Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) Endoscopy_Center Surgery_Center State Hospital	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Endoscopy_Center Surgery_Center State Hospital	Sep. 30, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of owned and operated hospitals | Hospital	183		183
Number of freestanding surgery centers | Surgery_Center	123		123
Number of freestanding endoscopy centers | Endoscopy_Center	21		21
Number of facilities locations | State	20		20
General and administrative expense	$ 87	$ 117	$ 301	$ 289
Performance obligations for inpatient/ outpatient services satisfied period			Our performance obligations for inpatient services are generally satisfied over periodsthat average approximately five days, and revenues are recognized based on charges incurred in relation to total expected charges. Our performance obligations for outpatient services are generally satisfied over a period of less than one day.
Charity care amount	3,509	3,160	$ 10,135	9,972
Estimated costs of charity care	$ 413	$ 376	1,155	1,207
Out of Network Services [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenues			$ 33	$ 55
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of income of federal poverty level eligible for charity care			400.00%