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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income attributable to HCA Healthcare, Inc.	$ 1,134	$ 2,269	$ 3,562	$ 5,142
Weighted average common shares outstanding	285,958	318,072	293,583	328,048
Effect of dilutive incremental shares	3,894	5,957	4,119	5,200
Shares used for diluted earnings per share	289,852	324,029	297,702	333,248
Basic earnings per share	$ 3.97	$ 7.13	$ 12.13	$ 15.67
Diluted earnings per share	$ 3.91	$ 7.00	$ 11.97	$ 15.43