v2.4.0.6
CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (USD $)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
CONSOLIDATED STATEMENTS OF EQUITY      
Dividends to common stockholders, per share (in dollars per share) $ 2.30 $ 2.14 $ 2.05