BASIS OF PRESENTATION - Investments in Unconsolidated Affiliates (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) Institution
Schedule of Equity Method Investments [Line Items]
Net operating revenues | $	$ 610	$ 1,803
Net income | $	129	364
Net income attributable to the investee | $	$ 83	$ 241
Number of outpatient centers		470
Number of hospitals recorded using equity method		129
Number of outpatient centers recorded not using equity method		216
Ambulatory Care
Schedule of Equity Method Investments [Line Items]
Number of outpatient centers		330
Number of outpatient centers recorded using equity method		114
Number of outpatient centers recorded not using equity method		212
Hospital operations and other
Schedule of Equity Method Investments [Line Items]
Number of hospitals recorded using equity method		4
Number of outpatient centers recorded not using equity method		4