Supplemental Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Comprehensive Income Statement (Detail) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
	Dec. 09, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2014	Dec. 31, 2012	Sep. 30, 2016	Sep. 30, 2015
Supplemental Condensed Consolidating Financial Information [Line Items]
Revenues before provision for doubtful accounts		$ 11,110	$ 11,014			$ 33,241	$ 32,268
Provision for doubtful accounts		840	1,158			2,392	2,839
Revenues		10,270	9,856			30,849	29,429
Salaries and benefits		4,740	4,619			14,133	13,509
Supplies		1,699	1,644			5,131	4,952
Other operating expenses		1,897	1,796			5,627	5,268
Electronic health record incentive income		(1)	(9)			(10)	(46)
Equity in earnings of affiliates		(22)	(9)			(44)	(38)
Depreciation and amortization		495	482			1,463	1,424
Interest expense		432	411			1,275	1,255
Gains on sales of facilities		(3)	2			(8)	(2)
Losses on retirement of debt		4				4	125
Legal claim costs	$ 434	11	77	$ 78	$ 175	33	77
Total expenses including equity in earnings of affiliates		9,252	9,013			27,604	26,524
Income (loss) before income taxes		1,018	843			3,245	2,905
Provision (benefit) for income taxes		273	270			898	947
Net income (loss)		745	573			2,347	1,958
Net income attributable to noncontrolling interests		127	124			377	411
Net income (loss) attributable to HCA Holdings, Inc.		618	449			1,970	1,547
Comprehensive income (loss) attributable to HCA Holdings, Inc.		621	430			1,894	1,561
HCA Holdings, Inc. Issuer [Member]
Supplemental Condensed Consolidating Financial Information [Line Items]
Other operating expenses		1	7			5	9
Equity in earnings of affiliates		(573)	(464)			(1,843)	(1,690)
Interest expense		16	16			48	100
Losses on retirement of debt							122
Total expenses including equity in earnings of affiliates		(556)	(441)			(1,790)	(1,459)
Income (loss) before income taxes		556	441			1,790	1,459
Provision (benefit) for income taxes		(62)	(8)			(180)	(88)
Net income (loss)		618	449			1,970	1,547
Net income (loss) attributable to HCA Holdings, Inc.		618	449			1,970	1,547
Comprehensive income (loss) attributable to HCA Holdings, Inc.		621	430			1,894	1,561
HCA Inc. Issuer [Member]
Supplemental Condensed Consolidating Financial Information [Line Items]
Interest expense		711	608			2,031	1,807
Losses on retirement of debt		4				4	3
Legal claim costs		11	77			33	77
Total expenses including equity in earnings of affiliates		726	685			2,068	1,887
Income (loss) before income taxes		(726)	(685)			(2,068)	(1,887)
Provision (benefit) for income taxes		(268)	(258)			(763)	(716)
Net income (loss)		(458)	(427)			(1,305)	(1,171)
Net income (loss) attributable to HCA Holdings, Inc.		(458)	(427)			(1,305)	(1,171)
Comprehensive income (loss) attributable to HCA Holdings, Inc.		(432)	(418)			(1,288)	(1,142)
Subsidiary Guarantors [Member]
Supplemental Condensed Consolidating Financial Information [Line Items]
Revenues before provision for doubtful accounts		5,591	5,721			16,957	16,519
Provision for doubtful accounts		391	689			1,383	1,535
Revenues		5,200	5,032			15,574	14,984
Salaries and benefits		2,373	2,357			7,074	6,824
Supplies		888	853			2,672	2,576
Other operating expenses		905	865			2,660	2,523
Electronic health record incentive income		(1)	(6)			(6)	(31)
Equity in earnings of affiliates		(1)	(1)			(4)	(4)
Depreciation and amortization		242	230			707	683
Interest expense		(235)	(156)			(646)	(498)
Gains on sales of facilities			(1)				(5)
Management fees		(206)	(178)			(601)	(534)
Total expenses including equity in earnings of affiliates		3,965	3,963			11,856	11,534
Income (loss) before income taxes		1,235	1,069			3,718	3,450
Provision (benefit) for income taxes		447	394			1,347	1,284
Net income (loss)		788	675			2,371	2,166
Net income attributable to noncontrolling interests		24	21			67	68
Net income (loss) attributable to HCA Holdings, Inc.		764	654			2,304	2,098
Comprehensive income (loss) attributable to HCA Holdings, Inc.		766	657			2,312	2,109
Subsidiary Non-Guarantors [Member]
Supplemental Condensed Consolidating Financial Information [Line Items]
Revenues before provision for doubtful accounts		5,519	5,293			16,284	15,749
Provision for doubtful accounts		449	469			1,009	1,304
Revenues		5,070	4,824			15,275	14,445
Salaries and benefits		2,367	2,262			7,059	6,685
Supplies		811	791			2,459	2,376
Other operating expenses		991	924			2,962	2,736
Electronic health record incentive income			(3)			(4)	(15)
Equity in earnings of affiliates		(21)	(8)			(40)	(34)
Depreciation and amortization		253	252			756	741
Interest expense		(60)	(57)			(158)	(154)
Gains on sales of facilities		(3)	3			(8)	3
Management fees		206	178			601	534
Total expenses including equity in earnings of affiliates		4,544	4,342			13,627	12,872
Income (loss) before income taxes		526	482			1,648	1,573
Provision (benefit) for income taxes		156	142			494	467
Net income (loss)		370	340			1,154	1,106
Net income attributable to noncontrolling interests		103	103			310	343
Net income (loss) attributable to HCA Holdings, Inc.		267	237			844	763
Comprehensive income (loss) attributable to HCA Holdings, Inc.		242	206			743	737
Eliminations [Member]
Supplemental Condensed Consolidating Financial Information [Line Items]
Equity in earnings of affiliates		573	464			1,843	1,690
Total expenses including equity in earnings of affiliates		573	464			1,843	1,690
Income (loss) before income taxes		(573)	(464)			(1,843)	(1,690)
Net income (loss)		(573)	(464)			(1,843)	(1,690)
Net income (loss) attributable to HCA Holdings, Inc.		(573)	(464)			(1,843)	(1,690)
Comprehensive income (loss) attributable to HCA Holdings, Inc.		$ (576)	$ (445)			$ (1,767)	$ (1,704)