Income Taxes - Schedule of Reconciliation of Federal Statutory Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation Of Statutory Federal Tax Rate [Line Items]
Federal statutory rate	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit	2.20%	2.00%	2.70%
Change in liability for uncertain tax positions		1.00%	0.30%
Nontaxable gain on acquisition of controlling interest in equity investment		(13.80%)
Tax exempt interest income	(0.20%)	(0.20%)	(0.40%)
Other items, net	(1.40%)	(1.40%)	(2.30%)
Effective income tax rate on income applicable to HCA Holdings, Inc.	35.60%	22.60%	35.30%
Income attributable to noncontrolling interests from consolidated partnerships	(4.90%)	(2.40%)	(5.80%)
Effective income tax rate on income before income taxes	30.70%	20.20%	29.50%