NET OPERATING REVENUES - Conifer (Details) - Conifer - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Disaggregation of Revenue [Line Items]    
Net operating revenues $ 404 $ 402
Revenue cycle services | Tenet    
Disaggregation of Revenue [Line Items]    
Net operating revenues 144 147
Revenue cycle services | Non-Tenet    
Disaggregation of Revenue [Line Items]    
Net operating revenues 232 224
Other services | Tenet    
Disaggregation of Revenue [Line Items]    
Net operating revenues 6 12
Other services | Non-Tenet    
Disaggregation of Revenue [Line Items]    
Net operating revenues $ 22 $ 19
Revenue from other sources    
Disaggregation of Revenue [Line Items]    
Net operating revenues, percentage of total 7.00%