Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Condensed Consolidated Balance Sheets [Abstract]
Allowance for doubtful patient accounts	$ 3,437	$ 2,439
Current assets of hospitals held for sale	72	32
Noncurrent assets of hospitals held for sale	148	69
Current liabilities of hospitals held for sale	$ 31	$ 19
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	116,236,453	95,987,032
Common stock, shares outstanding	115,260,904	95,011,483
Treasury stock, shares	975,549	975,549