Supplemental Condensed Consolidating Financial Information and Other Collateral-Related Information - Schedule of Quarterly Consolidated Financial Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Items Net Interest And Other Financial Income [Line Items]
Revenues	$ 8,434	$ 8,062	$ 8,112	$ 8,405	$ 7,769	$ 7,258	$ 7,249	$ 7,406	$ 33,013	$ 29,682	$ 28,035
Net income	427	455	485	639	2,042	146	320	334	2,006	2,842	1,573
Net income attributable to HCA Holdings, Inc.	$ 314	$ 360	$ 391	$ 540	$ 1,935	$ 61	$ 229	$ 240	$ 1,605	$ 2,465	$ 1,207
Basic earnings per share	$ 0.71	$ 0.82	$ 0.89	$ 1.23	$ 4.43	$ 0.12	$ 0.44	$ 0.54	$ 3.65	$ 5.17	$ 2.83
Diluted earnings per share	$ 0.68	$ 0.78	$ 0.85	$ 1.18	$ 4.25	$ 0.11	$ 0.43	$ 0.52	$ 3.49	$ 4.97	$ 2.76