Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017 USD ($) State Hospital Surgery_Center	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) State Hospital Surgery_Center	Sep. 30, 2016 USD ($)
Accounting Policies [Abstract]
Number of owned and operated hospitals \| Hospital	177		177
Number of freestanding surgery centers \| Surgery_Center	119		119
Number of facilities locations \| State	20		20
General and administrative expense \| $	$ 91	$ 94	$ 273	$ 272

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration