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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to HCA Holdings, Inc.	$ 483	$ 423	$ 830	$ 767
Weighted average common shares outstanding	438,833	446,612	440,482	445,513
Effect of dilutive incremental shares	14,176	16,572	14,738	17,269
Shares used for diluted earnings per share	453,009	463,184	455,220	462,782
Basic earnings per share	$ 1.10	$ 0.95	$ 1.88	$ 1.72
Diluted earnings per share	$ 1.07	$ 0.91	$ 1.82	$ 1.66