| Quarterly Financial Data (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified | 3 Months Ended | 12 Months Ended | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dec. 31, 2011 | Sep. 30, 2011 | Jun. 30, 2011 | Mar. 31, 2011 | Dec. 31, 2010 | Sep. 30, 2010 | Jun. 30, 2010 | Mar. 31, 2010 | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | |||||||||||
| Quarterly Financial Information [Line Items] | |||||||||||||||||||||
| Operating revenue | $ 509.7 | $ 490.4 | $ 487.1 | $ 472.6 | $ 482.0 | $ 473.8 | $ 460.7 | $ 443.0 | $ 1,959.8 | $ 1,859.5 | $ 1,716.0 | ||||||||||
| Operating income | 125.7 | 121.6 | 114.6 | 109.1 | 109.7 | 110.2 | 105.8 | 104.3 | 471.0 | 430.0 | 381.8 | ||||||||||
| Consolidated income from continuing operations | 74.5 | 69.3 | 37.1 | 59.3 | 64.0 | 63.6 | 59.8 | 55.9 | 240.2 | 243.3 | 224.4 | ||||||||||
| Discontinued operations, net of tax | 1.5 | 15.2 | 13.6 | 2.7 | 1.5 | 31.5 | 16.1 | ||||||||||||||
| Consolidated net income | 76.0 | 69.3 | 37.1 | 59.3 | 64.0 | 78.8 | 73.4 | 58.6 | 241.7 | 274.8 | 240.5 | ||||||||||
| Net income attributable to Equifax | $ 74.4 | $ 66.7 | $ 34.5 | $ 57.3 | $ 62.2 | $ 76.5 | $ 71.3 | $ 56.7 | $ 232.9 | $ 266.7 | $ 233.9 | ||||||||||
| Basic earnings per common share | |||||||||||||||||||||
| Net income from continuing operations attributable to Equifax | $ 0.61 | $ 0.55 | $ 0.28 | $ 0.47 | $ 0.51 | $ 0.50 | $ 0.46 | $ 0.43 | $ 1.90 | $ 1.89 | $ 1.72 | ||||||||||
| Discontinued operations attributable to Equifax | $ 0.01 | $ 0.12 | $ 0.11 | $ 0.02 | $ 0.01 | $ 0.25 | $ 0.13 | ||||||||||||||
| Net income attributable to Equifax | $ 0.62 | [1] | $ 0.55 | [1] | $ 0.28 | [1] | $ 0.47 | [1] | $ 0.51 | [1] | $ 0.62 | [1] | $ 0.57 | [1] | $ 0.45 | [1] | $ 1.91 | $ 2.14 | $ 1.85 | ||
| Diluted earnings per common share | |||||||||||||||||||||
| Net income from continuing operations attributable to Equifax | $ 0.60 | $ 0.54 | $ 0.28 | $ 0.46 | $ 0.50 | $ 0.49 | $ 0.45 | $ 0.42 | $ 1.87 | $ 1.86 | $ 1.70 | ||||||||||
| Discontinued operations attributable to Equifax | $ 0.01 | $ 0.12 | $ 0.11 | $ 0.02 | $ 0.01 | $ 0.25 | $ 0.13 | ||||||||||||||
| Net income attributable to Equifax | $ 0.61 | [1] | $ 0.54 | [1] | $ 0.28 | [1] | $ 0.46 | [1] | $ 0.50 | [1] | $ 0.61 | [1] | $ 0.56 | [1] | $ 0.44 | [1] | $ 1.88 | $ 2.11 | $ 1.83 | ||
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- Definition The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of net income (loss) derived from continuing operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items before deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of net income (loss) derived from discontinued operations during the period, net of related tax effect, per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The amount of net income or loss derived from discontinued operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available. 
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- Definition The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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