Dispositions and Acquisitions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Significant Acquisitions and Disposals [Line Items]
Payment to acquired real properties	$ 1	$ 11
Peak Behavioral Health Services
Significant Acquisitions and Disposals [Line Items]
Aggregate cash proceeds from divestiture of businesses	34
Number of acute care hospital beds included in sale	104
Hospital San Juan Capestrano
Significant Acquisitions and Disposals [Line Items]
Aggregate cash proceeds from divestiture of businesses		$ 53
Number of acute care hospital beds included in sale		108