Supplemental Condensed Consolidating Financial Information and Other Collateral-Related Information - Schedule of Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 732	$ 646	$ 741	$ 566
Accounts receivable, net	6,501	5,826
Inventories	1,573	1,503
Other	1,171	1,111
Total current assets	9,977	9,086
Property and equipment, net	17,895	16,352
Investments of insurance subsidiaries	418	336
Investments in and advances to affiliates	199	206
Goodwill and other intangible assets	7,394	6,704	6,731	6,416
Other	710	1,074
Total assets	36,593	33,758	32,744
Current liabilities:
Accounts payable	2,606	2,318
Accrued salaries	1,369	1,265
Other accrued expenses	1,983	2,035
Long-term debt due within one year	200	216
Total current liabilities	6,158	5,834
Long-term debt, net	32,858	31,160
Professional liability risks	1,198	1,148
Income taxes and other liabilities	1,374	1,249
Total liabilities	41,588	39,391
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(6,806)	(7,302)
Noncontrolling interests	1,811	1,669
Total stockholders' deficit	(4,995)	(5,633)	(6,046)	(6,498)
Total liabilities and stockholders' deficit	36,593	33,758
HCA Healthcare, Inc. Issuer [Member]
Current assets:
Cash and cash equivalents	1
Total current assets	1
Investments in and advances to affiliates	29,581	27,045
Other	510	877
Total assets	30,092	27,922
Current liabilities:
Other accrued expenses	29	29
Total current liabilities	29	29
Long-term debt, net	995	993
Intercompany balances	35,322	33,784
Income taxes and other liabilities	552	418
Total liabilities	36,898	35,224
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(6,806)	(7,302)
Total stockholders' deficit	(6,806)	(7,302)
Total liabilities and stockholders' deficit	30,092	27,922
HCA Inc. Issuer [Member]
Current assets:
Other	50
Total assets	50
Current liabilities:
Other accrued expenses	378	572
Long-term debt due within one year	97	97
Total current liabilities	475	669
Long-term debt, net	31,367	29,693
Intercompany balances	(9,742)	(10,277)
Income taxes and other liabilities		12
Total liabilities	22,100	20,097
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(22,050)	(20,097)
Total stockholders' deficit	(22,050)	(20,097)
Total liabilities and stockholders' deficit	50
Subsidiary Guarantors [Member]
Current assets:
Cash and cash equivalents	112	113	160	89
Accounts receivable, net	3,693	3,388
Inventories	1,030	1,001
Other	663	592
Total current assets	5,498	5,094
Property and equipment, net	11,110	10,464
Investments in and advances to affiliates	22	24
Goodwill and other intangible assets	4,893	4,612
Other	47	43
Total assets	21,570	20,237
Current liabilities:
Accounts payable	1,793	1,607
Accrued salaries	862	811
Other accrued expenses	536	528
Long-term debt due within one year	64	72
Total current liabilities	3,255	3,018
Long-term debt, net	307	304
Intercompany balances	(25,228)	(22,495)
Income taxes and other liabilities	357	397
Total liabilities	(21,309)	(18,776)
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	42,755	38,857
Noncontrolling interests	124	156
Total stockholders' deficit	42,879	39,013
Total liabilities and stockholders' deficit	21,570	20,237
Subsidiary Non-Guarantors [Member]
Current assets:
Cash and cash equivalents	619	533	$ 581	$ 477
Accounts receivable, net	2,808	2,438
Inventories	543	502
Other	508	519
Total current assets	4,478	3,992
Property and equipment, net	6,785	5,888
Investments of insurance subsidiaries	418	336
Investments in and advances to affiliates	177	182
Goodwill and other intangible assets	2,501	2,092
Other	103	154
Total assets	14,462	12,644
Current liabilities:
Accounts payable	813	711
Accrued salaries	507	454
Other accrued expenses	1,040	906
Long-term debt due within one year	39	47
Total current liabilities	2,399	2,118
Long-term debt, net	189	170
Intercompany balances	(352)	(1,012)
Professional liability risks	1,198	1,148
Income taxes and other liabilities	465	422
Total liabilities	3,899	2,846
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	8,876	8,285
Noncontrolling interests	1,687	1,513
Total stockholders' deficit	10,563	9,798
Total liabilities and stockholders' deficit	14,462	12,644
Eliminations [Member]
Current assets:
Investments in and advances to affiliates	(29,581)	(27,045)
Total assets	(29,581)	(27,045)
Current liabilities:
Stockholders' (deficit) equity attributable to HCA Healthcare, Inc.	(29,581)	(27,045)
Total stockholders' deficit	(29,581)	(27,045)
Total liabilities and stockholders' deficit	$ (29,581)	$ (27,045)