Quarterly report pursuant to Section 13 or 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
3 Months Ended
Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]  
Balance, December 31, 2014 $ (435.4)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Other comprehensive income before reclassifications (36.9)us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
Amounts reclassified from accumulated other comprehensive income 2.5us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
Net current-period other comprehensive income (34.4)efx_CurrentsPeriodOtherComprehensiveIncomeLossNetOfTax
Balance, March 31, 2015 (469.8)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
Foreign currency  
Accumulated Other Comprehensive Income (Loss) [Line Items]  
Balance, December 31, 2014 (170.3)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= efx_AccumulatedtranslationadjustmentmemberMember
Other comprehensive income before reclassifications (37.1)us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= efx_AccumulatedtranslationadjustmentmemberMember
Amounts reclassified from accumulated other comprehensive income 0us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= efx_AccumulatedtranslationadjustmentmemberMember
Net current-period other comprehensive income (37.1)efx_CurrentsPeriodOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= efx_AccumulatedtranslationadjustmentmemberMember
Balance, March 31, 2015 (207.4)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= efx_AccumulatedtranslationadjustmentmemberMember
Pension and other postretirement benefit plans  
Accumulated Other Comprehensive Income (Loss) [Line Items]  
Balance, December 31, 2014 (263.3)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Other comprehensive income before reclassifications 0us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Amounts reclassified from accumulated other comprehensive income 2.5us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Net current-period other comprehensive income 2.5efx_CurrentsPeriodOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Balance, March 31, 2015 (260.8)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember
Cash flow hedging transactions  
Accumulated Other Comprehensive Income (Loss) [Line Items]  
Balance, December 31, 2014 (1.8)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
Other comprehensive income before reclassifications 0.2us-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 0.2efx_CurrentsPeriodOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember
Balance, March 31, 2015 $ (1.6)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember