Income Per Share (Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	22,000,089	20,888,386	21,546,210
Weighted Average Of Operating Partnership Common Units Not Owned By Us [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	2,521,400	4,143,713	4,647,629
Potentially Dilutive 2029 Debentures [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	6,649,510	6,486,358	6,328,234
Series C Cumulative Convertible Preferred Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities		814,063	3,016,780
Series D Cumulative Convertible Preferred Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	470,748	4,016,560	6,242,257
Series E Cumulative Convertible Preferred Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	5,176,886	4,122,752	1,311,310
Series F Cumulative Convertible Preferred Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	3,283,169	1,304,940
Series G Cumulative Convertible Preferred Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities	3,898,376