Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
SHAREHOLDERS' EQUITY:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	163,562,149	163,562,149
Treasury stock, shares	27,777,625	15,197,680