The percentage of debt instruments tendered.

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The value of debt instruments tendered.

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Represents the debt price as a percentage of the principal amount at which the debt instrument is issued.

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Secured debt including debt on real estate held for sale.

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The amount of tender offer consideration per each $1,000 principal amount.

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Unsecured short-term debt instrument issued by corporations which are highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Gross amount of debt extinguished.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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The effective interest rate at the end of the reporting period.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term unsecured obligations issued by corporations and other borrowers to investors (with maturities initially due after one year or beyond the operating cycle if longer).

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Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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DEBT, NET (UNITED DOMINION REALTY, L.P.) - Additional Information (Details)	1 Months Ended		3 Months Ended	9 Months Ended
	Jul. 31, 2020 USD ($)	Feb. 29, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Oct. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)
Fixed and variable rate debt
Long-term commercial paper			$ 500,000,000.0	$ 500,000,000.0
Borrowings outstanding			2,900,000	2,900,000		$ 2,900,000
Extinguishment of debt costs				35,495,000	$ 6,283,000
Commercial Paper
Fixed and variable rate debt
Commercial paper program			$ 230,000,000	$ 230,000,000		$ 300,000,000
Interest rate at the end of the period			0.30%	0.30%		2.00%
Credit facilities \| Fixed Rate Debt
Fixed and variable rate debt
Principal outstanding						$ 204,590,000
Repayment of debt			$ 201,900,000
Extinguishment of debt costs			9,000,000.0	$ 9,000,000.0
Mortgages Note Payable
Fixed and variable rate debt
Repayment of debt			43,900,000
Mortgages Note Payable \| Fixed Rate Debt
Fixed and variable rate debt
Principal outstanding			892,291,000	892,291,000		884,869,000
Extinguishment of debt costs			2,200,000	2,200,000
Tax-exempt secured notes payable \| Variable Rate Debt
Fixed and variable rate debt
Principal outstanding			27,000,000	27,000,000		27,000,000
Term Loan due September 2023
Fixed and variable rate debt
Senior Notes			35,000,000	35,000,000		35,000,000
Term Loan due September 2023 \| Fixed Rate Debt
Fixed and variable rate debt
Senior Notes			315,000,000	315,000,000		315,000,000
3.75% Medium-Term Notes Due July 2024
Fixed and variable rate debt
Senior Notes			182,867,000	182,867,000		299,530,000
Extinguishment of debt costs			12,800,000	12,800,000
2.10% Medium Term Note Due August 1, 2032
Fixed and variable rate debt
Interest rate	2.10%
Senior Notes			399,583,000	399,583,000
Debt	$ 400,000,000.0
Price as percentage of principal amount	99.894
4.64% Secured Debt Due in 2023
Fixed and variable rate debt
Interest rate	4.64%
Repayment of debt	$ 245,800,000
4.00% Medium-Term Note due October 2025
Fixed and variable rate debt
Senior Notes			299,656,000	299,656,000		299,604,000
2.95% Medium-Term Note due September 2026
Fixed and variable rate debt
Senior Notes			300,000,000	300,000,000		300,000,000
3.50 Medium-Term Note due July 2027
Fixed and variable rate debt
Senior Notes			299,524,000	299,524,000		299,471,000
3.50% Medium-Term Notes Due January 2028
Fixed and variable rate debt
Senior Notes			299,135,000	299,135,000		299,046,000
3.20% Medium-Term Notes due January 2030
Fixed and variable rate debt
Interest rate		3.20%					3.20%	3.20%
Senior Notes		$ 600,000,000.0	612,756,000	612,756,000		402,281,000
Debt		$ 200,000,000.0					$ 100,000,000.0	$ 300,000,000.0
Price as percentage of principal amount		105.660
Medium-Term Notes Due August 2031
Fixed and variable rate debt
Debt			150,000,000.0	150,000,000.0
United Dominion Realty L.P. \| Financial Guarantee
Fixed and variable rate debt
Guarantor borrowing capacity			1,100,000,000	1,100,000,000
United Dominion Realty L.P. \| Unsecured Commercial Bank Credit Facility
Fixed and variable rate debt
Long-term commercial paper			500,000,000	500,000,000
United Dominion Realty L.P. \| Mortgages Note Payable
Fixed and variable rate debt
Principal outstanding			$ 72,500,000	$ 72,500,000
Interest rate			3.10%	3.10%
United Dominion Realty L.P. \| Mortgages Note Payable \| Fixed Rate Debt
Fixed and variable rate debt
Principal outstanding			$ 72,500,000	$ 72,500,000		72,500,000
United Dominion Realty L.P. \| Mortgages Note Payable \| Variable Rate Debt \| Operating Partnership
Fixed and variable rate debt
Principal outstanding			$ 27,000,000.0	$ 27,000,000.0
Interest rate at the end of the period			0.77%	0.77%
United Dominion Realty L.P. \| Tax-exempt secured notes payable \| Variable Rate Debt
Fixed and variable rate debt
Principal outstanding			$ 27,000,000	$ 27,000,000		27,000,000
United Dominion Realty L.P. \| Unsecured Commercial Paper
Fixed and variable rate debt
Borrowings outstanding			230,000,000.0	230,000,000.0		$ 300,000,000.0
United Dominion Realty L.P. \| Term Loan due September 2023
Fixed and variable rate debt
Guarantor borrowing capacity			350,000,000	350,000,000
United Dominion Realty L.P. \| 3.75% Medium-Term Notes Due July 2024
Fixed and variable rate debt
Guarantor borrowing capacity			183,000,000	183,000,000
United Dominion Realty L.P. \| 2.10% Medium Term Note Due August 1, 2032
Fixed and variable rate debt
Guarantor borrowing capacity			400,000,000	400,000,000
United Dominion Realty L.P. \| 4.00% Medium-Term Note due October 2025
Fixed and variable rate debt
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Realty L.P. \| 2.95% Medium-Term Note due September 2026
Fixed and variable rate debt
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Realty L.P. \| 3.50 Medium-Term Note due July 2027
Fixed and variable rate debt
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Realty L.P. \| 3.50% Medium-Term Notes Due January 2028
Fixed and variable rate debt
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Realty L.P. \| Medium-Term note due January 2029
Fixed and variable rate debt
Guarantor borrowing capacity			300,000,000	300,000,000
United Dominion Realty L.P. \| 3.20% Medium-Term Notes due January 2030
Fixed and variable rate debt
Guarantor borrowing capacity			600,000,000	600,000,000
United Dominion Realty L.P. \| Medium-Term Notes Due August 2031
Fixed and variable rate debt
Guarantor borrowing capacity			400,000,000	400,000,000
United Dominion Realty L.P. \| 3.10% senior unsecured notes due 2034
Fixed and variable rate debt
Guarantor borrowing capacity			$ 300,000,000	$ 300,000,000
Cash Tender Offer \| 3.75% Medium-Term Notes Due July 2024
Fixed and variable rate debt
Principal outstanding	$ 300,000,000.0
Interest rate	3.75%
Tendered value	$ 116,900,000
Tendered percentage	39.00%
Tender offer consideration per each $1,000	$ 1,101.92