SIGNIFICANT ACCOUNTING POLICIES - Net Operating Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	$ 21,070	$ 20,111	$ 17,908
Electronic Health Record Incentives
Medicare and Medicaid incentive payments for technology certification	32	72	104
Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	$ 21,070	20,111	17,908
Medicare
Medicare and Medicaid net patient revenue
Cost report filing period after end of annual cost reporting period	5 months
Increase in revenue due to adjustments for prior-year cost reports and related valuation allowances	$ 54	64	20
Medicare | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	3,374	3,403	3,395
Medicaid | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	1,346	1,451	1,482
Managed care | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	10,126	10,098	9,027
Indemnity, self-pay and other | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	1,621	1,726	1,561
Acute care hospitals - other revenue | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	21	63	53
Other operations | Continuing operations
Medicare and Medicaid net patient revenue
Net operating revenues before provision for doubtful accounts	$ 4,582	$ 3,370	$ 2,390