Accounting Policies - Schedule of Revenues from Third Party Payers, Uninsured and Other Payers (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Revenues From Third Party Payers [Line Items]
Revenues	$ 75,600	$ 70,603	$ 64,968
Revenues ratio from third party payers	100.00%	100.00%	100.00%
Medicare [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 11,273	$ 10,780	$ 10,585
Revenues from third party payers, Ratio	15.30%	14.90%	16.30%
Managed Medicare [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 13,435	$ 11,987	$ 10,496
Revenues from third party payers, Ratio	17.00%	17.80%	16.20%
Medicaid [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 5,909	$ 4,678	$ 3,606
Revenues from third party payers, Ratio	6.60%	7.80%	5.60%
Managed Medicaid [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 3,693	$ 3,980	$ 3,879
Revenues from third party payers, Ratio	5.60%	4.90%	6.00%
Managed Care and Other Insurers [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 36,968	$ 34,954	$ 31,819
Revenues from third party payers, Ratio	49.50%	48.90%	49.00%
International (Managed Care and Other Insurers) [Member]
Revenues From Third Party Payers [Line Items]
Revenues from third party payers	$ 1,864	$ 1,682	$ 1,509
Revenues from third party payers, Ratio	2.40%	2.50%	2.30%
Other [Member]
Revenues From Third Party Payers [Line Items]
Revenues	$ 2,458	$ 2,542	$ 3,074
Other, Ratio	3.60%	3.20%	4.60%