Trust And Other Funds [Member]
      
Retirement Plans [Line Items]      
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Significant Unobservable Inputs (Level 3) [Member]
      
Retirement Plans [Line Items]      
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Significant Unobservable Inputs (Level 3) [Member] | Temporary Cash Investments [Member]
      
Retirement Plans [Line Items]      
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[1] Other assets include accrued receivables and pending broker settlements.