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Equity, Capital and Other Interests Text (Details) (USD $) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2013 | Jun. 30, 2014
Additional Common Shares Authorized |  | 13,000,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased |  | 13,000,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased |  | 12,968,760
Stock Repurchased And Retired |  | (31,240)
Treasury Stock Acquired, Average Cost Per Share |  | $ 56.87
Value Of Stock Repurchased And Retired |  | $ 1,800,000
OP Units repurchased and retired |  | 31,240
Number of Units in Real Estate Property |  | 111,491
Payments to Acquire Interest in Subsidiaries and Affiliates |  | 5,500,000
Increase To Reduction Of Paid In Capital |  | 2,300,000
Reduction In Partially Owned Properties |  | 2,200,000
Reduction In Other Liabilities |  | 1,000,000
Archstone Transaction [Member] |  |
Issuance of Common Shares | 34,468,085 |
Stock Issued During Period, Value, New Issues | $ 1,900,000,000 |
Average Price Per Common Share Issued | $ 55.99 |
Units Issued During Period New Issues |  | 34,468,085
Enclave at Wellington [Domain] |  |
Number of Units in Real Estate Property |  | 268

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