Annual report pursuant to Section 13 and 15(d)

COST METHOD INVESTMENT (Additional Information) (Detail)

v2.4.1.9
COST METHOD INVESTMENT (Additional Information) (Detail)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Dec. 31, 2013
BRL
Dec. 31, 2012
USD ($)
Dec. 31, 2014
Boa Vista Servicos S.A.
Dec. 31, 2012
Boa Vista Servicos S.A.
BRL
Schedule of Cost-method Investments [Line Items]            
Percentage of interest in Boa Vista Servicos S.A.         15.00%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
/ us-gaap_BusinessAcquisitionAxis
= efx_BoaVistaServicosSAMember
 
Investment in Boa Vista Servicos S.A.           130us-gaap_CostMethodInvestments
/ us-gaap_BusinessAcquisitionAxis
= efx_BoaVistaServicosSAMember
Cost Method Investments, Fair Value Disclosure   38.2us-gaap_CostMethodInvestmentsFairValueDisclosure 90.0us-gaap_CostMethodInvestmentsFairValueDisclosure      
Cost-method Investments, Other than Temporary Impairment $ 0us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment $ 17.0us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment 40.0us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment $ 0us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment