Debt - Narrative (Details) - USD ($)	1 Months Ended		9 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Notes Payable, Unsecured Notes and Credit Facility
Commercial paper, maximum borrowing capacity	$ 500,000,000		$ 500,000,000
Repayments of unsecured debt			400,000,000	$ 100,000,000
Restricted cash	271,535,000		271,535,000	$ 286,127,000	$ 121,056,000
Net carrying value of apartment communities and improved land parcels securing debt	19,143,025,000		19,143,025,000		18,992,807,000
Avalon Clinton North and Avalon Clinton South
Notes Payable, Unsecured Notes and Credit Facility
Restricted cash	37,600,000		37,600,000
Asset Pledged as Collateral | Notes Payable, Other Payables
Notes Payable, Unsecured Notes and Credit Facility
Net carrying value of apartment communities and improved land parcels securing debt	1,159,639,000		1,159,639,000
Notes Payable 2.850 Maturities 2023 | Unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Repayments of unsecured debt		$ 250,000,000
Credit Facility
Notes Payable, Unsecured Notes and Credit Facility
Available borrowing capacity	$ 2,250,000,000		$ 2,250,000,000		$ 2,250,000,000
Annual facility fee, percentage			0.12%
Line of Credit Facility, Commitment Fee Percentage, Increase (Decrease)			0.005%
Credit Facility | Minimum
Notes Payable, Unsecured Notes and Credit Facility
Annual facility fee, percentage			0.095%
Credit Facility | Maximum
Notes Payable, Unsecured Notes and Credit Facility
Annual facility fee, percentage			0.295%
Credit Facility | Secured Overnight Financing Rate (SOFR)
Notes Payable, Unsecured Notes and Credit Facility
Current interest rate (as a percent)	6.12%		6.12%
Debt instrument, basis spread on variable rate (as a percent)			0.805%
Debt Instrument, Basis Spread On Variable Rate, Increase (Decrease)			0.02%
Credit Facility | Secured Overnight Financing Rate (SOFR) | Minimum
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)			0.63%
Credit Facility | Secured Overnight Financing Rate (SOFR) | Maximum
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)			1.38%
Credit Facility | SOFR Adjustment
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)			0.10%
Credit Facility | SOFR Base Rate
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)			0.705%
Variable Rate Unsecured Term Loan $150 Million | Unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Repayments of unsecured debt	$ 150,000,000