CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	1,000,000,000	1,000,000,000
Common stock, issued shares	489,379,463	489,234,401
Common stock, outstanding shares	489,379,463	489,234,401