Supplemental Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 677	$ 741	$ 588	$ 566
Accounts receivable, net	5,503	5,889
Inventories	1,503	1,439
Other	1,160	1,163
Total current assets	8,843	9,232
Property and equipment, net	15,875	15,014
Investments of insurance subsidiaries	354	432
Investments in and advances to affiliates	216	178
Goodwill and other intangible assets	6,691	6,731
Other	1,148	1,157
Total assets	33,127	32,744
Current liabilities:
Accounts payable	1,950	2,170
Accrued salaries	1,241	1,233
Other accrued expenses	1,748	1,880
Long-term debt due within one year	216	233
Total current liabilities	5,155	5,516
Long-term debt, net	31,225	30,255
Professional liability risks	1,164	1,115
Income taxes and other liabilities	1,746	1,904
Total liabilities	39,290	38,790
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(7,763)	(7,599)
Noncontrolling interests	1,600	1,553
Total stockholders' deficit	(6,163)	(6,046)
Total liabilities and stockholders' deficit	33,127	32,744
HCA Holdings, Inc. Issuer [Member]
Current assets:
Cash and cash equivalents	1
Other		223
Total current assets	1	223
Investments in and advances to affiliates	26,147	24,380
Other	962	943
Total assets	27,110	25,546
Current liabilities:
Accounts payable		2
Other accrued expenses	15	172
Total current liabilities	15	174
Long-term debt, net	993	984
Intercompany balances	33,451	31,432
Income taxes and other liabilities	414	555
Total liabilities	34,873	33,145
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(7,763)	(7,599)
Total stockholders' deficit	(7,763)	(7,599)
Total liabilities and stockholders' deficit	27,110	25,546
HCA Inc. Issuer [Member]
Current liabilities:
Other accrued expenses	294	340
Long-term debt due within one year	97	114
Total current liabilities	391	454
Long-term debt, net	29,749	28,756
Intercompany balances	(10,811)	(11,171)
Income taxes and other liabilities	551	548
Total liabilities	19,880	18,587
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(19,880)	(18,587)
Total stockholders' deficit	(19,880)	(18,587)
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	138	155	109	87
Accounts receivable, net	2,844	2,982
Inventories	905	852
Other	534	403
Total current assets	4,421	4,392
Property and equipment, net	8,681	8,328
Investments in and advances to affiliates	16	14
Goodwill and other intangible assets	1,710	1,703
Other	21	19
Total assets	14,849	14,456
Current liabilities:
Accounts payable	1,152	1,375
Accrued salaries	689	712
Other accrued expenses	541	458
Long-term debt due within one year	60	65
Total current liabilities	2,442	2,610
Long-term debt, net	200	226
Intercompany balances	(25,144)	(23,435)
Income taxes and other liabilities	362	417
Total liabilities	(22,140)	(20,182)
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	36,840	34,510
Noncontrolling interests	149	128
Total stockholders' deficit	36,989	34,638
Total liabilities and stockholders' deficit	14,849	14,456
Subsidiary Non-Guarantors [Member]
Current assets:
Cash and cash equivalents	538	586	$ 479	$ 479
Accounts receivable, net	2,659	2,907
Inventories	598	587
Other	626	537
Total current assets	4,421	4,617
Property and equipment, net	7,194	6,686
Investments of insurance subsidiaries	354	432
Investments in and advances to affiliates	200	164
Goodwill and other intangible assets	4,981	5,028
Other	165	195
Total assets	17,315	17,122
Current liabilities:
Accounts payable	798	793
Accrued salaries	552	521
Other accrued expenses	898	910
Long-term debt due within one year	59	54
Total current liabilities	2,307	2,278
Long-term debt, net	283	289
Intercompany balances	2,504	3,174
Professional liability risks	1,164	1,115
Income taxes and other liabilities	419	384
Total liabilities	6,677	7,240
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	9,187	8,457
Noncontrolling interests	1,451	1,425
Total stockholders' deficit	10,638	9,882
Total liabilities and stockholders' deficit	17,315	17,122
Eliminations [Member]
Current assets:
Investments in and advances to affiliates	(26,147)	(24,380)
Total assets	(26,147)	(24,380)
Current liabilities:
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(26,147)	(24,380)
Total stockholders' deficit	(26,147)	(24,380)
Total liabilities and stockholders' deficit	$ (26,147)	$ (24,380)