CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2013 Archstone Enterprise LP
Supplemental disclosures of non-cash investing and financing activities
Obligation related to outstanding preferred interests			$ 67,500,000
Increase in redeemable noncontrolling interests associated with business acquisition			13,262,000
Value of shares of common stock issued as partial consideration for acquisition			1,875,210,000
Assumed principal amount of indebtedness			3,512,202,000
Number of shares of common stock issued as partial consideration for acquisition			14,889,706
Stock issued in connection with stock grants (in shares)	104,060	119,292
Stock issued in connection with stock grants, value	13,331,000	15,394,000
Common stock issued through the dividend reinvestment plan (in shares)	638	550
Common stock issued through the dividend reinvestment plan	78,000	76,000
Number of shares withheld to satisfy employees' tax withholding and other liabilities	33,365	29,219
Shares withheld to satisfy employees' tax withholding and other liabilities, value	3,567,000	3,590,000
Number of shares forfeited		9,226
Shares cancelled upon forfeiture		780,000
Number of options granted for common stock		215,230
Options granted for common stock, value		5,768,000
Decrease in interest expense, net		1,414,000
Common dividends declared but not paid	150,304,000	138,438,000
Decrease in other comprehensive income due to a change in other liabilities		1,414,000
Cash flow hedge losses reclassified to interest expense, net		1,391,000
(Decrease) increase in redeemable noncontrolling interests	(1,081,000)	526,000
Cash flow hedge losses reclassified to earnings	$ 1,573,000	$ 1,391,000