Supplemental Condensed Consolidating Financial Information and Other Collateral-Related Information - Schedule of Condensed Consolidating Comprehensive Income Statement (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Statement of Income Captions [Line Items]
Revenues	$ 13,523	$ 12,694	$ 12,602	$ 12,517	$ 12,274	$ 11,451	$ 11,529	$ 11,423	$ 51,336	$ 46,677	$ 43,614
Salaries and benefits									23,560	21,425	20,059
Supplies									8,481	7,724	7,316
Other operating expenses									9,481	8,608	8,051
Equity in earnings of affiliates									(43)	(29)	(45)
Depreciation and amortization									2,596	2,278	2,131
Interest expense (income)									1,824	1,755	1,690
Losses (gains) on sales of facilities									(18)	(428)	(8)
Losses on retirement of debt									211	9	39
Total expenses including equity in earnings of affiliates									46,092	41,342	39,233
Income (loss) before income taxes									5,244	5,335	4,381
Provision (benefit) for income taxes									1,099	946	1,638
Net income (loss)	1,273	764	927	1,181	1,245	896	966	1,282	4,145	4,389	2,743
Net income attributable to noncontrolling interests									640	602	527
Net income (loss) attributable to HCA Healthcare, Inc.	$ 1,071	$ 612	$ 783	$ 1,039	$ 1,064	$ 759	$ 820	$ 1,144	3,505	3,787	2,216
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									3,426	3,779	2,276
HCA Healthcare, Inc. Issuer [Member]
Condensed Statement of Income Captions [Line Items]
Other operating expenses									7	8	6
Equity in earnings of affiliates									(3,597)	(3,688)	(2,476)
Interest expense (income)									64	64	64
Total expenses including equity in earnings of affiliates									(3,526)	(3,616)	(2,406)
Income (loss) before income taxes									3,526	3,616	2,406
Provision (benefit) for income taxes									21	(171)	190
Net income (loss)									3,505	3,787	2,216
Net income (loss) attributable to HCA Healthcare, Inc.									3,505	3,787	2,216
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									3,426	3,779	2,276
HCA Inc. Issuer [Member]
Condensed Statement of Income Captions [Line Items]
Interest expense (income)									4,025	3,580	3,088
Losses on retirement of debt									211	9	39
Total expenses including equity in earnings of affiliates									4,236	3,589	3,127
Income (loss) before income taxes									(4,236)	(3,589)	(3,127)
Provision (benefit) for income taxes									(976)	(834)	(1,154)
Net income (loss)									(3,260)	(2,755)	(1,973)
Net income (loss) attributable to HCA Healthcare, Inc.									(3,260)	(2,755)	(1,973)
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									(3,311)	(2,745)	(1,953)
Subsidiary Guarantors [Member]
Condensed Statement of Income Captions [Line Items]
Revenues									29,220	27,482	25,774
Salaries and benefits									12,898	12,287	11,619
Supplies									4,802	4,560	4,286
Other operating expenses									4,643	4,463	4,249
Equity in earnings of affiliates									(6)	(7)	(6)
Depreciation and amortization									1,447	1,335	1,237
Interest expense (income)									(2,001)	(1,635)	(1,309)
Losses (gains) on sales of facilities									(14)	(357)	(2)
Management fees									(768)	(639)	(621)
Total expenses including equity in earnings of affiliates									21,001	20,007	19,453
Income (loss) before income taxes									8,219	7,475	6,321
Provision (benefit) for income taxes									1,874	1,714	2,293
Net income (loss)									6,345	5,761	4,028
Net income attributable to noncontrolling interests									91	99	108
Net income (loss) attributable to HCA Healthcare, Inc.									6,254	5,662	3,920
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									6,215	5,712	3,898
Subsidiary Non-Guarantors [Member]
Condensed Statement of Income Captions [Line Items]
Revenues									22,116	19,195	17,840
Salaries and benefits									10,662	9,138	8,440
Supplies									3,679	3,164	3,030
Other operating expenses									4,831	4,137	3,796
Equity in earnings of affiliates									(37)	(22)	(39)
Depreciation and amortization									1,149	943	894
Interest expense (income)									(264)	(254)	(153)
Losses (gains) on sales of facilities									(4)	(71)	(6)
Management fees									768	639	621
Total expenses including equity in earnings of affiliates									20,784	17,674	16,583
Income (loss) before income taxes									1,332	1,521	1,257
Provision (benefit) for income taxes									180	237	309
Net income (loss)									1,152	1,284	948
Net income attributable to noncontrolling interests									549	503	419
Net income (loss) attributable to HCA Healthcare, Inc.									603	781	529
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									614	713	591
Eliminations [Member]
Condensed Statement of Income Captions [Line Items]
Equity in earnings of affiliates									3,597	3,688	2,476
Total expenses including equity in earnings of affiliates									3,597	3,688	2,476
Income (loss) before income taxes									(3,597)	(3,688)	(2,476)
Net income (loss)									(3,597)	(3,688)	(2,476)
Net income (loss) attributable to HCA Healthcare, Inc.									(3,597)	(3,688)	(2,476)
Comprehensive income (loss) attributable to HCA Healthcare, Inc.									$ (3,518)	$ (3,680)	$ (2,536)