Acquisitions and Dispositions - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) Hospital	Dec. 31, 2020 USD ($) Hospital	Dec. 31, 2019 USD ($) Hospital
Business Acquisition [Line Items]
Proceeds from sale of business	$ 2,160	$ 68	$ 61
Real Estate and Other Investments [Member]
Business Acquisition [Line Items]
Pretax gain (loss) before tax	394
Pretax gain (loss) after tax	294
Proceeds from sale of business	$ 658
Discontinued Operations, Disposed of by Sale [Member] | Louisiana [Member]
Business Acquisition [Line Items]
Pretax gain (loss) before tax			18
Pretax gain (loss) after tax			13
Proceeds from sale of business			$ 61
Number of hospitals sold | Hospital			1
Discontinued Operations, Disposed of by Sale [Member] | Mississippi [Member]
Business Acquisition [Line Items]
Pretax gain (loss) before tax		(7)
Pretax gain (loss) after tax		(9)
Proceeds from sale of business		$ 68
Number of hospitals sold | Hospital		1
Discontinued Operations, Disposed of by Sale [Member] | Southern Georgia [Member]
Business Acquisition [Line Items]
Number of hospitals sold | Hospital	2
Discontinued Operations, Disposed of by Sale [Member] | TENNESSEE
Business Acquisition [Line Items]
Pretax gain (loss) after tax	$ 920
Discontinued Operations, Disposed of by Sale [Member] | GEORGIA, REPUBLIC OF
Business Acquisition [Line Items]
Pretax gain (loss) before tax	1,226
Proceeds from sale of business	$ 1,502
Number of hospitals sold | Hospital	5
Discontinued Operations, Disposed of by Sale [Member] | Northern Georgia [Member]
Business Acquisition [Line Items]
Number of hospitals sold | Hospital	3
Hospitals [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 67		$ 1,384
Number of hospitals purchased | Hospital	2	1	7
Hospitals [Member] | Southern Georgia [Member]
Business Acquisition [Line Items]
Number of hospitals purchased | Hospital	1
Hospitals [Member] | TENNESSEE
Business Acquisition [Line Items]
Number of hospitals purchased | Hospital	1
Nonhospital Health Care [Member]
Business Acquisition [Line Items]
Aggregate purchase price			$ 298
Other [Member]
Business Acquisition [Line Items]
Goodwill	$ 1,002	$ 279	$ 332
Hospital and other nonhospital health care entities [Member]
Business Acquisition [Line Items]
Aggregate purchase price		$ 568
Number of hospitals purchased | Hospital		1
Urgent Care Centers [Member]
Business Acquisition [Line Items]
Aggregate purchase price	594
Home Health And Hospice [Member]
Business Acquisition [Line Items]
Fair value of the noncontrolling interest in the acquiree at the acquisition date	100
Payment to acquire venture providing post acute care services	$ 330
Business acquisition percentage of voting interests acquired	80.00%
Other Nonhospital Health Care Entities [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 114
Fair value of the noncontrolling interest in the acquiree at the acquisition date	$ 117