Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS - Additional Information (Detail)

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BENEFIT PLANS - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2008
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions to retirement income plan $ 15.6 $ 14.6 $ 13.8  
Employer contribution rate to the 401(k) plan 6.00%      
Accumulated benefit obligation 710.3 646.3    
Accrued incentive compensations 66.5 61.9    
Pension Plans investment return     16.00% (20.00%)
Difference between actual returns and expected returns rate over five years period 20.00%      
Prohibited additional investing amounts The Plan is prohibited from investing additional amounts in Equifax stock once the market value of stock held by each plan exceeds 10% of the total market value of each plan.      
Minimum
        
Defined Benefit Plan Disclosure [Line Items]        
Employer contribution rate to the 401(k) plan 4.00%      
Maximum
        
Defined Benefit Plan Disclosure [Line Items]        
Employer contribution rate to the 401(k) plan 6.00%      
More than Three and within Five Years from Balance Sheet Date
        
Defined Benefit Plan Disclosure [Line Items]        
Expected return on plan assets, prior years       10.90%
More than Five and within Ten Years from Balance Sheet Date
        
Defined Benefit Plan Disclosure [Line Items]        
Expected return on plan assets, prior years       13.00%
More Than Ten Years From Balance Sheet Date
        
Defined Benefit Plan Disclosure [Line Items]        
Expected return on plan assets, prior years       7.50%
One Year from Balance Sheet Date
        
Defined Benefit Plan Disclosure [Line Items]        
Weighted-average expected rate of return 7.73%      
U.S. Retirement Income Plan, or USRIP
        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions to retirement income plan 40.0 50.0    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, projected benefit obligation 697.4 631.3    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, accumulated benefit obligation 669.1 605.6    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, fair value of plan assets 535.8 519.2    
Number of Equifax common stock shares included in plan assets   0.4    
Fair value of Equifax common stock shares included in plan assets   13.7    
Canadian Retirement Income Plan, or CRIP
        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions to retirement income plan 2.6 1.6    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, projected benefit obligation 48.7 46.7    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, accumulated benefit obligation 41.2 40.7    
Plans with projected benefit obligations and accumulated benefits benefit obligations in excess of plan's respective assets, fair value of plan assets 47.2 50.7    
Pension Benefits
        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions to retirement income plan 46.6 55.4    
Weighted-average expected rate of return 7.73% 7.73% 8.02%  
Pre-Medicare Coverage
        
Defined Benefit Plan Disclosure [Line Items]        
Initial annual rate increase in the per capita cost of of covered healthcare benefits 7.00%      
Ultimate annual rate decrease in the per capita cost of of covered healthcare benefits 5.00%      
Health care cost trend An initial 7.0% annual rate of increase in the per capita cost of covered healthcare benefits was assumed for 2012 for pre-Medicare coverage. The rate was assumed to decrease gradually to an ultimate rate of 5.0% by 2016.      
Post-Medicare Coverage
        
Defined Benefit Plan Disclosure [Line Items]        
Initial annual rate increase in the per capita cost of of covered healthcare benefits 7.00%      
Ultimate annual rate decrease in the per capita cost of of covered healthcare benefits 5.00%      
Health care cost trend An initial 7.0% annual rate of increase in the per capita cost of covered healthcare benefits was assumed for 2012 for post-Medicare coverage. The rate was assumed to decrease gradually to an ultimate rate of 5.0% by 2016.      
Trust for Benefit of Employees
        
Defined Benefit Plan Disclosure [Line Items]        
Number of shares of Equifax stock included in Employee Benefit Trusts 0.6 2.1    
Shares of Equifax stock included in Employee Benefit Trusts at cost $ 5.9 $ 41.2