Basis of Presentation and Significant Accounting Policies - Schedule of Estimated Cost of Uncompensated Care (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accounting Policies [Abstract]
Patient care costs (salaries and benefits, supplies, other operating expense and depreciation and amortization)	$ 14,761	$ 13,561	$ 29,540	$ 26,718
Cost-to-charges ratio (patient care costs as percentage of gross patient charges)	10.10%	10.50%	10.10%	10.50%
Total uncompensated care	$ 10,611	$ 8,483	$ 20,613	$ 16,474
Multiply by the cost-to-charges ratio	10.10%	10.50%	10.10%	10.50%
Estimated cost of total uncompensated care	$ 1,072	$ 899	$ 2,082	$ 1,730