v3.25.1
GOODWILL AND INTANGIBLE ASSETS (Changes in Carrying Amount of Goodwill) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2025
Dec. 31, 2024
Goodwill [Line Items]    
Balance as of January 1 $ 6,369.7  
Goodwill, Acquired During Period 36.4  
Foreign currency impact and other adjustments to Goodwill 15.0  
Balance at end of period 6,421.1  
Goodwill Impairment, Cumulative 648.5 $ 648.5
LabCorp Diagnostics [Member]    
Goodwill [Line Items]    
Balance as of January 1 5,102.5  
Goodwill, Acquired During Period 36.4  
Foreign currency impact and other adjustments to Goodwill (7.3)  
Balance at end of period 5,131.6  
Covance Drug Development [Member]    
Goodwill [Line Items]    
Balance as of January 1 1,267.2  
Goodwill, Acquired During Period 0.0  
Foreign currency impact and other adjustments to Goodwill 22.3  
Balance at end of period $ 1,289.5