CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, Authorized shares	500	500
Preferred stock, Issued shares
Preferred stock, outstanding shares
Common stock, par value	$ 0.01	$ 0.01
Common stock, Authorized shares	5,000	5,000
Common stock, Issued shares	476	473
Common stock, Outstanding shares	452	455