NET OPERATING REVENUES - Conifer (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Net operating revenues	$ 4,520	$ 4,545
Conifer
Disaggregation of Revenue [Line Items]
Net operating revenues	332	349
Conifer | Revenue cycle services | Tenet
Disaggregation of Revenue [Line Items]
Net operating revenues	134	142
Conifer | Revenue cycle services | Non-Tenet
Disaggregation of Revenue [Line Items]
Net operating revenues	176	180
Conifer | Other services | Tenet
Disaggregation of Revenue [Line Items]
Net operating revenues	2	4
Conifer | Other services | Non-Tenet
Disaggregation of Revenue [Line Items]
Net operating revenues	$ 20	$ 23
Conifer | Revenue from other sources
Disaggregation of Revenue [Line Items]
Net operating revenues, percentage of total	7.00%