Earnings Per Share - Schedule of Computations of Basic and Diluted Earnings Per Share (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income attributable to HCA Holdings, Inc.	$ 365	$ 360	$ 1,132	$ 1,291
Weighted average common shares outstanding	447,329	440,899	446,125	439,441
Effect of dilutive incremental shares	16,240	18,616	16,926	19,381
Shares used for diluted earnings per share	463,569	459,515	463,051	458,822
Basic earnings per share	$ 0.82	$ 0.82	$ 2.54	$ 2.94
Diluted earnings per share	$ 0.79	$ 0.78	$ 2.44	$ 2.81