Supplemental Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 852	$ 741	$ 586	$ 566
Accounts receivable, net	5,880	5,889
Inventories	1,415	1,439
Other	1,054	1,163
Total current assets	9,201	9,232
Property and equipment, net	15,057	15,014
Investments of insurance subsidiaries	425	432	432
Investments in and advances to affiliates	174	178
Goodwill and other intangible assets	6,713	6,731
Other	1,206	1,157
Total assets	32,776	32,744
Current liabilities:
Accounts payable	1,944	2,170
Accrued salaries	1,309	1,233
Other accrued expenses	1,919	1,880
Long-term debt due within one year	226	233
Total current liabilities	5,398	5,516
Long-term debt, net	30,328	30,255
Professional liability risks	1,116	1,115
Income taxes and other liabilities	1,933	1,904
Total liabilities	38,775	38,790
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(7,556)	(7,599)
Noncontrolling interests	1,557	1,553
Total stockholders' deficit	(5,999)	(6,046)
Total liabilities and stockholders' deficit	32,776	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	24,980	24,380
Other	973	943
Total assets	25,954	25,546
Current liabilities:
Accounts payable	1	2
Other accrued expenses	303	172
Total current liabilities	304	174
Long-term debt, net	992	984
Intercompany balances	31,677	31,432
Income taxes and other liabilities	537	555
Total liabilities	33,510	33,145
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(7,556)	(7,599)
Total stockholders' deficit	(7,556)	(7,599)
Total liabilities and stockholders' deficit	25,954	25,546
HCA Inc. Issuer [Member]
Current liabilities:
Other accrued expenses	271	340
Long-term debt due within one year	109	114
Total current liabilities	380	454
Long-term debt, net	28,833	28,756
Intercompany balances	(10,764)	(11,171)
Income taxes and other liabilities	568	548
Total liabilities	19,017	18,587
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(19,017)	(18,587)
Total stockholders' deficit	(19,017)	(18,587)
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	221	155	111	87
Accounts receivable, net	3,041	2,982
Inventories	834	852
Other	454	403
Total current assets	4,550	4,392
Property and equipment, net	8,267	8,328
Investments in and advances to affiliates	18	14
Goodwill and other intangible assets	1,702	1,703
Other	19	19
Total assets	14,556	14,456
Current liabilities:
Accounts payable	1,199	1,375
Accrued salaries	729	712
Other accrued expenses	450	458
Long-term debt due within one year	62	65
Total current liabilities	2,440	2,610
Long-term debt, net	212	226
Intercompany balances	(23,936)	(23,435)
Income taxes and other liabilities	426	417
Total liabilities	(20,858)	(20,182)
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	35,280	34,510
Noncontrolling interests	134	128
Total stockholders' deficit	35,414	34,638
Total liabilities and stockholders' deficit	14,556	14,456
Subsidiary Non-Guarantors [Member]
Current assets:
Cash and cash equivalents	630	586	$ 475	$ 479
Accounts receivable, net	2,839	2,907
Inventories	581	587
Other	600	537
Total current assets	4,650	4,617
Property and equipment, net	6,790	6,686
Investments of insurance subsidiaries	425	432
Investments in and advances to affiliates	156	164
Goodwill and other intangible assets	5,011	5,028
Other	214	195
Total assets	17,246	17,122
Current liabilities:
Accounts payable	744	793
Accrued salaries	580	521
Other accrued expenses	895	910
Long-term debt due within one year	55	54
Total current liabilities	2,274	2,278
Long-term debt, net	291	289
Intercompany balances	3,023	3,174
Professional liability risks	1,116	1,115
Income taxes and other liabilities	402	384
Total liabilities	7,106	7,240
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	8,717	8,457
Noncontrolling interests	1,423	1,425
Total stockholders' deficit	10,140	9,882
Total liabilities and stockholders' deficit	17,246	17,122
Eliminations [Member]
Current assets:
Investments in and advances to affiliates	(24,980)	(24,380)
Total assets	(24,980)	(24,380)
Current liabilities:
Stockholders' (deficit) equity attributable to HCA Holdings, Inc.	(24,980)	(24,380)
Total stockholders' deficit	(24,980)	(24,380)
Total liabilities and stockholders' deficit	$ (24,980)	$ (24,380)