Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS (Reconciliation of Beginning and Ending Balances for Plan Assets Valued using Significant Unobservable Inputs) (Detail)

v2.4.1.9
BENEFIT PLANS (Reconciliation of Beginning and Ending Balances for Plan Assets Valued using Significant Unobservable Inputs) (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Private Equity  
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]  
Balance at December 31, 2013 $ 38.7efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Return on plan assets:  
Unrealized 0.6efx_DefinedBenefitPlanAssetsWithUnobservableInputsUnrealizedGain
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Realized 3.1efx_DefinedBenefitPlanAssetsWithUnobservableInputsRealizedGainLoss
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Purchases 9.3efx_DefinedBenefitPlanAssetsWithUnobservableInputsPurchases
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Sales (16.0)efx_DefinedBenefitPlanAssetsWithUnobservableInputsSales
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Balance at December 31, 2014 35.7efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= efx_PrivateEquitiesMember
Hedge Funds  
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]  
Balance at December 31, 2013 82.9efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Return on plan assets:  
Unrealized 2.6efx_DefinedBenefitPlanAssetsWithUnobservableInputsUnrealizedGain
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Realized 1.2efx_DefinedBenefitPlanAssetsWithUnobservableInputsRealizedGainLoss
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Purchases 0efx_DefinedBenefitPlanAssetsWithUnobservableInputsPurchases
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Sales (17.0)efx_DefinedBenefitPlanAssetsWithUnobservableInputsSales
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Balance at December 31, 2014 69.7efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
Real Assets  
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]  
Balance at December 31, 2013 12.2efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember
Return on plan assets:  
Unrealized 2.0efx_DefinedBenefitPlanAssetsWithUnobservableInputsUnrealizedGain
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember
Realized 0efx_DefinedBenefitPlanAssetsWithUnobservableInputsRealizedGainLoss
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember
Purchases 2.8efx_DefinedBenefitPlanAssetsWithUnobservableInputsPurchases
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember
Sales (0.5)efx_DefinedBenefitPlanAssetsWithUnobservableInputsSales
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember
Balance at December 31, 2014 $ 16.5efx_DefinedBenefitPlanAssetsWithUnobservableInputs
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember