BASIS OF PRESENTATION (Details)	9 Months Ended
Sep. 30, 2018 center
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of outpatient centers	475

Represents the number of provider-based outpatient centers operated by subsidiaries.

No definition available.

Name:	thc_NumberOfProviderBasedOutPatientCentersOperatedBySubsidiaries
Namespace Prefix:	thc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration