Debt - Narrative (Details)		1 Months Ended		3 Months Ended		9 Months Ended
	Feb. 28, 2019 USD ($)	Sep. 30, 2022 USD ($) extensionOption	Feb. 28, 2022 USD ($)	Sep. 30, 2022 USD ($) extensionOption	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) extensionOption	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Notes Payable, Unsecured Notes and Credit Facility
Repayments of unsecured debt						$ 100,000,000	$ 462,147,000
Commercial paper, maximum borrowing capacity		$ 500,000,000		$ 500,000,000		500,000,000
Commercial paper		49,985,000		49,985,000		49,985,000		$ 0
Loss on debt extinguishment				1,646,000	$ 17,890,000	1,646,000	$ 17,768,000
Credit Facility		0		0		0		0
Net carrying value of apartment communities and improved land parcels securing debt		18,948,643,000		18,948,643,000		18,948,643,000		18,709,584,000
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		1,189,325,000		$ 1,189,325,000		$ 1,189,325,000
Variable Rate Unsecured Term Loan $100 Million | Fixed rate unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Repayments of unsecured debt			$ 100,000,000
Notes Payable Maturities 2047
Notes Payable, Unsecured Notes and Credit Facility
Loss on debt extinguishment		$ 1,399,000
Notes Payable Maturities 2047 | Fixed rate unsecured notes
Notes Payable, Unsecured Notes and Credit Facility
Fixed interest rate		4.15%		4.15%		4.15%
Notes Payable Maturities 2047 | Secured Debt
Notes Payable, Unsecured Notes and Credit Facility
Repayments of secured debt		$ 35,276,000
Fixed interest rate		6.16%		6.16%		6.16%
Line of Credit
Notes Payable, Unsecured Notes and Credit Facility
Available borrowing capacity	$ 1,750,000,000	$ 2,250,000,000		$ 2,250,000,000		$ 2,250,000,000
Number of extension options | extensionOption		2		2		2
Extension option period		6 months
Extension fee		$ 1,406,000
Capitalization rate	6.00%	5.75%
Accordion feature, higher borrowing capacity option		$ 3,000,000,000		$ 3,000,000,000		$ 3,000,000,000
Annual facility fee, percentage	0.125%					0.125%
Percent of credit facility available to competitive bid option		65.00%		65.00%		65.00%
Credit Facility		$ 0		$ 0		$ 0		0
Outstanding balance of letters of credit		6,914,000		6,914,000		6,914,000		11,969,000
Amount available under commercial paper program and letters of credit		$ 2,193,101,000		$ 2,193,101,000		$ 2,193,101,000
Line of Credit | Minimum
Notes Payable, Unsecured Notes and Credit Facility
Annual facility fee, percentage						0.10%
Line of Credit | Maximum
Notes Payable, Unsecured Notes and Credit Facility
Annual facility fee, percentage						0.30%
Line of Credit | Secured Overnight Financing Rate (SOFR)
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)						0.825%
Current interest rate (as a percent)		3.81%		3.81%		3.81%
Line of Credit | Secured Overnight Financing Rate (SOFR) | Minimum
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)						0.65%
Line of Credit | Secured Overnight Financing Rate (SOFR) | Maximum
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)						1.40%
Line of Credit | SOFR Adjustment
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)						0.10%
Line of Credit | SOFR Base Rate
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)						0.725%
Line of Credit | LIBOR
Notes Payable, Unsecured Notes and Credit Facility
Debt instrument, basis spread on variable rate (as a percent)	0.775%
Other Letter of Credit
Notes Payable, Unsecured Notes and Credit Facility
Outstanding balance of letters of credit		$ 45,182,000		$ 45,182,000		$ 45,182,000		$ 39,581,000
Fixed Rate Mortgage Notes Payable
Notes Payable, Unsecured Notes and Credit Facility
Weighted average interest rate, debt (as a percent)		3.40%		3.40%		3.40%		3.70%
Variable Rate Mortgage Notes Payable Unsecured Term Loan and Credit Facility
Notes Payable, Unsecured Notes and Credit Facility
Weighted average interest rate, debt (as a percent)		4.10%		4.10%		4.10%		1.70%