Supplemental Condensed Consolidating Financial Information and Other Collateral-Related Information - Schedule of Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 718	$ 646	$ 677	$ 741
Accounts receivable, net	5,980	5,826
Inventories	1,546	1,503
Other	1,204	1,111
Total current assets	9,448	9,086
Property and equipment, net	17,329	16,352
Investments of insurance subsidiaries	368	336
Investments in and advances to affiliates	201	206
Goodwill and other intangible assets	7,357	6,704
Other	1,028	1,074
Total assets	35,731	33,758
Current liabilities:
Accounts payable	2,314	2,318
Accrued salaries	1,312	1,265
Other accrued expenses	1,783	2,035
Long-term debt due within one year	202	216
Total current liabilities	5,611	5,834
Long-term debt, net	32,751	31,160
Professional liability risks	1,179	1,148
Income taxes and other liabilities	1,256	1,249
Total liabilities	40,797	39,391
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(6,780)	(7,302)
Noncontrolling interests	1,714	1,669
Total stockholders' deficit	(5,066)	(5,633)
Total liabilities and stockholders' deficit	35,731	33,758
HCA Healthcare, Inc. Issuer [Member]
Current assets:
Cash and cash equivalents	1		1
Other	33
Total current assets	34
Investments in and advances to affiliates	28,817	27,045
Other	783	877
Total assets	29,634	27,922
Current liabilities:
Other accrued expenses	8	29
Total current liabilities	8	29
Long-term debt, net	994	993
Intercompany balances	34,983	33,784
Income taxes and other liabilities	429	418
Total liabilities	36,414	35,224
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(6,780)	(7,302)
Total stockholders' deficit	(6,780)	(7,302)
Total liabilities and stockholders' deficit	29,634	27,922
HCA Inc. Issuer [Member]
Current assets:
Other	29
Total assets	29
Current liabilities:
Other accrued expenses	279	572
Long-term debt due within one year	97	97
Total current liabilities	376	669
Long-term debt, net	31,275	29,693
Intercompany balances	(10,069)	(10,277)
Income taxes and other liabilities	2	12
Total liabilities	21,584	20,097
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(21,555)	(20,097)
Total stockholders' deficit	(21,555)	(20,097)
Total liabilities and stockholders' deficit	29
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	117	110	138	155
Accounts receivable, net	3,003	3,028
Inventories	899	890
Other	438	445
Total current assets	4,457	4,473
Property and equipment, net	8,670	8,463
Investments in and advances to affiliates	15	16
Goodwill and other intangible assets	1,728	1,728
Other	35	34
Total assets	14,905	14,714
Current liabilities:
Accounts payable	1,288	1,439
Accrued salaries	704	704
Other accrued expenses	475	464
Long-term debt due within one year	54	60
Total current liabilities	2,521	2,667
Long-term debt, net	192	199
Intercompany balances	(28,514)	(26,447)
Income taxes and other liabilities	353	387
Total liabilities	(25,448)	(23,194)
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	40,228	37,752
Noncontrolling interests	125	156
Total stockholders' deficit	40,353	37,908
Total liabilities and stockholders' deficit	14,905	14,714
Subsidiary Non-Guarantors [Member]
Current assets:
Cash and cash equivalents	600	536	$ 538	$ 586
Accounts receivable, net	2,977	2,798
Inventories	647	613
Other	733	666
Total current assets	4,957	4,613
Property and equipment, net	8,659	7,889
Investments of insurance subsidiaries	368	336
Investments in and advances to affiliates	186	190
Goodwill and other intangible assets	5,629	4,976
Other	181	163
Total assets	19,980	18,167
Current liabilities:
Accounts payable	1,026	879
Accrued salaries	608	561
Other accrued expenses	1,021	970
Long-term debt due within one year	51	59
Total current liabilities	2,706	2,469
Long-term debt, net	290	275
Intercompany balances	3,600	2,940
Professional liability risks	1,179	1,148
Income taxes and other liabilities	472	432
Total liabilities	8,247	7,264
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	10,144	9,390
Noncontrolling interests	1,589	1,513
Total stockholders' deficit	11,733	10,903
Total liabilities and stockholders' deficit	19,980	18,167
Eliminations [Member]
Current assets:
Investments in and advances to affiliates	(28,817)	(27,045)
Total assets	(28,817)	(27,045)
Current liabilities:
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(28,817)	(27,045)
Total stockholders' deficit	(28,817)	(27,045)
Total liabilities and stockholders' deficit	$ (28,817)	$ (27,045)