CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Millions, except Per Share data	Jun. 30, 2011	Dec. 31, 2010
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, Authorized shares	500	500
Preferred stock, Issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, Authorized shares	5,000	5,000
Common stock, Issued shares	471	468
Common stock, Outstanding shares	454	451