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Stock Option and Incentive Plan Stock and Units - LTIP Issuances (Details) - LTIP Units [Member] - Boston Properties Limited Partnership - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued		406,646	451,044	430,824
Value Of LTIP Units Issued		$ 26.9	$ 26.8	$ 29.9
Weighted average price (per unit)		$ 66.10	$ 59.41	$ 69.29
Expected life assumed to calculate per unit fair value per LTIP unit (in years)	[1]	5 years 8 months 12 days	5 years 8 months 12 days	5 years 8 months 12 days
Risk-free rate	[1]	4.45%	4.03%	3.67%
Expected price volatility	[1]	38.00%	36.00%	32.00%
[1] LTIP Units were valued using a Monte Carlo simulation method model in accordance with the provisions of ASC 718.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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