CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (USD $)	1 Months Ended				3 Months Ended		9 Months Ended
	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
CONDENSED CONSOLIDATED STATEMENTS OF EQUITY
Common dividends, per share (in dollars per share)	$ 0.48	$ 0.48	$ 0.48	$ 0.48	$ 0.48	$ 0.465	$ 1.44	$ 1.395