Consolidated Comprehensive Income Statements - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 2,743	$ 3,432	$ 2,696
Other comprehensive income (loss) before taxes:
Foreign currency translation	97	(224)	(63)
Unrealized gains (losses) on available-for-sale securities	1	(9)	1
Realized gains included in other operating expenses	(2)
Total unrealized gains (losses) on available-for-sale securities	(1)	(9)	1
Defined benefit plans	(43)	(35)	30
Pension costs included in salaries and benefits	18	18	32
Total defined benefit plans	(25)	(17)	62
Change in fair value of derivative financial instruments	11	20	(36)
Interest costs included in interest expense	20	109	125
Total change in fair value of derivative financial instruments	31	129	89
Other comprehensive income (loss) before taxes	102	(121)	89
Income taxes (benefits) related to other comprehensive income items	42	(48)	31
Other comprehensive income (loss)	60	(73)	58
Comprehensive income	2,803	3,359	2,754
Comprehensive income attributable to noncontrolling interests	527	542	567
Comprehensive income attributable to HCA Healthcare, Inc.	$ 2,276	$ 2,817	$ 2,187