Supplemental Condensed Consolidating Financial Information and Other Collateral-Related Information - Schedule of Condensed Consolidating Statement of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income (loss)	$ 2,373	$ 1,996	$ 2,006
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in operating assets and liabilities	(3,433)	(4,272)	(3,663)
Provision for doubtful accounts	3,169	3,858	3,770
Depreciation and amortization	1,820	1,753	1,679
Income taxes	(83)	143	96
Gains on sales of facilities	(29)	10	(15)
Losses on retirement of debt	335	17
Legal claim costs	78		175
Amortization of deferred loan costs	42	55	62
Share-based compensation	163	113	56
Other	13	7	9
Net cash provided by operating activities	4,448	3,680	4,175
Cash flows from investing activities:
Purchase of property and equipment	(2,176)	(1,943)	(1,862)
Acquisition of hospitals and health care entities	(766)	(481)	(258)
Disposal of hospitals and health care entities	51	33	30
Change in investments	(37)	36	16
Other	10	9	11
Net cash used in investing activities	(2,918)	(2,346)	(2,063)
Cash flows from financing activities:
Issuance of long-term debt	5,502		4,850
Net change in revolving bank credit facilities	440	970	(685)
Repayment of long-term debt	(5,164)	(1,662)	(2,441)
Distributions to noncontrolling interests	(442)	(435)	(401)
Payment of debt issuance costs	(73)	(5)	(62)
Repurchase of common stock	(1,750)	(500)
Distributions to stockholders	(7)	(16)	(3,148)
Income tax benefits	134	113	174
Other	(18)	(90)	(67)
Net cash used in financing activities	(1,378)	(1,625)	(1,780)
Change in cash and cash equivalents	152	(291)	332
Cash and cash equivalents at beginning of period	414	705	373
Cash and cash equivalents at end of period	566	414	705
Eliminations [Member]
Cash flows from operating activities:
Net income (loss)	(1,937)	(1,875)	(1,668)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of affiliates	1,937	1,875	1,668
HCA Holdings, Inc. Issuer [Member]
Cash flows from operating activities:
Net income (loss)	1,809	1,756	1,588
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in operating assets and liabilities	(11)	(11)	57
Income taxes	(83)	143	96
Amortization of deferred loan costs	3	3	2
Share-based compensation	163	113	56
Equity in earnings of affiliates	(1,937)	(1,875)	(1,668)
Net cash provided by operating activities	(56)	129	131
Cash flows from financing activities:
Issuance of long-term debt			1,000
Payment of debt issuance costs			(12)
Repurchase of common stock	(1,750)	(500)
Distributions to stockholders	(7)	(16)	(3,148)
Income tax benefits	134	113	174
Changes in intercompany balances with affiliates, net	1,678	342	1,938
Other	1	(90)	(61)
Net cash used in financing activities	56	(151)	(109)
Change in cash and cash equivalents		(22)	22
Cash and cash equivalents at beginning of period		22
Cash and cash equivalents at end of period			22
HCA Inc. Issuer [Member]
Cash flows from operating activities:
Net income (loss)	(1,627)	(1,408)	(1,508)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in operating assets and liabilities	(12)	17	(28)
Losses on retirement of debt	335	17
Legal claim costs	78		175
Amortization of deferred loan costs	39	52	60
Other	18	9	14
Net cash provided by operating activities	(1,169)	(1,313)	(1,287)
Cash flows from financing activities:
Issuance of long-term debt	5,500		3,850
Net change in revolving bank credit facilities	440	970	(685)
Repayment of long-term debt	(5,086)	(1,254)	(2,309)
Payment of debt issuance costs	(73)	(5)	(50)
Changes in intercompany balances with affiliates, net	388	1,602	481
Net cash used in financing activities	1,169	1,313	1,287
Subsidiary Guarantors [Member]
Cash flows from operating activities:
Net income (loss)	2,681	2,299	2,428
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in operating assets and liabilities	(1,972)	(2,320)	(1,927)
Provision for doubtful accounts	1,777	2,262	2,144
Depreciation and amortization	888	855	821
Gains on sales of facilities	(25)	20	3
Other		2	(1)
Net cash provided by operating activities	3,349	3,118	3,468
Cash flows from investing activities:
Purchase of property and equipment	(1,189)	(921)	(1,039)
Acquisition of hospitals and health care entities	(34)		(110)
Disposal of hospitals and health care entities	41	17	2
Change in investments	32	(16)	(11)
Other			(2)
Net cash used in investing activities	(1,150)	(920)	(1,160)
Cash flows from financing activities:
Repayment of long-term debt	(50)	(34)	(20)
Distributions to noncontrolling interests	(65)	(71)	(60)
Changes in intercompany balances with affiliates, net	(2,109)	(2,364)	(1,960)
Net cash used in financing activities	(2,224)	(2,469)	(2,040)
Change in cash and cash equivalents	(25)	(271)	268
Cash and cash equivalents at beginning of period	112	383	115
Cash and cash equivalents at end of period	87	112	383
Subsidiary Non-Guarantors [Member]
Cash flows from operating activities:
Net income (loss)	1,447	1,224	1,166
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Change in operating assets and liabilities	(1,438)	(1,958)	(1,765)
Provision for doubtful accounts	1,392	1,596	1,626
Depreciation and amortization	932	898	858
Gains on sales of facilities	(4)	(10)	(18)
Other	(5)	(4)	(4)
Net cash provided by operating activities	2,324	1,746	1,863
Cash flows from investing activities:
Purchase of property and equipment	(987)	(1,022)	(823)
Acquisition of hospitals and health care entities	(732)	(481)	(148)
Disposal of hospitals and health care entities	10	16	28
Change in investments	(69)	52	27
Other	10	9	13
Net cash used in investing activities	(1,768)	(1,426)	(903)
Cash flows from financing activities:
Issuance of long-term debt	2
Repayment of long-term debt	(28)	(374)	(112)
Distributions to noncontrolling interests	(377)	(364)	(341)
Changes in intercompany balances with affiliates, net	43	420	(459)
Other	(19)		(6)
Net cash used in financing activities	(379)	(318)	(918)
Change in cash and cash equivalents	177	2	42
Cash and cash equivalents at beginning of period	302	300	258
Cash and cash equivalents at end of period	$ 479	$ 302	$ 300