| ACQUISITIONS AND INVESTMENTS - Narrative (Details) - USD ($) $ in Millions | Oct. 01, 2021 | Feb. 10, 2021 | Sep. 30, 2021 | Mar. 31, 2021 | Feb. 29, 2020 | Apr. 30, 2019 | 
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| Kount | ||||||
| Business Acquisition [Line Items] | ||||||
| Business acquisition, voting interests acquired (as a percent) | 100.00% | |||||
| Cash consideration paid for business combination | $ 640 | |||||
| Hiretech and i2Verify | ||||||
| Business Acquisition [Line Items] | ||||||
| Business acquisition, voting interests acquired (as a percent) | 100.00% | |||||
| Health e(fx) and Teletrack | ||||||
| Business Acquisition [Line Items] | ||||||
| Business acquisition, voting interests acquired (as a percent) | 100.00% | |||||
| Appriss Insights | ||||||
| Business Acquisition [Line Items] | ||||||
| Business acquisition, voting interests acquired (as a percent) | 100.00% | |||||
| Cash consideration paid for business combination | $ 1,825 | |||||
| India Joint Venture | ||||||
| Business Acquisition [Line Items] | ||||||
| Additional remaining interest acquired (as a percent) | 40.60% | |||||
| PayNet | ||||||
| Business Acquisition [Line Items] | ||||||
| Business acquisition, voting interests acquired (as a percent) | 100.00% | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Percentage of voting equity interests acquired in a business combination achieved in stages, including equity interests in the acquiree held by the acquirer immediately before the acquisition date and acquired at the acquisition date. No definition available. 
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