Annual report pursuant to Section 13 and 15(d)

ACCUMULATED OTHER COMPREHENSIVE INCOME (Changes In Accumulated Other Comprehensive Income) (Detail)

v2.4.1.9
ACCUMULATED OTHER COMPREHENSIVE INCOME (Changes In Accumulated Other Comprehensive Income) (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Balance, December 31, 2013 $ (312.6)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax $ (362.0)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Other comprehensive income before reclassifications (131.0)us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax  
Amounts reclassified from accumulated other comprehensive income 8.2us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax  
Net current-period other comprehensive income (122.8)efx_Currentsperiodothercomprehensiveincomelossnetoftax  
Balance, December 31, 2014 (435.4)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax (362.0)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Cash flow hedging transactions    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Balance, December 31, 2013 (1.9)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
 
Other comprehensive income before reclassifications 0.1us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
 
Amounts reclassified from accumulated other comprehensive income 0us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
 
Net current-period other comprehensive income 0.1efx_Currentsperiodothercomprehensiveincomelossnetoftax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
 
Balance, December 31, 2014 (1.8)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
 
Pension and other postretirement benefit plans    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Balance, December 31, 2013 (202.2)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Other comprehensive income before reclassifications (69.3)us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Amounts reclassified from accumulated other comprehensive income 8.2us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Net current-period other comprehensive income (61.1)efx_Currentsperiodothercomprehensiveincomelossnetoftax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Balance, December 31, 2014 (263.3)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= us-gaap_PensionPlansDefinedBenefitMember
 
Foreign currency    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Balance, December 31, 2013 (108.5)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ForeignCurrencyGainLossMember
 
Other comprehensive income before reclassifications (61.8)us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ForeignCurrencyGainLossMember
 
Amounts reclassified from accumulated other comprehensive income 0us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ForeignCurrencyGainLossMember
 
Net current-period other comprehensive income (61.8)efx_Currentsperiodothercomprehensiveincomelossnetoftax
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ForeignCurrencyGainLossMember
 
Balance, December 31, 2014 $ (170.3)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_ForeignCurrencyGainLossMember