Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) $ in Millions		3 Months Ended			9 Months Ended
	Oct. 08, 2020 USD ($)	Sep. 30, 2020 USD ($) Hospital State Surgery_Center	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Hospital State Surgery_Center	Sep. 30, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of owned and operated hospitals | Hospital		187			187
Number of freestanding surgery centers | Surgery_Center		121			121
Number of facilities locations | State		21			21
General and administrative expense		$ 117		$ 88	$ 289	$ 268
Performance obligations for inpatient/ outpatient services satisfied period					Our performance obligations for outpatient services are generally satisfied over a period of less than one day.
Charity care amount		3,160		3,425	$ 9,972	9,641
Estimated costs of charity care		376		$ 421	1,207	1,167
Government stimulus income reversal		(822)			0
CARES Act Provider Relief Fund [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred social security taxes		441			441
Employee retention payroll tax credits					60
Accelerated Medicare payments received	$ 4,400				4,449
General and targeted distributions recived	$ 1,600				1,674
Government stimulus income reversal		$ 822	$ (822)
Out of Network Services [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenues					$ 55	$ 86
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of income of federal poverty level eligible for charity care					400.00%