Consolidated Comprehensive Income Statements (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 2,373	$ 1,996	$ 2,006
Other comprehensive income (loss) before taxes:
Foreign currency translation	(74)	18	37
Unrealized gains (losses) on available-for-sale securities	9	(7)	6
Defined benefit plans	(158)	134	(89)
Pension costs included in salaries and benefits	21	38	46
Total defined benefit plans	(137)	172	(43)
Change in fair value of derivative financial instruments	(36)	3	(151)
Interest costs included in interest expense	132	131	122
Total change in fair value of derivative financial instruments	96	134	(29)
Other comprehensive income (loss) before taxes	(106)	317	(29)
Income taxes (benefits) related to other comprehensive income items	(40)	117	(12)
Other comprehensive income (loss)	(66)	200	(17)
Comprehensive income	2,307	2,196	1,989
Comprehensive income attributable to noncontrolling interests	498	440	401
Comprehensive income attributable to HCA Holdings, Inc.	$ 1,809	$ 1,756	$ 1,588