Equity (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Changes in equity
Balance at the beginning of the period			$ 4,401,892,000
Net income attributable to common stockholders			214,667,000
Unrealized loss (gain) on cash flow hedges	(27,798,000)	(19,336,000)	(16,789,000)	(19,420,000)
Change in redemption value of redeemable noncontrolling interest			(521,000)	(1,218,000)
Noncontrolling interests			(3,477,000)
Dividends declared to common stockholders			(186,170,000)
Issuance of common stock, net of withholdings			160,213,000
Amortization of deferred compensation			12,425,000
Balance at the end of the period	4,582,240,000		4,582,240,000
Common stock
Changes in equity
Balance at the beginning of the period			952,000
Issuance of common stock, net of withholdings			14,000
Balance at the end of the period	966,000		966,000
Additional paid-in capital
Changes in equity
Balance at the beginning of the period			4,652,457,000
Issuance of common stock, net of withholdings			162,448,000
Amortization of deferred compensation			12,425,000
Balance at the end of the period	4,827,330,000		4,827,330,000
Accumulated earnings less dividends
Changes in equity
Balance at the beginning of the period			(171,648,000)
Net income attributable to common stockholders			214,667,000
Change in redemption value of redeemable noncontrolling interest			(521,000)
Dividends declared to common stockholders			(186,170,000)
Issuance of common stock, net of withholdings			(2,249,000)
Balance at the end of the period	(145,921,000)		(145,921,000)
Accumulated other comprehensive loss
Changes in equity
Balance at the beginning of the period			(87,020,000)
Unrealized loss (gain) on cash flow hedges			(16,789,000)
Balance at the end of the period	(103,809,000)		(103,809,000)
Total AvalonBay stockholders' equity
Changes in equity
Balance at the beginning of the period			4,394,741,000
Net income attributable to common stockholders			214,667,000
Unrealized loss (gain) on cash flow hedges			(16,789,000)
Change in redemption value of redeemable noncontrolling interest			(521,000)
Dividends declared to common stockholders			(186,170,000)
Issuance of common stock, net of withholdings			160,213,000
Amortization of deferred compensation			12,425,000
Balance at the end of the period	4,578,566,000		4,578,566,000
Noncontrolling interests
Changes in equity
Balance at the beginning of the period			7,151,000
Noncontrolling interests			(3,477,000)
Balance at the end of the period	$ 3,674,000		$ 3,674,000