Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	$ 4,430,110,000		$ 4,449,734,000
Mezzanine notes payable	310,735,000		311,040,000
Unsecured senior notes	5,836,290,000		5,835,854,000
Unsecured exchangeable senior notes	0		744,880,000
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	4,430,110,000		4,449,734,000
Mezzanine notes payable	310,735,000		311,040,000
Unsecured senior notes	5,836,290,000		5,835,854,000
Unsecured exchangeable senior notes	0	[1]	744,880,000	[1]
Total	10,577,135,000		11,341,508,000
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable	4,577,435,000		4,545,283,000
Mezzanine notes payable	310,764,000		311,064,000
Unsecured senior notes	6,145,060,000		6,050,517,000
Unsecured exchangeable senior notes	0		750,266,000
Total	11,033,259,000		11,657,130,000
ASC 470-20 Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Impact of accounting pronouncement			$ 2,400,000

[1] Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.