IMPAIRMENT AND RESTRUCTURING CHARGES, AND ACQUISITION-RELATED COSTS (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) hospital
Impaired Long-Lived Assets Held and Used [Line Items]
Number of continuing operating segments | segment	3
Impairment and restructuring charges, and acquisition-related costs	$ 290	$ 185	$ 209
Impairment charges	92	42	77
Restructuring charges	184	137	115
Acquisition costs	14	6	17
Impairment charges	76	26	40
Aggregate carrying value of assets held and used of the hospitals for which impairment charges were recorded			130
Other impairment charges		16	4
Employee severance costs	65	57	68
Lease termination costs	14	6	17
Restructuring costs	32	46	30
Acquisition-related transaction costs		6	$ 10
Number of hospitals with impairment charges | hospital			2
Acquisition integration charges			$ 7
Chicago-area
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges			24
Aspen
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges			9
Hospital Operations
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges	79	31	67
Ambulatory Care
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges	12	6	9
Conifer
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges	1	5	1
Series of Individual Business Acquisitions
Impaired Long-Lived Assets Held and Used [Line Items]
Acquisition-related transaction costs	14	6	$ 10
Global Business Center in Republic of Philippines
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring charges	50	$ 28
USPI Management Equity Plan
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring charges	23
Building
Impaired Long-Lived Assets Held and Used [Line Items]
Aggregate carrying value of assets held and used of the hospitals for which impairment charges were recorded	483
Other impairment charges	$ 16