Basis of Presentation and Significant Accounting Policies - Schedule of Estimated Cost of Uncompensated Care (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accounting Policies [Abstract]
Patient care costs (salaries and benefits, supplies, other operating expenses and depreciation and amortization)	$ 13,157	$ 12,744
Cost-to-charges ratio (patient care costs as percentage of gross patient charges)	10.40%	11.30%
Total uncompensated care	$ 7,991	$ 7,005
Multiply by the cost-to-charges ratio	10.40%	11.30%
Estimated cost of total uncompensated care	$ 831	$ 792