Organization and Basis of Presentation - Narrative (Details) ft² in Millions, $ in Billions	Dec. 31, 2021 USD ($) ft² item property
Real Estate Properties [Line Items]
Number of Real Estate Properties \| property	64
Near-Term Development
Real Estate Properties [Line Items]
Number of Real Estate Properties \| property	11
Area of real estate property	5.3
Future Development
Real Estate Properties [Line Items]
Number of Real Estate Properties \| property	25
Area of real estate property	14.3
Commercial Real Estate
Real Estate Properties [Line Items]
Number of Real Estate Properties \| property	42
Area of real estate property	13.1
Multifamily
Real Estate Properties [Line Items]
Number of Real Estate Properties \| property	22
Number of Units in Real Estate Property \| item	8,208
Multifamily \| Asset under Construction
Real Estate Properties [Line Items]
Number of Real Estate Properties \| item	1
Number of Units in Real Estate Property \| item	808
Wholly Owned Properties \| Near-Term Development
Real Estate Properties [Line Items]
Area of real estate property	5.0
Wholly Owned Properties \| Future Development
Real Estate Properties [Line Items]
Area of real estate property	11.6
Wholly Owned Properties \| Commercial Real Estate
Real Estate Properties [Line Items]
Area of real estate property	11.3
Wholly Owned Properties \| Multifamily
Real Estate Properties [Line Items]
Number of Units in Real Estate Property \| item	6,557
Wholly Owned Properties \| Multifamily \| Asset under Construction
Real Estate Properties [Line Items]
Number of Units in Real Estate Property \| item	808
Virginia Tech
Real Estate Properties [Line Items]
Under-construction property value developed by Virginia Tech \| $	$ 1
JBG Smith, LP
Real Estate Properties [Line Items]
Ownership interest by parent	89.50%

Value of real estate property being developed by Virginia Tech.

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- Definition

Area of a real estate property.

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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- Definition

The number of real estate properties owned as of the balance sheet date.

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- Definition

The number of units in a real estate property owned as of the balance sheet date.

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- Definition

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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