Earnings Per Share - Schedule of Computations of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Earnings Per Share [Abstract]
Net income attributable to HCA Healthcare, Inc.	$ 1,610	$ 1,591
Weighted average common shares outstanding	246,936	264,435
Effect of dilutive incremental shares	2,504	3,581
Shares used for diluted earnings per share	249,440	268,016
Basic earnings	$ 6.52	$ 6.01
Diluted earnings	$ 6.45	$ 5.93