Acquisitions and Dispositions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Hospitals [Member]
Business Acquisition [Line Items]
Cash paid for acquisition		$ 58
Goodwill recorded on acquisition		53
Payment to acquire hospitals	146
Liability assumed on acquisition		33
Pretax gain on sales of business	13
Proceeds from sale of business	31
Real Estate [Member]
Business Acquisition [Line Items]
Pretax gain on sales of business		4
Proceeds from sale of business		17
Outsource Group (Member)
Business Acquisition [Line Items]
Cash paid for acquisition	278
Goodwill recorded on acquisition	180
Payment to acquire intangible assets	113
Other Healthcare Entity [Member]
Business Acquisition [Line Items]
Cash paid for acquisition	$ 39	$ 109
Number of Hospital acquired	3