Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($) Hospital State Surgery_Center	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($) $ / shares	Sep. 30, 2015 USD ($) $ / shares Hospital State Surgery_Center	Sep. 30, 2014 USD ($)
Accounting Policies [Abstract]
Number of owned and operated hospitals | Hospital	168			168
Number of freestanding surgery centers | Surgery_Center	114			114
Number of facilities locations | State	20			20
General and administrative expense	$ 79	$ 71		$ 237	$ 206
Adjustments to Medicare revenues			$ 142	$ 142
Adjustment to increase Medicaid revenues in diluted per share | $ / shares			$ 0.20	$ 0.20