NET OPERATING REVENUES (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
Hospital Operations
Disaggregation of Revenue [Line Items]
Net operating revenues	490	480
Conifer
Disaggregation of Revenue [Line Items]
Net operating revenues	332	349
Operating segments | Hospital Operations
Disaggregation of Revenue [Line Items]
Net operating revenues	3,834	3,862
Operating segments | Ambulatory Care
Disaggregation of Revenue [Line Items]
Net operating revenues	490	480
Operating segments | Conifer
Disaggregation of Revenue [Line Items]
Net operating revenues	332	349
Inter-segment eliminations
Disaggregation of Revenue [Line Items]
Net operating revenues	(136)	(146)
Continuing operations:
Disaggregation of Revenue [Line Items]
Net operating revenues	4,520	4,545
Continuing operations: | Operating segments | Hospital Operations
Disaggregation of Revenue [Line Items]
Net operating revenues	3,834	3,862
Continuing operations: | Operating segments | Hospital Operations | Other Revenues
Disaggregation of Revenue [Line Items]
Net operating revenues	294	280
Continuing operations: | Operating segments | Ambulatory Care
Disaggregation of Revenue [Line Items]
Net operating revenues	490	480
Continuing operations: | Operating segments | Conifer
Disaggregation of Revenue [Line Items]
Net operating revenues	332	349
Continuing operations: | Inter-segment eliminations
Disaggregation of Revenue [Line Items]
Net operating revenues	(136)	(146)
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Medicare
Disaggregation of Revenue [Line Items]
Net operating revenues	705	758
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Medicaid
Disaggregation of Revenue [Line Items]
Net operating revenues	281	314
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Managed care
Disaggregation of Revenue [Line Items]
Net operating revenues	2,321	2,354
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Uninsured
Disaggregation of Revenue [Line Items]
Net operating revenues	40	1
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Indemnity and other
Disaggregation of Revenue [Line Items]
Net operating revenues	193	155
Acute Care Hospitals and Related Outpatient Facilities | Continuing operations: | Operating segments | Hospital Operations | Total
Disaggregation of Revenue [Line Items]
Net operating revenues	3,540	3,582
Effect of Change in Accounting Principle
Disaggregation of Revenue [Line Items]
Net operating revenues	$ 4	$ 10