Unsecured Debt - Narrative (Details)	1 Months Ended					3 Months Ended	12 Months Ended
	Jul. 31, 2025 USD ($)	May 31, 2025 USD ($) extensionOption	May 31, 2024 USD ($)	Oct. 31, 2022 USD ($) extensionOption	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2025 USD ($) property lineOfCredit	Jul. 01, 2025 USD ($)	Jun. 30, 2025 USD ($)	Apr. 30, 2025 USD ($)	Feb. 28, 2025 USD ($)	Dec. 31, 2024 USD ($)	Aug. 31, 2024 USD ($)	Jul. 01, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Aug. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Oct. 31, 2019 USD ($)	Aug. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)	Feb. 28, 2019 USD ($)	Mar. 31, 2018 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Mar. 31, 2015 USD ($)	Apr. 30, 2014 USD ($)
Debt Instrument [Line Items]
Debt instrument face amount							$ 600,000,000.0
Unsecured debt, net							$ 6,015,921,000					$ 5,473,788,000
Number of lines of credit | lineOfCredit							2
Commercial Paper
Debt Instrument [Line Items]
Debt instrument, term		397 days
Maximum amount authorized		$ 750,000,000.0
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 1,500,000,000	$ 1,200,000,000					$ 75,000,000.0	$ 35,000,000.0
CPPIB Interest
Debt Instrument [Line Items]
Investment interest acquired						45.00%
Essex Portfolio, L.P.
Debt Instrument [Line Items]
Unsecured debt, net							$ 6,015,921,000					5,473,788,000
Interest Rate Swap
Debt Instrument [Line Items]
Debt instrument face amount							$ 600,000,000.0			$ 300,000,000.0							$ 300,000,000.0
Derivative hedged item		$ 197,500,000
Fixed interest rate		4.10%					4.10%
Bonds public offering - fixed rate, net
Debt Instrument [Line Items]
Unamortized debt issuance expense							$ 549,900,000					549,800,000
Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Aggregate principal amount										$ 500,000,000.0
Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							5,450,000,000					5,200,000,000
Debt instrument, repaid, principal			$ 400,000,000.0
Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																				$ 600,000,000.0
Line of Credit
Debt Instrument [Line Items]
Lines of credit and commercial paper							0					137,945,000
Line of Credit | Line of Credit Working Capital
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 75,000,000.0
Unsecured Line of Credit
Debt Instrument [Line Items]
Basis spread on rate							0.775%
Number of extension options | property							2
Number of extension options (in extensions)							6 months
Unsecured Line of Credit | Line of Credit Working Capital
Debt Instrument [Line Items]
Lines of credit and commercial paper							$ 0					62,900,000
Unsecured Debt
Debt Instrument [Line Items]
Total debt							6,050,000,000
Unamortized debt issuance expense							30,400,000					26,300,000
Unsecured debt, net							6,015,921,000					5,473,788,000
Unamortized discount (premium), net							3,600,000					100,000
Unsecured Debt | Variable Rate Term Loan
Debt Instrument [Line Items]
Debt instrument face amount				$ 300,000,000.0
Basis spread on rate				0.85%
Number of extension options | extensionOption				3
Term extension period				12 months
Coupon rate				4.20%
Unsecured Debt | Bonds public offering - fixed rate, net
Debt Instrument [Line Items]
Unsecured debt, net							5,419,253,000					5,175,217,000
Unsecured Term Loan 0.850%, Due May 2028
Debt Instrument [Line Items]
Number of extension options | extensionOption		2
Number of extension options (in extensions)		1 year
Unsecured Term Loan 0.850%, Due May 2028 | Unsecured Debt
Debt Instrument [Line Items]
Debt instrument face amount		$ 300,000,000.0
Coupon rate		0.85%
Total debt							300,000,000.0
Unsecured Term Loan 0.850%, Due May 2028 | Unsecured Debt | Maximum
Debt Instrument [Line Items]
Debt instrument face amount		$ 600,000,000.0
Unsecured Bonds 4.875% | Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount							$ 350,000,000.0
Coupon rate							4.875%
Debt instrument, debt offering price, percentage of principal							99.093%
Unamortized debt issuance expense							$ 344,000,000.0					0
Unsecured Bonds 4.875% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 350,000,000					0
Coupon rate							4.875%
Unsecured Bonds 3.375% | Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount							$ 450,000,000.0
Coupon rate							3.375%
Unsecured Bonds 3.375% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 450,000,000					450,000,000																$ 450,000,000.0
Coupon rate							3.375%																					3.375%
Debt offering price																												99.386%
Unsecured debt, net							$ 449,800,000					449,100,000
Unsecured Bonds 5.375% | Bonds public offering - fixed rate, net
Debt Instrument [Line Items]
Unamortized debt issuance expense							395,000,000.0					0
Unsecured Bonds 5.375% | Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount											$ 400,000,000.0
Coupon rate											5.375%
Debt instrument, debt offering price, percentage of principal											99.604%
Unsecured Bonds 5.375% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 400,000,000					0
Coupon rate							5.375%
Unsecured Bonds 5.500% | Bonds public offering - fixed rate, net | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																$ 350,000,000.0
Coupon rate																5.50%
Debt instrument, debt offering price, percentage of principal																99.752%
Unsecured Bonds 5.500% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 550,000,000					550,000,000	$ 200,000,000.0
Coupon rate							5.50%
Debt instrument, debt offering price, percentage of principal amount													102.871%
Debt instrument, debt offering price, effective yield percentage													5.11%
Unsecured Bonds 2.550% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 300,000,000					300,000,000
Coupon rate							2.55%
Unsecured debt, net							$ 297,600,000					297,100,000
Unsecured Bonds 2.550% | Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																		$ 300,000,000.0
Coupon rate																		2.55%
Debt offering price																		99.367%
Unsecured Bonds 3.375% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount																		$ 300,000,000.0
Coupon rate																		3.375%
Unsecured Bonds 1.700% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 450,000,000					450,000,000
Coupon rate							1.70%
Unsecured debt, net							$ 448,200,000					447,200,000
Unsecured Bonds 1.700% | Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																			$ 450,000,000.0
Coupon rate																			1.70%
Debt offering price																			99.423%
Unsecured Bonds 2.650% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount					$ 150,000,000.0		$ 650,000,000					650,000,000
Coupon rate							2.65%
Debt offering price					105.66%
Unsecured debt, net							$ 650,500,000					650,600,000
Reoffer yield percentage					2.093%
Unsecured Bonds 2.650% | Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																					$ 500,000,000.0
Coupon rate																					2.65%
Debt offering price																					99.628%
Repayments of secured debt						$ 100,300,000
Unsecured Bonds 1.650% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 300,000,000					300,000,000
Coupon rate							1.65%
Debt offering price																				99.035%
Unsecured Bonds 1.650% | Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																				$ 300,000,000.0
Coupon rate																				1.65%
Unsecured debt, net							$ 297,200,000					296,700,000
Unsecured Bonds 2.650% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 300,000,000					300,000,000
Coupon rate							2.65%
Debt offering price																				99.691%
Unsecured Bonds 2.650% | Senior Notes | Essex Portfolio, L.P.
Debt Instrument [Line Items]
Debt instrument face amount																				$ 300,000,000.0
Coupon rate																				2.65%
Unsecured debt, net							$ 296,300,000					296,100,000
Unsecured Bonds 3.625% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount																				$ 300,000,000.0
Coupon rate																				3.625%
Unsecured Bonds 3.000% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 550,000,000					550,000,000										$ 150,000,000.0	$ 400,000,000.0
Coupon rate							3.00%																3.00%
Debt offering price																						101.685%	98.632%
Unsecured debt, net							$ 547,000,000.0					546,200,000
Unsecured Bonds 4.000% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 500,000,000					500,000,000												$ 150,000,000.0	$ 350,000,000.0
Coupon rate							4.00%																		4.00%
Debt offering price																								100.717%	99.188%
Unsecured debt, net							$ 498,000,000.0					497,300,000
Unsecured Bonds 4.500% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 300,000,000					300,000,000														$ 300,000,000.0
Coupon rate							4.50%																			4.50%
Debt offering price																										99.591%
Unsecured debt, net							$ 296,500,000					296,400,000
Unsecured Bonds 3.625% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount							$ 350,000,000					350,000,000															$ 350,000,000.0
Coupon rate							3.625%																				3.625%
Debt offering price																											99.423%
Unsecured debt, net							$ 349,300,000					348,800,000
Senior Unsecured Notes Maturing April 1, 2025 | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount																													$ 500,000,000.0
Coupon rate																													3.50%
Debt offering price																													99.747%
Unsecured debt, net												499,900,000
Unsecured Bonds 3.875% | Senior Notes
Debt Instrument [Line Items]
Debt instrument face amount																														$ 400,000,000.0
Coupon rate																														3.875%
Debt offering price																														99.234%
Unsecured debt, net							0					0
New Credit Facility | Unsecured Debt | Line of Credit
Debt Instrument [Line Items]
Debt instrument face amount							1,580,000,000
Unamortized debt issuance expense							7,300,000					6,200,000
Line of credit facility increase amount	$ 1,000,000,000.0
Option to increase	$ 2,500,000,000
Unsecured Line of Credit | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,500,000,000					1,500,000,000
Lines of credit and commercial paper							0					$ 75,000,000.0
Commerical Paper Program | Commercial Paper
Debt Instrument [Line Items]
Unamortized debt issuance expense							$ 400,000