IMPAIRMENT AND RESTRUCTURING CHARGES, AND ACQUISITION-RELATED COSTS (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2015 Institution	Dec. 31, 2016 USD ($) Institution item	Dec. 31, 2015 USD ($) Institution	Dec. 31, 2015 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Institution
Impaired Long-Lived Assets Held and Used [Line Items]
Net impairment and restructuring charges and acquisition-related costs		$ 202			$ 318	$ 153
Impairment charges		54			168
Employee severance costs		35			25	16
Restructuring costs		14			6
Lease termination costs		14			19	19
Acquisition costs		52			100	95
Acquisition-related transaction costs		20			55	16
Acquisition integration charges		$ 32			45	79
Number of continuing operating segments | item		3
Impairment of property		$ 14			19	20
Number of impaired hospitals | Institution	90
Restructuring costs						$ 3
Investments impairment		19			2
Other impairment charges		$ 14
Number of hospitals with impairment charges		4	2	2		1
Aggregate carrying value of assets held and used for hospital		$ 163	$ 45	$ 45	45	$ 23
Saint Louis University Hospital
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges					$ 147
Ambulatory Care
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges		8
Hospital operations and other
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges		76
Conifer
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges		$ 3