Acquisitions and Dispositions - Additional Information (Detail) $ in Millions	9 Months Ended
Sep. 30, 2021 USD ($) Hospital	Sep. 30, 2020 USD ($)
Business Acquisitions And Dispositions [Line Items]
Proceeds from sale of business	$ 1,980	$ 68
Real Estate and Other Investments [Member]
Business Acquisitions And Dispositions [Line Items]
Pretax gain (loss) before tax	402	6
Proceeds from sale of business	$ 473	68
Number of hospitals sold \| Hospital	1
Discontinued Operations, Disposed of by Sale [Member]
Business Acquisitions And Dispositions [Line Items]
Proceeds from sale of business	$ 647
Discontinued Operations, Disposed of by Sale [Member] \| Southern Georgia [Member]
Business Acquisitions And Dispositions [Line Items]
Number of hospitals purchased \| Hospital	2
Discontinued Operations, Disposed of by Sale [Member] \| Georgia [Member]
Business Acquisitions And Dispositions [Line Items]
Pretax gain (loss) before tax	$ 655
Proceeds from sale of business	$ 860
Number of hospitals sold \| Hospital	4
Discontinued Operations, Disposed of by Sale [Member] \| Northern Georgia [Member]
Business Acquisitions And Dispositions [Line Items]
Number of hospitals sold \| Hospital	1
Hospitals [Member]
Business Acquisitions And Dispositions [Line Items]
Aggregate purchase price	$ 67
Number of hospitals purchased \| Hospital	2
Hospitals [Member] \| Southern Georgia [Member]
Business Acquisitions And Dispositions [Line Items]
Number of hospitals purchased \| Hospital	1
Hospitals [Member] \| Tennessee [Member]
Business Acquisitions And Dispositions [Line Items]
Number of hospitals purchased \| Hospital	1
Other Nonhospital Health Care Entities [Member]
Business Acquisitions And Dispositions [Line Items]
Aggregate purchase price	$ 91
Fair value of the noncontrolling interest in the acquiree at the acquisition date	111
Home Health and Hospice [Member]
Business Acquisitions And Dispositions [Line Items]
Goodwill	601
Payment to acquire venture providing post acute care services	$ 330
Business acquisition percentage of voting interests acquired	80.00%
Fair value of the noncontrolling interest in the acquiree at the acquisition date	$ 101
Hospital and other nonhospital health care entities [Member]
Business Acquisitions And Dispositions [Line Items]
Aggregate purchase price		$ 380

Business acquisitions and dispositions.

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Number of hospitals acquired.

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Number of hospitals sold.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash outflow associated with a second acquisition of a business, net of the cash acquired from the purchase.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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