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, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Accounting Policies [Abstract]
Patient care costs (salaries and benefits, supplies, other operating expense and depreciation and amortization)	$ 15,638	$ 14,761	$ 31,104	$ 29,540
Cost-to-charges ratio (patient care costs as percentage of gross patient charges)	9.70%	10.10%	9.60%	10.10%
Total uncompensated care	$ 11,625	$ 10,611	$ 22,618	$ 20,613
Multiply by the cost-to-charges ratio	9.70%	10.10%	9.60%	10.10%
Estimated cost of total uncompensated care	$ 1,116	$ 1,072	$ 2,171	$ 2,082