Acquisitions and Dispositions - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) Hospital	Dec. 31, 2023 USD ($) Hospital	Dec. 31, 2022 USD ($)
Business Acquisition [Line Items]
Pretax gain (loss) before tax		$ (5)
Proceeds from sale of business	$ 328	193	$ 1,237
Real Estate and Other Investments [Member]
Business Acquisition [Line Items]
Pretax gain (loss) before tax	(5)		274
Gain (loss) after tax	$ (4)		$ 200
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property		Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property
Proceeds from sale of business	$ 33	31	$ 326
Discontinued Operations, Disposed of by Sale [Member]
Business Acquisition [Line Items]
Pretax gain (loss) before tax			1,027
Gain (loss) after tax			$ 527
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]			Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property
Proceeds from sale of business			$ 911
Hospital Facility [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 112	$ 229
Number of hospitals purchased | Hospital	3	4
Proceeds from sale of business	$ 295	$ 162
Number of hospitals sold | Hospital	1	2
Hospital Facility One [Member] | Discontinued Operations, Disposed of by Sale [Member] | CALIFORNIA
Business Acquisition [Line Items]
Pretax gain (loss) before tax	$ 189
Gain (loss) after tax	$ 145
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property
Hospital Facility Two [Member] | Discontinued Operations, Disposed of by Sale [Member] | CALIFORNIA
Business Acquisition [Line Items]
Pretax gain (loss) before tax	$ (170)
Gain (loss) after tax	$ (130)
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property
Nonhospital Health Care [Member]
Business Acquisition [Line Items]
Aggregate purchase price	$ 154	$ 406	224
Fair value of the noncontrolling interest in the acquiree at the acquisition date			72
Other [Member]
Business Acquisition [Line Items]
Goodwill	$ 170	$ 362	$ 262