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		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income attributable to HCA Healthcare, Inc.	$ 1,155	$ 1,450	$ 2,428	$ 2,873
Weighted average common shares outstanding	292,527	328,171	297,459	333,119
Effect of dilutive incremental shares	3,534	4,442	4,231	4,821
Shares used for diluted earnings per share	296,061	332,613	301,690	337,940
Basic earnings per share	$ 3.95	$ 4.42	$ 8.16	$ 8.62
Diluted earnings per share	$ 3.90	$ 4.36	$ 8.05	$ 8.50