Condensed Consolidated Statements Of Equity (Parenthetical) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Common dividend per share	$ 0.610	$ 0.580
6.75% Series D Preferred Shares [Member]
Preferred dividend per share	$ 13.08	$ 25.31
6.95% Series E Preferred Shares [Member]
Preferred dividend per share	$ 0.00	$ 86.88
6.5% Series F Preferred Shares [Member]
Preferred dividend per share	$ 78.99	$ 81.25