Boston Properties LTD Partnership 10-Q 9 May 14 2014 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2014	5-May-14
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Entity Registrant Name	'BOSTON PROPERTIES LTD PARTNERSHIP	'
Amendment Flag	'false	'
Entity Central Index Key	'0001043121	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	0

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Real estate, at cost	$16,828,341	$16,727,886
Construction in progress	1,564,821	1,523,179
Land held for future development	300,498	297,376
Less: accumulated depreciation	-3,196,522	-3,096,910
Total real estate	15,497,138	15,451,531
Cash and cash equivalents	1,179,573	2,365,137
Cash held in escrows	54,240	57,201
Investments in securities	18,026	16,641
Tenant and other receivables (net of allowance for doubtful accounts of $1,625 and $1,636, respectively	37,812	59,464
Accrued rental income (net of allowance of $3,448 and $3,636, respectively)	661,730	651,603
Deferred charges, net	861,567	884,450
Prepaid expenses and other assets	178,488	184,477
Investments in unconsolidated joint ventures	127,356	126,084
Total assets	18,615,930	19,796,588
Liabilities:	'	'
Mortgage notes payable	4,430,110	4,449,734
Unsecured senior notes (net of discount of $13,710 and $14,146 respectively	5,836,290	5,835,854
Unsecured exchangeable senior notes (net of discount of $0 and $182, respectively)	0	744,880
Unsecured line of credit	0	0
Mezzanine notes payable	310,735	311,040
Outside member's notes payable	180,000	180,000
Accounts payable and accrued expenses	218,028	202,470
Distributions payable	114,799	497,242
Accrued interest payable	178,651	167,523
Other liabilities	556,772	578,969
Total liabilities	11,825,385	12,967,712
Commitments and contingencies	0	0
Noncontrolling interests:	'	'
Redeemable interest in property partnerships	100,327	99,609
Redeemable partnership units-666,116 series two preferred units outstanding (874,168 common units at redemption value, if converted) at March 31, 2014 and December 31, 2013	100,118	87,740
Redeemable partnership units - 360,126 series four preferred units outstanding at redemption value at March 31, 2014 and December 31, 2013	18,006	18,006
Redeemable partnership units-15,583,853 and 15,583,370 common units and 1,554,353 and 1,455,761 long term incentive units outstanding at redemption value at March 31, 2014 and December 31, 2013, respectively	1,962,839	1,710,218
Capital:	'	'
5.25% Series B cumulative redeemable preferred units, liquidation preference of $2,500 per unit, 80,000 units issued and outstanding at March 31, 2014 and December 31,2013	193,623	193,623
Boston Properties Limited Partnership partners' capital-1,701,555 and 1,700,222 general partner units and 151,315,756 and 151,282,879 limited partner units outstanding at March 31, 2014 and December 31, 2013,	3,690,539	3,993,548
Noncontrolling interests in property partnerships	725,093	726,132
Total capital	4,609,255	4,913,303
Total liabilities and capital	$18,615,930	$19,796,588

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Tenant and other receivables, allowance for doubtful accounts	$1,625	$1,636
Accrued rental income, allowance	3,448	3,636
Unsecured senior notes, discount	13,710	14,146
Unsecured exchangeable senior notes, discount	$0	$182
Redeemable partnership units, series two preferred units outstanding (in units)	666,116	666,116
Redeemable partnership units, common units at redemption value, if converted (in units)	874,168	874,168
Redeemable partnership units, series four preferred units outstanding (in units)	360,126	360,126
Redeemable partnership units, common units (in units)	15,583,853	15,583,370
Redeemable partnership units, long term incentive units outstanding at redemption value (in units)	1,554,353	1,455,761
General Partners' Capital Account, Units Outstanding (in units)	1,701,555	1,700,222
Limited Partners' Capital Account, Units Outstanding (in units)	151,315,756	151,282,879
Series B Cumulative Redeemable Preferred Stock [Member]	'	'
Series B Dividend Rate Percentage	5.25%	0.00%
Series B, Liquidation Preference Per Unit	$2,500	$2,500
Series B, Unitsssued	80,000	80,000
Series B, Units Outstanding	80,000	80,000

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenue	'	'
Base rent	$455,018	$373,046
Recoveries from tenants	81,934	64,319
Parking and other	24,333	23,437
Total rental revenue	561,285	460,802
Hotel revenue	8,193	8,291
Development and management services	5,216	8,733
Total revenue	574,694	477,826
Expenses	'	'
Rental	206,388	169,062
Hotel	6,797	7,044
General and administrative	29,905	45,516
Transaction costs	437	443
Impairment loss	0	4,401
Depreciation and amortization	152,245	117,409
Total expenses	395,772	343,875
Operating income	178,922	133,951
Other income (expense)	'	'
Income from unconsolidated joint ventures	2,816	8,721
Interest and other income	1,311	1,471
Gains (Losses) from investments in securities	286	735
Interest expense	-113,554	-100,433
Income from continuing operations	69,781	44,445
Discontinued operations	'	'
Income from discontinued operations	0	2,494
Gain on forgiveness of debt from discontinued operations	0	20,736
Impairment loss from discontinued operations	0	-2,852
Net income	69,781	64,823
Net income attributable to noncontrolling interests	'	'
Noncontrolling interest in property partnerships	4,354	2,574
Noncontrolling interest-redeemable preferred units	-3,208	-1,326
Net income attributable to Boston Properties Limited Partnership	$62,219	$60,923
Basic earnings per common unit attributable to Boston Properties Limited Partnership	'	'
Income from continuing operations (in dollars per share)	$0.37	$0.24
Discontinued operations (in dollars per share)	$0	$0.12
Net income (in dollars per share)	$0.37	$0.36
Weighted average number of common units outstanding (in shares)	169,841	168,750
Diluted earnings per common unit attributable to Boston Properties Limited Partnership	'	'
Income from continuing operations (in dollars per share)	$0.37	$0.24
Discontinued operations (in dollars per share)	$0	$0.12
Diluted Earnings: Net income, Per Unit Amount (in dollars per share)	$0.37	$0.36
Weighted average number of common and common equivalent units outstanding (in shares)	169,980	169,056

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'		'
Net income	$69,781		$64,823
Other comprehensive income:	'		'
Amortization of interest rate contracts	629	[1]	628	[1]
Other Comprehensive Income	629		628
Comprehensive income	70,410		65,451
Comprehensive income attributable to noncontrolling interests	-7,562		-3,900
Comprehensive income attributable to Boston Properties Limited Partnership	$62,848		$61,551
[1]	Amounts reclassified from comprehensive income primarily to interest expense within the Company's Consolidated Statements of Operations.

Consolidated_Statements_Of_Par

Consolidated Statements Of Partners' Capital (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Partners' Capital [Roll Forward]	'	'
Beginning Balance	$4,187,171	$3,330,605
Contributions	1,535	197,310
Net income allocable to general and limited partner units	58,648	54,892
Distributions	-102,050	-98,712
Accumulated other comprehensive loss	567	564
Unearned compensation	-474	1,658
Conversion of redeemable partnership units	627	272
Adjustment to reflect redeemable partnership units at redemption value	-261,862	85,104
Ending Balance	$3,884,162	$3,571,693

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net income	$69,781	$64,823
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	152,245	119,147
Non-cash compensation expense	10,380	25,783
Impairment loss	0	4,401
Income from unconsolidated joint ventures	-2,816	-8,721
Distributions of net cash flow from operations of unconsolidated joint ventures	1,431	12,921
Gains from investments in securities	-286	-735
Non-cash portion of interest expense	-7,676	10,561
Settlement of accreted debt discount on repurchases of unsecured exchangeable senior notes	-92,979	0
Gain on forgiveness of debt from discontinued operations	0	-20,736
Impairment loss from discontinued operations	0	2,852
Change in assets and liabilities:	'	'
Cash held in escrows	2,961	-297
Tenant and other receivables, net	21,652	10,690
Accrued rental income, net	-10,127	-14,295
Prepaid expenses and other assets	5,989	18,684
Accounts payable and accrued expenses	1,288	-1,172
Accrued interest payable	11,128	30,158
Other liabilities	-22,197	-7,703
Tenant leasing costs	-16,565	-8,932
Total adjustments	54,428	172,606
Net cash provided by operating activities	124,209	237,429
Cash flows from investing activities:	'	'
Acquisitions of real estate	0	-289,816
Construction in progress	-97,025	-103,178
Building and other capital improvements	-17,510	-14,162
Tenant improvements	-31,551	-24,988
Repayments of notes receivable, net	0	184
Capital contributions to unconsolidated joint ventures	0	-113
Capital distributions from unconsolidated joint ventures	113	0
Investments in securities, net	-1,099	-918
Net cash used in investing activities	-147,072	-432,991
Cash flows from financing activities:	'	'
Repayments of mortgage notes payable	-6,630	-23,687
Redemption/Repurchase of unsecured exchangeable senior notes	-654,521	0
Deferred financing costs	-18	0
Net proceeds from preferred units issuance	0	194,371
Net proceeds from equity transactions	-527	-559
Distributions	-496,330	-110,940
Proceeds from noncontrolling interest in property partnership	468	5,875
Distributions to noncontrolling interest in property partnerships	-5,143	-2,100
Net cash provided by (used in) financing activities	-1,162,701	62,960
Net decrease)in cash and cash equivalents	-1,185,564	-132,602
Cash and cash equivalents, beginning of period	2,365,137	1,041,978
Cash and cash equivalents, end of period	1,179,573	909,376
Supplemental disclosures:	'	'
Cash paid for interest	220,790	74,492
Interest capitalized	17,709	14,418
Non-cash investing and financing activities:	'	'
Additions to real estate included in accounts payable and accrued expenses	9,393	7,475
Mortgage note payable extinguished through foreclosure	0	25,000
Real estate transferred upon foreclosure	0	6,954
Land improvements contributed by noncontrolling property partnership	0	4,546
Distributions declared but not paid	114,799	110,886
Conversions of redeemable partnership units to partners' capital	627	272
Issuance of restricted securities to employees and directors	$26,534	$25,901

Organization

Organization	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization	'
	Organization
	Boston Properties Limited Partnership (the “Company”), a Delaware limited partnership, is the entity through which Boston Properties, Inc., a self-administered and self-managed real estate investment trust (“REIT”), conducts substantially all of its business and owns (either directly or through subsidiaries) substantially all of its assets. Boston Properties, Inc. is the sole general partner of the Company and at March 31, 2014 owned an approximate 89.5% (89.0% at March 31, 2013) general and limited partnership interest in the Company. Partnership interests in the Company are denominated as “common units of partnership interest” (also referred to as “OP Units”), “long term incentive units of partnership interest” (also referred to as “LTIP Units”) or “preferred units of partnership interest” (also referred to as “Preferred Units”). In addition, in February 2011 and February 2012, the Company issued LTIP Units in connection with the granting to employees of outperformance awards (also referred to as “2011 OPP Units” and “2012 OPP Units,” respectively, and collectively as “OPP Units”). On January 31, 2014, the measurement period for the Company’s 2011 OPP Unit awards expired and the Company’s total return to shareholders (“TRS”) was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. Accordingly, all 2011 OPP Unit awards were automatically forfeited (See Note 7 and 10). In February 2013 and February 2014, the Company issued LTIP Units in connection with the granting to employees of multi-year, long-term incentive program ("MYLTIP") awards (also referred to as “2013 MYLTIP Units” and “2014 MYLTIP Units,” respectively, and collectively as "MYLTIP Units"). Because the rights, preferences and privileges of OPP Units and MYLTIP Units differ from other LTIP Units granted to employees as part of the annual compensation process, unless specifically noted otherwise, all references to LTIP Units exclude OPP Units and MYLTIP Units (See Notes 7 and 10).
	Unless specifically noted otherwise, all references to OP Units exclude units held by Boston Properties, Inc. A holder of an OP Unit may present such OP Unit to the Company for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Company is obligated to redeem such OP Unit for cash equal to the value of a share of common stock of Boston Properties, Inc. (“Common Stock”) at such time. In lieu of a cash redemption, Boston Properties, Inc. may elect to acquire such OP Unit for one share of Common Stock. Because the number of shares of Common Stock outstanding at all times equals the number of OP Units that Boston Properties, Inc. owns, one share of Common Stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of Common Stock. An LTIP Unit is generally the economic equivalent of a share of restricted common stock of Boston Properties, Inc. LTIP Units, whether vested or not, will receive the same quarterly per unit distributions as OP Units, which equal per share dividends on Common Stock (See Note 8).
	At March 31, 2014, there were three series of Preferred Units outstanding (i.e., Series Two Preferred Units, Series Four Preferred Units and Series B Preferred Units).
	•	The Series Two Preferred Units bear a distribution that is set in accordance with an amendment to the partnership agreement of the Company. Each Series Two Preferred Unit may also be converted into approximately 1.312336 OP Units or redeemed for $50.00 of cash at the election of the holder thereof or the Company in accordance with the terms and conditions set forth in the applicable amendment to the partnership agreement (See Note 7).
	•	The Series Four Preferred Units are not convertible into or exchangeable for any common equity of the Company or Boston Properties, Inc., have a per unit liquidation preference of $50.00 and are entitled to receive quarterly distributions of $0.25 per unit (or an annual rate of 2.00%) (See Note 7).
	•	The Series B Preferred Units were issued to Boston Properties, Inc. on March 27, 2013 in connection with Boston Properties, Inc.'s issuance of 80,000 shares (8,000,000 depositary shares each representing 1/100th of a share) of 5.25% Series B Cumulative Redeemable Preferred Stock (the "Series B Preferred Stock"). Boston Properties, Inc. contributed the net proceeds from the offering to the Company in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock (See Note 8).
	All references herein to the Company refer to Boston Properties Limited Partnership and its consolidated subsidiaries, collectively, unless the context otherwise requires.
	Properties
	At March 31, 2014, the Company owned or had interests in a portfolio of 175 commercial real estate properties (the “Properties”) aggregating approximately 45.8 million net rentable square feet, including eight properties under construction totaling approximately 4.0 million net rentable square feet. In addition, the Company has structured parking for approximately 45,971 vehicles containing approximately 15.7 million square feet. At March 31, 2014, the Properties consist of:
	•	167 office properties, including 128 Class A office properties (including eight properties under construction) and 39 Office/Technical properties;
	•	one hotel;
	•	four retail properties; and
	•	three residential properties.
	The Company owns or controls undeveloped land parcels totaling approximately 502.5 acres.
	The Company considers Class A office properties to be centrally located buildings that are professionally managed and maintained, attract high-quality tenants and command upper-tier rental rates, and that are modern structures or have been modernized to compete with newer buildings. The Company considers Office/Technical properties to be properties that support office, research and development, laboratory and other technical uses. The Company’s definitions of Class A Office and Office/Technical properties may be different than those used by other companies.

Basis_Of_Presentation_And_Summ

Basis Of Presentation And Summary Of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Basis Of Presentation And Summary Of Significant Accounting Policies	'
	Basis of Presentation and Summary of Significant Accounting Policies
	Boston Properties, Inc. does not have any other significant assets, liabilities or operations, other than its investment in the Company, nor does it have employees of its own. The Company, not Boston Properties, Inc., generally executes all significant business relationships other than transactions involving securities of Boston Properties, Inc. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities ("VIE"s) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income.
	The accompanying interim financial statements are unaudited; however, the financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all of the disclosures required by accounting principles generally accepted in the United States of America for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair statement of the financial statements for these interim periods have been included. The results of operations for the interim periods are not necessarily indicative of the results to be obtained for other interim periods or for the full fiscal year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosure required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report in the Company’s Form 10-K for its fiscal year ended December 31, 2013. Certain prior year amounts have been reclassified to conform to the current year presentation. In the third quarter of 2013, the Company modified the presentation of expenses to operate its San Francisco and Princeton regional offices to reflect the growing activity in its San Francisco region and to have a consistent presentation across the Company. These expenses, which totaled approximately $1.9 million for the three months ended March 31, 2013 were previously included in Rental Operating Expenses and are now included in General and Administrative Expenses. In addition, beginning on January1, 2014, the properties that were historically part of the Company's Princeton region are reflected as the suburban component of the Company's New York region (See Note 11).
	The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. The Company determines the fair value of its unsecured senior notes and unsecured exchangeable senior notes using market prices. The inputs used in determining the fair value of the Company’s unsecured senior notes and unsecured exchangeable senior notes are categorized at a level 1 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company uses quoted market rates to value these instruments. However, the inputs used in determining the fair value could be categorized at a level 2 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) if trading volumes are low. The Company determines the fair value of its mortgage notes payable using discounted cash flow analyses by discounting the spread between the future contractual interest payments and hypothetical future interest payments on mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The inputs used in determining the fair value of the Company’s mortgage notes payable and mezzanine notes payable are categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs.
	Because the Company’s valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially if the Company’s estimates do not prove to be accurate. The following table presents the aggregate carrying value of the Company’s indebtedness and the Company’s corresponding estimate of fair value as of March 31, 2014 and December 31, 2013 (in thousands):
		March 31, 2014				December 31, 2013
		Carrying		Estimated		Carrying			Estimated
		Amount		Fair Value		Amount			Fair Value
	Mortgage notes payable	$	4,430,110	$	4,577,435	$	4,449,734		$	4,545,283
	Mezzanine notes payable	310,735		310,764		311,040			311,064
	Unsecured senior notes	5,836,290		6,145,060		5,835,854			6,050,517
	Unsecured exchangeable senior notes	—		—		744,880		-1	750,266
	Total	$	10,577,135	$	11,033,259	$	11,341,508		$	11,657,130
	_______________
	-1	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.
	Recent Accounting Pronouncements
	On April 10, 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") No. 2014-08, "Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity" (“ASU No. 2014-08”). ASU No. 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU No. 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU No. 2014-08 during the first quarter of 2014. The Company’s adoption of ASU No. 2014-08 did not have a material impact on its consolidated financial statements.

Real_Estate_Activity_During_th

Real Estate Activity During the Three Months Ended March 31, 2014	3 Months Ended
	Mar. 31, 2014
Real Estate [Abstract]	'
Real Estate Activity During The Nine Months Ended September 30, 2013	'
	Real Estate Activity During the Three Months Ended March 31, 2014
	Developments
	On February 10, 2014, the Company completed and fully placed in-service The Avant at Reston Town Center development project comprised of 359 apartment units and retail space aggregating approximately 355,000 square feet located in Reston, Virginia.
	Dispositions
	The Company did not have any dispositions during the three months ended March 31, 2014. The following table summarizes the income from discontinued operations for the three months ended March 31, 2013 related to One Preserve Parkway, 10 & 20 Burlington Mall Road, 1301 New York Avenue, Montvale Center and 303 Almaden Boulevard and the related gain on forgiveness of debt and impairment loss:
		For the three months ended March 31,
		2013
		(in thousands)
	Total revenue	$	7,035
	Expenses
	Operating	2,443
	Depreciation and amortization	1,738
	Total expenses	4,181
	Operating income	2,854
	Other expense
	Interest expense	360
	Income from discontinued operations	$	2,494
	Gain on forgiveness of debt from discontinued operations	$	20,736
	Impairment loss from discontinued operations	$	(2,852	)

Investments_in_Unconsolidated_

Investments in Unconsolidated Joint Ventures	3 Months Ended
	Mar. 31, 2014
Investments In Unconsolidated Joint Ventures [Abstract]	'
Investments In Unconsolidated Joint Ventures	'
	Investments in Unconsolidated Joint Ventures
	The investments in unconsolidated joint ventures consist of the following at March 31, 2014:
	Entity		Properties		Nominal %				Carrying Value of Investment
					Ownership
									(in thousands)
	Square 407 Limited Partnership		Market Square North		50	%			$	(9,758	)
	The Metropolitan Square Associates LLC		Metropolitan Square		51	%			6,236
	BP/CRF 901 New York Avenue LLC		901 New York Avenue		25	%	(1)		(2,509		)
	WP Project Developer LLC		Wisconsin Place Land and Infrastructure		33.3	%	(2)		46,944
	Boston Properties Office Value-Added Fund, L.P.		N/A		39.5	%	-3		(30		)
	Annapolis Junction NFM, LLC		Annapolis Junction		50	%	(4)		17,528
	2 GCT Venture LLC		N/A		60	%	-5		(91		)
	540 Madison Venture LLC		540 Madison Avenue		60	%			69,002
	125 West 55th Street Venture LLC		N/A		60	%	-6		944
	500 North Capitol LLC		500 North Capitol Street, NW		30	%			(910		)
									$	127,356
	_______________
	-1	The Company’s economic ownership can increase based on the achievement of certain return thresholds.
	-2	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.
	-3	The Company acquired Mountain View Research Park and Mountain View Technology Park from the Value-Added Fund on April 10, 2013.
	-4	Comprised of two buildings, one building under construction and two undeveloped land parcels (See also Note 12).
	-5	Two Grand Central Tower was sold on October 25, 2011.
	-6	125 West 55th Street was sold on May 30, 2013.
	Certain of the Company’s unconsolidated joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures at an agreed upon fair value. Under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners.
	The combined summarized balance sheets of the Company's unconsolidated joint ventures are as follows:
		March 31, 2014				31-Dec-13
		(in thousands)
	ASSETS
	Real estate and development in process, net	$	921,524			$	924,297
	Other assets	158,375				163,149
	Total assets	$	1,079,899			$	1,087,446
	LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
	Mortgage and notes payable	$	748,700			$	749,732
	Other liabilities	19,593				28,830
	Members’/Partners’ equity	311,606				308,884
	Total liabilities and members’/partners’ equity	$	1,079,899			$	1,087,446
	Company’s share of equity	$	155,807			$	154,726
	Basis differentials (1)	(28,451		)		(28,642		)
	Carrying value of the Company’s investments in unconsolidated joint ventures	$	127,356			$	126,084
	_______________
	-1	This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from impairment of investments and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level.
	The combined summarized statements of operations of the Company's unconsolidated joint ventures are as follows:
		For the three months ended March 31,
		2014				2013
		(in thousands)
	Total revenue (1)	$	38,034			$	135,650
	Expenses
	Operating	15,464				42,366
	Depreciation and amortization	9,092				39,277
	Total expenses	24,556				81,643
	Operating income	13,478				54,007
	Other expense
	Interest expense	8,012				56,234
	Net income (loss)	$	5,466			$	(2,227	)
	Company’s share of net income (loss)	$	2,625			$	(1,858	)
	Basis differential	191				444
	Elimination of inter-entity interest on partner loan	—				10,135
	Income from unconsolidated joint ventures	$	2,816			$	8,721
	_______________
	-1	Includes straight-line rent adjustments of $0.6 million and $4.0 million for the three months ended March 31, 2014 and 2013, respectively. Includes net below-market rent adjustments of $0.1 million and $20.4 million for the three months ended March 31, 2014 and 2013, respectively.

Unsecured_Exchangeable_Senior_

Unsecured Exchangeable Senior Notes Unsecured Exchangeable Senior Notes	3 Months Ended
	Mar. 31, 2014
Unsecured Exchangeable Senior Notes [Abstract]	'
Unsecured Exchangeable Senior Notes	'
	Unsecured Exchangeable Senior Notes
	On February 18, 2014, the Company repaid at maturity the $747.5 million aggregate principal amount of its 3.625% exchangeable senior notes due 2014 plus accrued and unpaid interest thereon.

Commitments_And_Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments And Contingencies	'
	Commitments and Contingencies
	General
	In the normal course of business, the Company guarantees its performance of services or indemnifies third parties against its negligence. In addition, in the normal course of business, the Company guarantees to certain tenants the obligations of its subsidiaries for the payment of tenant improvement allowances and brokerage commissions in connection with their leases and limited costs arising from delays in delivery of their premises.
	The Company has letter of credit and performance obligations of approximately $13.2 million related to lender and development requirements.
	Certain of the Company’s joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. With limited exception, under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners (See also Note 7).
	In connection with the assumption of 767 Fifth Avenue's (the General Motors Building) secured loan by the Company’s consolidated joint venture, 767 Venture, LLC, the Company guaranteed the consolidated joint venture’s obligation to fund various escrows, including tenant improvements, taxes and insurance in lieu of cash deposits. As of March 31, 2014, the maximum funding obligation under the guarantee was approximately $11.7 million. The Company earns a fee from the joint venture for providing the guarantee and has an agreement with the outside partners to reimburse the joint venture for their share of any payments made under the guarantee.
	In connection with the mortgage financing collateralized by the Company's John Hancock Tower property located in Boston, Massachusetts, the Company has agreed to guarantee approximately $21.4 million related to its obligations to provide funds for certain tenant re-leasing costs. The mortgage financing matures on January 6, 2017.
	From time to time, the Company (or the applicable joint venture) has also agreed to guarantee por
	tions of the principal, interest or other amounts in connection with other unconsolidated joint venture borrowings. In addition to the financial guarantees referenced above, the Company has agreed to customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) on certain of its unconsolidated joint venture loans.
	In 2009, the Company filed a general unsecured creditor’s claim against Lehman Brothers, Inc. for $45.3 million related to its rejection of a lease at 399 Park Avenue in New York City. On January 10, 2014, the trustee for the liquidation of Lehman Brothers allowed the Company’s claim in the amount of $45.2 million. Similar claims have recently been quoted privately within a range of $0.42 to $0.45 per $1.00 of claim. The Company is currently evaluating whether to attempt to sell the claim or wait until the trustee distributes proceeds from the Lehman estate. There can be no assurance as to the timing or amount of potential income, if any, that may ultimately be realized on the claim, whether by sale to a third party or by distribution from the trustee, and accordingly, the Company is disclosing this as a gain contingency.
	Insurance
	The Company carries insurance coverage on its properties of types and in amounts and with deductibles that it believes are in line with coverage customarily obtained by owners of similar properties. In response to the uncertainty in the insurance market following the terrorist attacks of September 11, 2001, the Federal Terrorism Risk Insurance Act (as amended, “TRIA”) was enacted in November 2002 to require regulated insurers to make available coverage for “certified” acts of terrorism (as defined by the statute). The expiration date of TRIA was extended to December 31, 2014 by the Terrorism Risk Insurance Program Reauthorization Act of 2007 (“TRIPRA”) and the Company can provide no assurance that it will be extended further. Currently, the Company’s property insurance program per occurrence limits are $1.0 billion for its portfolio insurance program, including coverage for acts of terrorism other than nuclear, biological, chemical or radiological terrorism (“Terrorism Coverage”). The Company also carries $250 million of Terrorism Coverage for 601 Lexington Avenue, New York, New York (“601 Lexington Avenue”) in excess of the $1.0 billion of coverage in the Company’s property insurance program. Certain properties, including the General Motors Building located at 767 Fifth Avenue in New York, New York (“767 Fifth Avenue”), are currently insured in separate insurance programs. The property insurance program per occurrence limits for 767 Fifth Avenue are $1.625 billion, including Terrorism Coverage, with $1.375 billion of Terrorism Coverage in excess of $250 million being provided by NYXP, LLC (“NYXP”), as a direct insurer. The Company also currently carries nuclear, biological, chemical and radiological terrorism insurance coverage for acts of terrorism certified under TRIA (“NBCR Coverage”), which is provided by IXP as a direct insurer, for the properties in our portfolio, including 767 Fifth Avenue, but excluding certain other properties owned in joint ventures with third parties or which the Company manages. The per occurrence limit for NBCR Coverage is $1.0 billion. Under TRIA, after the payment of the required deductible and coinsurance, the NBCR Coverage provided by IXP and the Terrorism Coverage provided by NYXP are backstopped by the Federal Government if the aggregate industry insured losses resulting from a certified act of terrorism exceed a “program trigger.” The program trigger is $100.0 million and the coinsurance is 15%. Under TRIPRA, if the Federal Government pays out for a loss under TRIA, it is mandatory that the Federal Government recoup the full amount of the loss from insurers offering TRIA coverage after the payment of the loss pursuant to a formula in TRIPRA. The Company may elect to terminate the NBCR Coverage if the Federal Government seeks recoupment for losses paid under TRIA, if there is a change in its portfolio or for any other reason. In the event TRIPRA is not extended beyond December 31, 2014, (i) the Company's $1.0 billion portfolio property insurance program and the $250 million of additional Terrorism Coverage for 601 Lexington Avenue will continue to provide Terrorism Coverage through the expiration of the program on March 1, 2015, (ii) the Company will evaluate alternative approaches to secure coverage for acts of terrorism thereby potentially increasing our overall cost of insurance, (iii) if such insurance is not available at commercially reasonable rates with limits equal to our current coverage or at all, the Company may not continue to have full occurrence limit coverage for acts of terrorism, (iv) the Company may not satisfy the insurance requirements under existing or future debt financings secured by individual properties, (v) the Company may not be able to obtain future debt financings secured by individual properties and (vi) the Company may cancel the insurance policies issued by IXP for the NBCR Coverage and by NYXP for the Terrorism Coverage for 767 Fifth Avenue. The Company intends to continue to monitor the scope, nature and cost of available terrorism insurance and maintain terrorism insurance in amounts and on terms that are commercially reasonable.
	The Company also currently carries earthquake insurance on its properties located in areas known to be subject to earthquakes in an amount and subject to self-insurance that the Company believes are commercially reasonable. In addition, this insurance is subject to a deductible in the amount of 5% of the value of the affected property. Specifically, the Company currently carries earthquake insurance which covers its San Francisco region (excluding 535 Mission Street and the below grade improvements for Salesforce Tower (formerly Transbay Tower)) with a $120 million per occurrence limit and a $120 million annual aggregate limit, $20 million of which is provided by IXP, as a direct insurer. The builders risk policy maintained for the development of 535 Mission Street in San Francisco includes a $15 million per occurrence and annual aggregate limit of earthquake coverage. In addition, the builders risk policy maintained for the development of the below grade improvements of the Salesforce Tower (formerly Transbay Tower) in San Francisco includes a $15 million per occurrence and annual aggregate limit of earthquake coverage. The amount of the Company’s earthquake insurance coverage may not be sufficient to cover losses from earthquakes. In addition, the amount of earthquake coverage could impact the Company’s ability to finance properties subject to earthquake risk. The Company may discontinue earthquake insurance or change the structure of its earthquake insurance program on some or all of its properties in the future if the premiums exceed the Company’s estimation of the value of the coverage.
	IXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s earthquake insurance coverage for its Greater San Francisco properties and the Company’s NBCR Coverage. NYXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s Terrorism Coverage for 767 Fifth Avenue. Currently, NYXP only insures losses which exceed the program trigger under TRIA and NYXP reinsures with a third-party insurance company any coinsurance payable under TRIA. Insofar as the Company owns IXP and NYXP, it is responsible for their liquidity and capital resources, and the accounts of IXP and NYXP are part of the Company’s consolidated financial statements. In particular, if a loss occurs which is covered by the Company’s NBCR Coverage but is less than the applicable program trigger under TRIA, IXP would be responsible for the full amount of the loss without any backstop by the Federal Government. IXP and NYXP would also be responsible for any recoupment charges by the Federal Government in the event losses are paid out and their insurance policies are maintained after the payout by the Federal Government. If the Company experiences a loss and IXP or NYXP are required to pay under their insurance policies, the Company would ultimately record the loss to the extent of the required payment. Therefore, insurance coverage provided by IXP and NYXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In addition, the Company has issued a guarantee to cover liabilities of IXP in the amount of $20.0 million.
	The mortgages on the Company's properties typically contain requirements concerning the financial ratings of the insurers who provide policies covering the property. The Company provides the lenders on a regular basis with the identity of the insurance companies in the Company's insurance programs. The ratings of some of the Company's insurers are below the rating requirements in some of the Company's loan agreements and the lenders for these loans could attempt to claim that an event of default has occurred under the loan. The Company believes it could obtain insurance with insurers which satisfy the rating requirements. Additionally, in the future, the Company's ability to obtain debt financing secured by individual properties, or the terms of such financing, may be adversely affected if lenders generally insist on ratings for insurers or amounts of insurance which are difficult to obtain or which result in a commercially unreasonable premium. There can be no assurance that a deficiency in the financial ratings of one or more of the Company's insurers will not have a material adverse effect on the Company.
	The Company continues to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism and California earthquake risk in particular, but the Company cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, for which the Company cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes or other catastrophic events, if the Company experiences a loss that is uninsured or that exceeds policy limits, the Company could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that the Company could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect the Company's business and financial condition and results of operations.

Noncontrolling_Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Noncontrolling Interests	'
	Noncontrolling Interests
	Noncontrolling interests relate to the interests in the Company not owned by Boston Properties, Inc. and interests in consolidated property partnerships not wholly-owned by the Company. As of March 31, 2014, the noncontrolling interests in the Company consisted of 15,583,853 OP Units, 1,554,353 LTIP Units, 394,590 2012 OPP Units, 314,974 2013 MYLTIP Units, 483,555 2014 MYLTIP Units, 666,116 Series Two Preferred Units (or 874,168 OP Units on an as converted basis) and 360,126 Series Four Preferred Units (none of which are convertible into OP Units) held by parties other than Boston Properties, Inc.
	Noncontrolling Interest—Redeemable Interest in Property Partnership
	On October 4, 2012, the Company completed the formation of a joint venture that owns and operates Fountain Square located in Reston, Virginia. The joint venture partner contributed the property valued at approximately $385.0 million and related mortgage indebtedness totaling approximately $211.3 million for a nominal 50% interest in the joint venture. The Company contributed cash totaling approximately $87.0 million for its nominal 50% interest, which cash was distributed to the joint venture partner. Pursuant to the joint venture agreement (i) the Company has rights to acquire the partner's nominal 50% interest and (ii) the partner has the right to cause the Company to acquire the partner's interest on January 4, 2016, in each case at a fixed price totaling approximately $102.0 million in cash. The fixed price option rights expire on January 31, 2016. The Company is consolidating this joint venture due to the Company's right to acquire the partner's nominal 50% interest. The Company initially recorded the noncontrolling interest at its acquisition-date fair value as temporary equity, due to the redemption option existing outside the control of the Company. The Company will accrete the changes in the redemption value quarterly over the period from the acquisition date to the earliest redemption date using the effective interest method.  The Company will record the accretion after the allocation of net income and distributions of cash flow to the noncontrolling interest account balance.
	The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company's Fountain Square consolidated joint venture for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	99,609
	Net loss	(106		)
	Distributions	(1,050		)
	Adjustment to reflect redeemable interest at redemption value	1,874
	Balance at March 31, 2014	$	100,327
	Balance at January 1, 2013	$	97,558
	Net loss	(525		)
	Distributions	(1,350		)
	Adjustment to reflect redeemable interest at redemption value	2,533
	Balance at March 31, 2013	$	98,216
	Noncontrolling Interest—Redeemable Preferred Units of the Company
	The Preferred Units at March 31, 2014 included 666,116 Series Two Preferred Units, which bear a preferred distribution equal to the greater of (1) the distribution which would have been paid in respect of the Series Two Preferred Unit had such Series Two Preferred Unit been converted into an OP Unit (including both regular and special distributions) or (2) 6.00% per annum on a liquidation preference of $50.00 per unit, and are convertible into OP Units at a rate of $38.10 per Preferred Unit (1.312336 OP Units for each Preferred Unit). On March 11, 2014, the Company’s general partner notified the holders of the outstanding Series Two Preferred Units that it had elected to redeem all of such Series Two Preferred Units on May 12, 2014. As a result of the Company's general partner’s election to redeem the units, all of the holders of the Series Two Preferred Units have elected to convert such units into 1.312336 OP Units, or an aggregate of 874,168 OP Units on or before May 12, 2014. Due to the holders' redemption option existing outside the control of the Company’s general partner, the Series Two Preferred Units are presented outside of permanent equity in the Company's Consolidated Balance Sheets.
	On February 18, 2014, the Company paid a distribution on its outstanding Series Two Preferred Units of $0.85302 per unit.
	Due to the redemption option and the conversion option existing outside the control of the Company, the Series Two Preferred Units are not included in Partners’ Capital and are reflected in the Consolidated Balance Sheets at an amount equivalent to the value of such units had such units been redeemed at March 31, 2014. The value of the Series Two Preferred Units, assuming all of such units had been converted and then redeemed at March 31, 2014, was approximately $100.1 million based on the closing price of Boston Properties, Inc.’s common stock of $114.53 per share on that date.
	The Preferred Units at March 31, 2014 also included 360,126 Series Four Preferred Units, which bear a preferred distribution equal to 2.00% per annum on a liquidation preference of $50.00 per unit and are not convertible into OP Units. In order to secure the performance of certain obligations by the holders, such Series Four Preferred Units are subject to forfeiture pursuant to the terms of a pledge agreement. The holders of Series Four Preferred Units have the right, at certain times and subject to certain conditions set forth in the Certificate of Designations establishing the rights, limitations and preferences of the Series Four Preferred Units, to require the Company to redeem all their units for cash at the redemption price of $50.00 per unit. The Company also has the right, at certain times and subject to certain conditions, to redeem all of the Series Four Preferred Units for cash at the redemption price of $50.00 per unit. The Series Four Preferred Units that are subject to the security interest under the pledge agreement may not be redeemed until and unless such security interest is released. The Company's first right to redeem the Series Four Preferred Units was a 30-day period beginning on August 29, 2013. Due to the holders' redemption option existing outside the control of the Company, the Series Four Preferred Units are not included in Partners' Capital in the Company's Consolidated Balance Sheets.
	On February 18, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit.
	The following table reflects the activity of the noncontrolling interests—redeemable preferred units of the Company for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	105,746
	Net income	619
	Distributions	(619		)
	Reallocation of partnership interest	12,378
	Balance at March 31, 2014	$	118,124
	Balance at January 1, 2013	$	199,378
	Net income	1,180
	Distributions	(1,180		)
	Reallocation of partnership interest	(6,208		)
	Balance at March 31, 2013	$	193,170
	Noncontrolling Interest—Common Units of the Company
	During the three months ended March 31, 2014, 18,528 OP Units were presented by the holders for redemption (including 17,191 OP Units issued upon conversion of LTIP Units) and were redeemed by Boston Properties, Inc. in exchange for an equal number of shares of Common Stock.
	At March 31, 2014, the Company had outstanding 394,590 2012 OPP Units, 314,974 2013 MYLTIP Units and 483,555 2014 MYLTIP Units. Prior to the measurement date (February 6, 2015 for 2012 OPP Units, February 4, 2016 for 2013 MYLTIP Units and February 3, 2017 for 2014 MYLTIP Units), holders of OPP Units and MYLTIP Units will be entitled to receive per unit distributions equal to one-tenth (10%) of the regular quarterly distributions payable on an OP Unit, but will not be entitled to receive any special distributions. After the measurement date, the number of OPP Units and MYLTIP Units, both vested and unvested, that OPP and MYLTIP award recipients have earned, if any, based on the establishment of a performance pool, will be entitled to receive distributions in an amount per unit equal to distributions, both regular and special, payable on an OP Unit.
	On January 31, 2014, the measurement period for the Company’s 2011 OPP Unit awards expired and Boston Properties, Inc.'s TRS was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. Accordingly, all 2011 OPP Unit awards were automatically forfeited.
	On January 29, 2014, the Company paid a special cash distribution on the OP Units and LTIP Units in the amount of $2.25 per unit, a regular cash distribution on the OP Units and LTIP Units in the amount of $0.65 per unit, and a distribution on the 2011 OPP Units, 2012 OPP Units and 2013 MYLTIP Units in the amount of $0.065 per unit, to holders of record as of the close of business on December 31, 2013. The special cash distribution was in addition to the regular quarterly distribution on the OP Units and LTIP Units. Holders of the 2011 OPP Units, 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units are not entitled to receive any special distributions. Holders of Series Two Preferred Units will participate in the special cash distributions in connection with their conversion to OP Units in May 2014 as provided in the Company's partnership agreement. On March 18, 2014, Boston Properties, Inc., as general partner of the Company, declared a distribution on the OP Units and LTIP Units in the amount of $0.65 per unit and a distribution on the 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units in the amount of $0.065 per unit, in each case payable on April 30, 2014 to holders of record as of the close of business on March 31, 2014.
	The following table reflects the activity of the noncontrolling interests—redeemable common units for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	1,710,218
	Contributions	23,379
	Net income	6,160
	Distributions	(11,218		)
	Conversion of redeemable partnership units	(627		)
	Unearned compensation	(14,619		)
	Accumulated other comprehensive loss	62
	Adjustment to reflect redeemable partnership units at redemption value	249,484
	Balance at March 31, 2014	$	1,962,839
	Balance at January 1, 2013	$	1,836,522
	Contributions	22,403
	Net income	6,177
	Distributions	(11,446		)
	Conversion of redeemable partnership units	(272		)
	Unearned compensation	(5,859		)
	Accumulated other comprehensive loss	64
	Adjustment to reflect redeemable partnership units at redemption value	(78,896		)
	Balance at March 31, 2013	$	1,768,693
	Pursuant to the Company’s partnership agreement, certain limited partners in the Company have the right to redeem all or any portion of their interest for cash from the Company. However, Boston Properties, Inc. may elect to acquire the limited partner’s interest by issuing its Common Stock in exchange for the interest. The amount of cash to be paid to the limited partner if the redemption right is exercised and Boston Properties, Inc. does not elect to issue its Common Stock is based on the trading price of Boston Properties, Inc.’s common stock at that time. Due to the redemption option existing outside the control of the Company, such limited partners’ units are not included in Partners’ Capital. The value of the OP Units not owned by Boston Properties, Inc. (including LTIP Units assuming that all conditions had been met for the conversion thereof), assuming all of such units had been redeemed at March 31, 2014 was approximately $2.0 billion based on the closing price of Boston Properties, Inc.’s common stock of $114.53 per share.
	Noncontrolling Interests—Property Partnerships
	The noncontrolling interests in property partnerships consist of the outside equity interests in ventures that are consolidated with the financial results of the Company because the Company exercises control over the entities that own the properties. The equity interests in these ventures that are not owned by the Company, totaling approximately $725.1 million at March 31, 2014 and approximately $726.1 million at December 31, 2013, are included in Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets.
	On February 7, 2013, the partner in the Company's Salesforce Tower (formerly Transbay Tower) joint venture issued a notice that it was electing under the joint venture agreement to reduce its nominal ownership interest in the venture from 50% to 5%. On February 26, 2013, the Company issued a notice to the partner electing to proceed with the venture on that basis. As a result, the Company has a 95% nominal interest in and is consolidating the joint venture. Under the joint venture agreement, if certain return thresholds are achieved the partner will be entitled to an additional promoted interest. In addition, if the Company elects to fund the construction of Salesforce Tower without a construction loan (or a construction loan of less than 50% of project costs), then the partner has the option to require the Company to fund up to 2.5% of the total project costs (i.e., of 50% of the partner's 5% interest in the venture) in the form of a loan to the partner.  This loan would bear interest at the then prevailing market construction loan interest rates. Also, under the agreement, (1) the partner has the right to cause the Company to purchase the partner's interest after the defined stabilization date and (2) the Company has the right to acquire the partner's interest on the third anniversary of the stabilization date, in each case at an agreed upon purchase price or appraised value.
	On May 31, 2013, the Company's two joint venture partners in 767 Venture, LLC (the entity that owns 767 Fifth Avenue(the General Motors Building) in New York City) transferred all of their interests in the joint venture to third parties. In connection with the transfer, the Company and its new joint venture partners modified the Company's relative decision making authority and consent rights with respect to the joint venture's assets and operations. These changes resulted in the Company having sufficient financial and operating control over 767 Venture, LLC such that the Company now accounts for the assets, liabilities and operations of 767 Venture, LLC on a consolidated basis in its financial statements instead of under the equity method of accounting. Upon consolidation, the Company recognized the new joint venture partners' aggregate 40% equity interest at its aggregate fair value of approximately $480.9 million within Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets.
	On October 9, 2013, the Company completed the sale of a 45% ownership interest in its Times Square Tower property for a gross sale price of $684.0 million in cash. Net cash proceeds totaled approximately $673.1 million, after the payment of transaction costs. In connection with the sale, the Company formed a joint venture with the buyer and will provide customary property management and leasing services to the joint venture. Times Square Tower is an approximately 1,246,000 net rentable square foot Class A office tower located in New York City. The transaction did not qualify as a sale of real estate for financial reporting purposes because the Company continues to control the joint venture and will therefore continue to account for the entity on a consolidated basis in its financial statements. The Company has accounted for the transaction as an equity transaction and has recognized noncontrolling interest in its consolidated balance sheets totaling approximately $243.5 million, which is equal to 45% of the carrying value of the total equity of the property immediately prior to the transaction.
	The following table reflects the activity of the noncontrolling interests in property partnerships for the three months ended March 31, 2014 and 2013 (in thousands):
Balance at January 1, 2014	$	726,132
Capital contributions	468
Net income	2,586
Distributions	(4,093		)
Balance at March 31, 2014	$	725,093
Balance at January 1, 2013	$	(1,964	)
Capital contributions	10,421
Net income	566
Distributions	(750		)
Balance at March 31, 2013	$	8,273

Partners_Capital

Partners' Capital	3 Months Ended
	Mar. 31, 2014
Partners' Capital [Abstract]	'
Partners' Capital	'
	Partners’ Capital
	As of March 31, 2014, Boston Properties, Inc. owned 1,701,555 general partnership units and 151,315,756 limited partnership units.
	As of March 31, 2014, approximately $305.3 million remained available for issuance under Boston Properties, Inc.'s $600 million “at the market” stock offering program. No shares were issued under the “at the market” stock offering program during the three months ended March 31, 2014.
	During the three months ended March 31, 2014, Boston Properties, Inc. acquired 18,528 OP Units in connection with the redemption of an equal number of redeemable OP Units from third parties.
	On January 29, 2014, the Company paid a special cash distribution and regular quarterly distribution aggregating $2.90 per OP Unit to unitholders of record as of the close of business on December 31, 2013. On March 18, 2014, Boston Properties, Inc.'s Board of Directors declared a distribution of $0.65 per OP Unit payable on April 30, 2014 to unitholders of record as of the close of business on March 31, 2014.
	As of March 31, 2014, Boston Properties, Inc. had 80,000 shares (8,000,000 depositary shares each representing 1/100th of a share) outstanding of its 5.25% Series B Cumulative Redeemable Preferred Stock, with a liquidation preference of $2,500.00 per share ($25.00 per depositary share). Boston Properties, Inc. contributed the net proceeds of the offering to the Company in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock. Boston Properties, Inc. will pay cumulative cash dividends on the Series B Preferred Stock at a rate of 5.25% per annum of the $2,500.00 liquidation preference per share. Boston Properties, Inc. may not redeem the Series B Preferred Stock prior to March 27, 2018, except in certain circumstances relating to the preservation of Boston Properties, Inc.'s REIT status. On or after March 27, 2018, Boston Properties, Inc., at its option, may redeem the Series B Preferred Stock for a cash redemption price of $2,500.00 per share ($25.00 per depositary share), plus all accrued and unpaid dividends. The Series B Preferred Stock is not redeemable by the holders, has no maturity date and is not convertible into any other security of Boston Properties, Inc., the Company or its affiliates.
	On February 18, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On March 18, 2014, Boston Properties, Inc.'s Board of Directors declared a distribution of $32.8125 per Series B Preferred Unit payable on May 15, 2014 to shareholders of record as of the close of business on May 5, 2014.

Earnings_Per_Common_Unit

Earnings Per Common Unit	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings Per Common Unit	'
	Earnings Per Common Unit
	The following table provides a reconciliation of both the net income attributable to Boston Properties Limited Partnership and the number of common units used in the computation of basic earnings per common unit, which is calculated by dividing net income attributable to Boston Properties Limited Partnership by the weighted-average number of common units outstanding during the period. The terms of the Series Two Preferred Units enable the holders to obtain OP Units of the Company and as a result these are considered participating securities. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also participating securities. As such, unvested restricted common stock of Boston Properties, Inc. and the Company’s LTIP Units, OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic earnings per common unit using the two-class method. Participating securities are included in the computation of diluted earnings per common unit using the if-converted method if the impact is dilutive.  Because the OPP Units and MYLTIP Units require Boston Properties, Inc. to outperform absolute and relative return thresholds, unless such thresholds have been met by the end of the applicable reporting period, the Company excludes such units from the diluted earnings per common unit calculation. Other potentially dilutive common units and the related impact on earnings are considered when calculating diluted earnings per common unit. Included in the number of units (the denominator) below are approximately 16,811,000 and 17,104,000 redeemable common units for the three months ended March 31, 2014 and 2013, respectively.
		For the three months ended March 31, 2014
		Income		Units	Per Unit
		(Numerator)		(Denominator)	Amount
		(in thousands, except for per unit amounts)
	Basic Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	62,219	169,841	$	0.37
	Effect of Dilutive Securities:
	Stock Based Compensation	—		139	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	62,219	169,980	$	0.37
		For the three months ended March 31, 2013
		Income		Units	Per Unit
		(Numerator)		(Denominator)	Amount
		(in thousands, except for per unit amounts)
	Basic Earnings:
	Income from continuing operations attributable to Boston Properties Limited Partnership	$	40,545	168,750	$	0.24
	Discontinued operations attributable to Boston Properties Limited Partnership	20,378		—	0.12
	Net income attributable to Boston Properties Limited Partnership	$	60,923	168,750	$	0.36
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—		306	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	60,923	169,056	$	0.36

Stock_Option_and_Incentive_Pla

Stock Option and Incentive Plan	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock Option and Incentive Plan	'
	Stock Option and Incentive Plan
	On January 27, 2014, Boston Properties, Inc.'s Compensation Committee approved the 2014 MYLTIP awards under Boston Properties, Inc.'s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2014 MYLTIP awards utilize TRS over a three-year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards, if any, will be based on Boston Properties, Inc.'s TRS relative to (i) the Cohen & Steers Realty Majors Portfolio Index (50% weight) and (ii) the NAREIT Office Index adjusted to exclude Boston Properties, Inc. (50% weight). Earned awards will range from $0 to a maximum of approximately $40.2 million depending on the Boston Properties, Inc.'s TRS relative to the two indices, with four tiers (threshold: approximately $6.7 million; target: approximately $13.4 million; high: approximately $26.8 million; and exceptional: approximately $40.2 million) and linear interpolation between tiers. Earned awards measured on the basis of relative TRS performance are subject to an absolute TRS component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.'s annualized TRS is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.'s annualized TRS is more than 12% even though on a relative basis alone Boston Properties, Inc.'s TRS would not result in any earned awards.
	Earned awards (if any) will vest 50% on February 3, 2017 and 50% on February 3, 2018, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 3, 2017, earned awards will be calculated as of the date of the change of control based upon performance through such date as measured against performance hurdles (without proration). The 2014 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units.
	Under the Financial Accounting Standards Board's Accounting Standards Codification (“ASC”) 718 “Compensation-Stock Compensation” the 2014 MYLTIP awards have an aggregate value of approximately $12.7 million, which amount will generally be amortized into earnings over the four-year plan period under the graded vesting method.
	On January 31, 2014, the measurement period for Boston Properties Inc.'s 2011 OPP Unit awards expired and Boston Properties Inc.'s TRS was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. Accordingly, all 2011 OPP Unit awards were automatically forfeited.
	During the three months ended March 31, 2014, Boston Properties, Inc. issued 21,455 shares of restricted common stock, no non-qualified stock options and the Company issued 121,567 LTIP Units and 485,459 2014 MYLTIP Units to employees under the 2012 Plan. Employees paid $0.01 per share of restricted common stock and $0.25 per LTIP Unit and 2014 MYLTIP Unit. An LTIP Unit is generally the economic equivalent of a share of restricted stock in Boston Properties, Inc. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets. Grants of restricted stock and LTIP Units to employees vest in four equal annual installments. Restricted stock is measured at fair value on the date of grant based on the number of shares granted, as adjusted for forfeitures, and the closing price of Boston Properties, Inc.’s Common Stock on the date of grant as quoted on the New York Stock Exchange. Such value is recognized as an expense ratably over the corresponding employee service period. The shares of restricted stock granted during the three months ended March 31, 2014 were valued at approximately $2.3 million ($108.09 per share). The LTIP Units granted were valued at approximately $12.2 million ($100.16 per unit weighted-average fair value) using a Monte Carlo simulation method model. The per unit fair value of each LTIP Unit granted was estimated on the date of grant using the following assumptions: an expected life of 5.7 years, a risk-free interest rate of 1.84% and an expected price volatility of 27%. As the 2011 OPP Units, 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units are subject to both a service condition and a market condition, the Company recognizes the compensation expense related to the 2011 OPP Units, 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units under the graded vesting attribution method. Under the graded vesting attribution method, each portion of the award that vests at a different date is accounted for as a separate award and recognized over the period appropriate to that portion so that the compensation cost for each portion should be recognized in full by the time that portion vests. Dividends paid on both vested and unvested shares of restricted stock are charged directly to Partners’ Capital in the Consolidated Balance Sheets. Aggregate stock-based compensation expense associated with restricted stock, non-qualified stock options, LTIP Units, 2011 OPP Units, 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units was approximately $9.9 million and $25.5 million for the three months ended March 31, 2014 and 2013, respectively. On January 31, 2014, the measurement period for the Company’s 2011 OPP Awards expired and the Company’s TRS was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Awards. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million. For the three months ended March 31, 2013, stock-based compensation expense includes approximately $16.9 million consisting of the acceleration of the expense of Boston Properties, Inc.’s Executive Chairman’s stock-based compensation awards and the stock-based compensation awards associated with his transition benefits agreement related to Boston Properties, Inc.'s succession planning. At March 31, 2014, there was $24.9 million of unrecognized compensation expense related to unvested restricted stock and LTIP Units and $20.6 million of unrecognized compensation expense related to unvested 2012 OPP Units, 2013 MYLTIP Units and 2014 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 3.3 years.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	Segment Information
	The Company’s segments are based on the Company’s method of internal reporting which classifies its operations by both geographic area and property type. Beginning on January 1, 2014, the properties that were historically part of the Princeton region are reflected as the suburban component of the New York region. The operations for the Princeton region, including the reclassification between Rental Operating Expenses and General and Administrative Expenses for the three months ended March 31, 2013 as detailed below, have been included in the New York region. The Company’s segments by geographic area are Boston, New York, San Francisco and Washington, DC. Segments by property type include: Class A Office, Office/Technical, Residential and Hotel.
	Asset information by segment is not reported because the Company does not use this measure to assess performance. Therefore, depreciation and amortization expense is not allocated among segments. Interest and other income, development and management services income, general and administrative expenses, transaction costs, impairment loss, interest expense, depreciation and amortization expense, gains from investments in securities, income from unconsolidated joint ventures, discontinued operations and noncontrolling interests are not included in Net Operating Income as internal reporting addresses these items on a corporate level.
	Net Operating Income is not a measure of operating results or cash flows from operating activities as measured by accounting principles generally accepted in the United States of America, and it is not indicative of cash available to fund cash needs and should not be considered an alternative to cash flows as a measure of liquidity. All companies may not calculate Net Operating Income in the same manner. The Company considers Net Operating Income to be an appropriate supplemental measure to net income because it helps both investors and management to understand the core operations of the Company’s properties.
	In the third quarter of 2013, the Company modified the presentation of expenses to operate its San Francisco and Princeton regional offices to reflect the growing activity in its San Francisco region and to have a consistent presentation across the Company. For San Francisco these expenses, which totaled approximately $1.5 million for the three months ended March 31, 2013, and for Princeton these expenses, which totaled approximately $0.4 million for the three months ended March 31, 2013, were previously included in Rental Operating Expenses and are now included in General and Administrative Expenses.
	On May 31, 2013, the Company's two joint venture partners in 767 Venture, LLC (the entity that owns 767 Fifth Avenue (the General Motors Building) located in New York City) transferred all of their interests in the joint venture to third parties. Effective as of May 31, 2013, the Company accounts for the assets, liabilities and operations of 767 Venture, LLC on a consolidated basis in its financial statements instead of under the equity method of accounting Upon consolidation, the operations for this building are included in the New York region.
	Information by geographic area and property type (dollars in thousands):
	For the three months ended March 31, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	170,942		$	217,308		$	54,608		$	97,048		$	539,906
	Office/Technical	5,820			—			6,217			3,660			15,697
	Residential	1,163			—			—			4,519			5,682
	Hotel	8,193			—			—			—			8,193
	Total	186,118			217,308			60,825			105,227			569,478
	% of Grand Totals	32.68		%	38.16		%	10.68		%	18.48		%	100		%
	Rental Expenses:
	Class A Office	71,398			74,371			19,313			33,439			198,521
	Office/Technical	1,689			—			1,214			1,202			4,105
	Residential	448			—			—			3,314			3,762
	Hotel	6,797			—			—			—			6,797
	Total	80,332			74,371			20,527			37,955			213,185
	% of Grand Totals	37.68		%	34.89		%	9.63		%	17.8		%	100		%
	Net operating income	$	105,786		$	142,937		$	40,298		$	67,272		$	356,293
	% of Grand Totals	29.69		%	40.12		%	11.31		%	18.88		%	100		%
	For the three months ended March 31, 2013:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	160,824		$	138,523		$	52,671		$	93,359		$	445,377
	Office/Technical	5,653			—			151			4,043			9,847
	Residential	1,067			—			—			4,511			5,578
	Hotel	8,291			—			—			—			8,291
	Total	175,835			138,523			52,822			101,913			469,093
	% of Grand Totals	37.48		%	29.53		%	11.26		%	21.73		%	100		%
	Rental Expenses:
	Class A Office	65,287			49,088			18,373			30,755			163,503
	Office/Technical	1,787			—			35			1,004			2,826
	Residential	443			—			—			2,290			2,733
	Hotel	7,044			—			—			—			7,044
	Total	74,561			49,088			18,408			34,049			176,106
	% of Grand Totals	42.35		%	27.87		%	10.45		%	19.33		%	100		%
	Net operating income	$	101,274		$	89,435		$	34,414		$	67,864		$	292,987
	% of Grand Totals	34.57		%	30.53		%	11.75		%	23.15		%	100		%
	The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership:
		Three months ended
		March 31,
		2014			2013
		(in thousands)
	Net Operating Income	$	356,293		$	292,987
	Add:
	Development and management services income	5,216			8,733
	Income from unconsolidated joint ventures	2,816			8,721
	Interest and other income	1,311			1,471
	Gains from investments in securities	286			735
	Income from discontinued operations	—			2,494
	Gain on forgiveness of debt from discontinued operations	—			20,736
	Less:
	General and administrative expense	29,905			45,516
	Transaction costs	437			443
	Depreciation and amortization expense	152,245			117,409
	Interest expense	113,554			100,433
Impairment loss	—			4,401
Impairment loss from discontinued operations	—			2,852
Noncontrolling interest in property partnerships	4,354			2,574
Noncontrolling interest—redeemable preferred units	3,208			1,326
Net income attributable to Boston Properties Limited Partnership	$	62,219		$	60,923

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	On April 10, 2014, a consolidated joint venture in which the Company has a 95% interest signed a lease with salesforce.com for 714,000 square feet at the new Salesforce Tower (formerly Transbay Tower), the 1.4 million square foot, 61-story Class A office development project currently under construction at 415 Mission Street in the South Financial District of San Francisco, California. In conjunction with the lease signing, the Company has committed to construct the building.
	On April 10, 2014, the Company entered into a joint venture with an unrelated third party to acquire a parcel of land located at 501 K Street in Washington, DC. The Company anticipates the land parcel will accommodate an approximate 520,000 square foot Class A office property to be developed in the future. The joint venture partner contributed the land for its 50% interest in the joint venture and the Company contributed cash of approximately $39.0 million for its 50% interest.
	On April 30, 2014, the Company's partner in its Annapolis Junction joint venture contributed a parcel of land and improvements and the Company contributed cash of approximately $5.4 million. The Company has a 50% interest in this joint venture. The joint venture has commenced construction of Annapolis Junction Building Eight, which when completed will consist of a Class A office property with approximately 125,000 net rentable square feet located in Annapolis, Maryland.

Basis_Of_Presentation_And_Summ1

Basis Of Presentation And Summary Of Significant Accounting Policies Recent Accounting Pronouncement (Policies)	3 Months Ended
	Mar. 31, 2014
Recent Accounting Pronouncement [Abstract]	'
Recent Accounting Pronouncement [Policy Text Block]	'
	Recent Accounting Pronouncements
	On April 10, 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") No. 2014-08, "Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity" (“ASU No. 2014-08”). ASU No. 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU No. 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU No. 2014-08 during the first quarter of 2014. The Company’s adoption of ASU No. 2014-08 did not have a material impact on its consolidated financial statements.

Basis_Of_Presentation_And_Summ2

Basis Of Presentation And Summary Of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value	'
	The following table presents the aggregate carrying value of the Company’s indebtedness and the Company’s corresponding estimate of fair value as of March 31, 2014 and December 31, 2013 (in thousands):
		March 31, 2014				December 31, 2013
		Carrying		Estimated		Carrying			Estimated
		Amount		Fair Value		Amount			Fair Value
	Mortgage notes payable	$	4,430,110	$	4,577,435	$	4,449,734		$	4,545,283
	Mezzanine notes payable	310,735		310,764		311,040			311,064
	Unsecured senior notes	5,836,290		6,145,060		5,835,854			6,050,517
	Unsecured exchangeable senior notes	—		—		744,880		-1	750,266
	Total	$	10,577,135	$	11,033,259	$	11,341,508		$	11,657,130
	_______________
	-1	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at December 31, 2013.

Real_Estate_Activity_During_th1

Real Estate Activity During the Three Months Ended March 31, 2014 (Tables)	3 Months Ended
	Mar. 31, 2014
Business Acquisition [Line Items]	'
Summary of the Discontinued Operations Related To Montvale Center , 303 Almaden Blvd, 1301 New York Avenue and Bedford Business Park	'
		For the three months ended March 31,
		2013
		(in thousands)
	Total revenue	$	7,035
	Expenses
	Operating	2,443
	Depreciation and amortization	1,738
	Total expenses	4,181
	Operating income	2,854
	Other expense
	Interest expense	360
	Income from discontinued operations	$	2,494
	Gain on forgiveness of debt from discontinued operations	$	20,736
	Impairment loss from discontinued operations	$	(2,852	)

Investments_in_Unconsolidated_1

Investments in Unconsolidated Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2014
Investments In Unconsolidated Joint Ventures [Abstract]	'
Investments In Unconsolidated Joint Ventures	'
	The investments in unconsolidated joint ventures consist of the following at March 31, 2014:
	Entity		Properties		Nominal %				Carrying Value of Investment
					Ownership
									(in thousands)
	Square 407 Limited Partnership		Market Square North		50	%			$	(9,758	)
	The Metropolitan Square Associates LLC		Metropolitan Square		51	%			6,236
	BP/CRF 901 New York Avenue LLC		901 New York Avenue		25	%	(1)		(2,509		)
	WP Project Developer LLC		Wisconsin Place Land and Infrastructure		33.3	%	(2)		46,944
	Boston Properties Office Value-Added Fund, L.P.		N/A		39.5	%	-3		(30		)
	Annapolis Junction NFM, LLC		Annapolis Junction		50	%	(4)		17,528
	2 GCT Venture LLC		N/A		60	%	-5		(91		)
	540 Madison Venture LLC		540 Madison Avenue		60	%			69,002
	125 West 55th Street Venture LLC		N/A		60	%	-6		944
	500 North Capitol LLC		500 North Capitol Street, NW		30	%			(910		)
									$	127,356
	_______________
	-1	The Company’s economic ownership can increase based on the achievement of certain return thresholds.
	-2	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.
	-3	The Company acquired Mountain View Research Park and Mountain View Technology Park from the Value-Added Fund on April 10, 2013.
	-4	Comprised of two buildings, one building under construction and two undeveloped land parcels (See also Note 12).
	-5	Two Grand Central Tower was sold on October 25, 2011.
	-6	125 West 55th Street was sold on May 30, 2013.
Balance Sheets Of The Unconsolidated Joint Ventures	'
	The combined summarized balance sheets of the Company's unconsolidated joint ventures are as follows:
		March 31, 2014				31-Dec-13
		(in thousands)
	ASSETS
	Real estate and development in process, net	$	921,524			$	924,297
	Other assets	158,375				163,149
	Total assets	$	1,079,899			$	1,087,446
	LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
	Mortgage and notes payable	$	748,700			$	749,732
	Other liabilities	19,593				28,830
	Members’/Partners’ equity	311,606				308,884
	Total liabilities and members’/partners’ equity	$	1,079,899			$	1,087,446
	Company’s share of equity	$	155,807			$	154,726
	Basis differentials (1)	(28,451		)		(28,642		)
	Carrying value of the Company’s investments in unconsolidated joint ventures	$	127,356			$	126,084
	_______________
	-1	This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from impairment of investments and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level.
Statements Of Operations Of The Joint Ventures	'
	The combined summarized statements of operations of the Company's unconsolidated joint ventures are as follows:
		For the three months ended March 31,
		2014				2013
		(in thousands)
	Total revenue (1)	$	38,034			$	135,650
	Expenses
	Operating	15,464				42,366
	Depreciation and amortization	9,092				39,277
	Total expenses	24,556				81,643
	Operating income	13,478				54,007
	Other expense
	Interest expense	8,012				56,234
	Net income (loss)	$	5,466			$	(2,227	)
	Company’s share of net income (loss)	$	2,625			$	(1,858	)
	Basis differential	191				444
	Elimination of inter-entity interest on partner loan	—				10,135
	Income from unconsolidated joint ventures	$	2,816			$	8,721
	_______________
	-1	Includes straight-line rent adjustments of $0.6 million and $4.0 million for the three months ended March 31, 2014 and 2013, respectively. Includes net below-market rent adjustments of $0.1 million and $20.4 million for the three months ended March 31, 2014 and 2013, respectively.

Noncontrolling_Interests_Table

Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 2014
Noncontrolling Interest [Abstract]	'
Schedule of Redeemable Interest in Property Partnerships [Table Text Block]	'
	he following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company's Fountain Square consolidated joint venture for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	99,609
	Net loss	(106		)
	Distributions	(1,050		)
	Adjustment to reflect redeemable interest at redemption value	1,874
	Balance at March 31, 2014	$	100,327
	Balance at January 1, 2013	$	97,558
	Net loss	(525		)
	Distributions	(1,350		)
	Adjustment to reflect redeemable interest at redemption value	2,533
	Balance at March 31, 2013	$	98,216
Schedule Of Series Two Preferred Units	'
	The following table reflects the activity of the noncontrolling interests—redeemable preferred units of the Company for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	105,746
	Net income	619
	Distributions	(619		)
	Reallocation of partnership interest	12,378
	Balance at March 31, 2014	$	118,124
	Balance at January 1, 2013	$	199,378
	Net income	1,180
	Distributions	(1,180		)
	Reallocation of partnership interest	(6,208		)
	Balance at March 31, 2013	$	193,170
Noncontrolling Interests-Redeemable Common Units	'
	The following table reflects the activity of the noncontrolling interests—redeemable common units for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	1,710,218
	Contributions	23,379
	Net income	6,160
	Distributions	(11,218		)
	Conversion of redeemable partnership units	(627		)
	Unearned compensation	(14,619		)
	Accumulated other comprehensive loss	62
	Adjustment to reflect redeemable partnership units at redemption value	249,484
	Balance at March 31, 2014	$	1,962,839
	Balance at January 1, 2013	$	1,836,522
	Contributions	22,403
	Net income	6,177
	Distributions	(11,446		)
	Conversion of redeemable partnership units	(272		)
	Unearned compensation	(5,859		)
	Accumulated other comprehensive loss	64
	Adjustment to reflect redeemable partnership units at redemption value	(78,896		)
	Balance at March 31, 2013	$	1,768,693
Noncontrolling Interests-Property Partnerships	'
	The following table reflects the activity of the noncontrolling interests in property partnerships for the three months ended March 31, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	726,132
	Capital contributions	468
	Net income	2,586
	Distributions	(4,093		)
	Balance at March 31, 2014	$	725,093
	Balance at January 1, 2013	$	(1,964	)
	Capital contributions	10,421
	Net income	566
	Distributions	(750		)
	Balance at March 31, 2013	$	8,273

Earnings_Per_Common_Unit_Table

Earnings Per Common Unit (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Computation Of Basic And Diluted Earnings Per Unit	'
	approximately 16,811,000 and 17,104,000 redeemable common units for the three months ended March 31, 2014 and 2013, respectively.
		For the three months ended March 31, 2014
		Income		Units	Per Unit
		(Numerator)		(Denominator)	Amount
		(in thousands, except for per unit amounts)
	Basic Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	62,219	169,841	$	0.37
	Effect of Dilutive Securities:
	Stock Based Compensation	—		139	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	62,219	169,980	$	0.37
		For the three months ended March 31, 2013
		Income		Units	Per Unit
		(Numerator)		(Denominator)	Amount
		(in thousands, except for per unit amounts)
	Basic Earnings:
	Income from continuing operations attributable to Boston Properties Limited Partnership	$	40,545	168,750	$	0.24
	Discontinued operations attributable to Boston Properties Limited Partnership	20,378		—	0.12
	Net income attributable to Boston Properties Limited Partnership	$	60,923	168,750	$	0.36
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—		306	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	60,923	169,056	$	0.36

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Schedule Of Segment Information By Geographic Area And Property Type	'
	Information by geographic area and property type (dollars in thousands):
	For the three months ended March 31, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	170,942		$	217,308		$	54,608		$	97,048		$	539,906
	Office/Technical	5,820			—			6,217			3,660			15,697
	Residential	1,163			—			—			4,519			5,682
	Hotel	8,193			—			—			—			8,193
	Total	186,118			217,308			60,825			105,227			569,478
	% of Grand Totals	32.68		%	38.16		%	10.68		%	18.48		%	100		%
	Rental Expenses:
	Class A Office	71,398			74,371			19,313			33,439			198,521
	Office/Technical	1,689			—			1,214			1,202			4,105
	Residential	448			—			—			3,314			3,762
	Hotel	6,797			—			—			—			6,797
	Total	80,332			74,371			20,527			37,955			213,185
	% of Grand Totals	37.68		%	34.89		%	9.63		%	17.8		%	100		%
	Net operating income	$	105,786		$	142,937		$	40,298		$	67,272		$	356,293
	% of Grand Totals	29.69		%	40.12		%	11.31		%	18.88		%	100		%
	For the three months ended March 31, 2013:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	160,824		$	138,523		$	52,671		$	93,359		$	445,377
	Office/Technical	5,653			—			151			4,043			9,847
	Residential	1,067			—			—			4,511			5,578
	Hotel	8,291			—			—			—			8,291
	Total	175,835			138,523			52,822			101,913			469,093
	% of Grand Totals	37.48		%	29.53		%	11.26		%	21.73		%	100		%
	Rental Expenses:
	Class A Office	65,287			49,088			18,373			30,755			163,503
	Office/Technical	1,787			—			35			1,004			2,826
	Residential	443			—			—			2,290			2,733
	Hotel	7,044			—			—			—			7,044
	Total	74,561			49,088			18,408			34,049			176,106
	% of Grand Totals	42.35		%	27.87		%	10.45		%	19.33		%	100		%
	Net operating income	$	101,274		$	89,435		$	34,414		$	67,864		$	292,987
	% of Grand Totals	34.57		%	30.53		%	11.75		%	23.15		%	100		%
Schedule Of Reconciliation Of Net Operating Income To Net Income	'
	The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership:
		Three months ended
		March 31,
		2014			2013
		(in thousands)
	Net Operating Income	$	356,293		$	292,987
	Add:
	Development and management services income	5,216			8,733
	Income from unconsolidated joint ventures	2,816			8,721
	Interest and other income	1,311			1,471
	Gains from investments in securities	286			735
	Income from discontinued operations	—			2,494
	Gain on forgiveness of debt from discontinued operations	—			20,736
	Less:
	General and administrative expense	29,905			45,516
	Transaction costs	437			443
	Depreciation and amortization expense	152,245			117,409
	Interest expense	113,554			100,433
	Impairment loss	—			4,401
	Impairment loss from discontinued operations	—			2,852
	Noncontrolling interest in property partnerships	4,354			2,574
	Noncontrolling interest—redeemable preferred units	3,208			1,326
	Net income attributable to Boston Properties Limited Partnership	$	62,219		$	60,923

Organization_Details

Organization (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Y

Commercial Real Estate Properties [Member]

Total Properties Under Construction [Member]

Total Office Properties [Member]

Class A Office Properties [Member]

Office Properties Under Construction [Member]

Office/Technical Properties [Member]

Hotel Properties [Member]

Retail Properties [Member]

Residential Properties [Member]

series four preferred units [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series Two Preferred Units [Member]

Series B Preferred Units [Member]

depositary shares [Member]

sqft

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Real_Estate_Properties

Series B Cumulative Redeemable Preferred Stock [Member]

Vehicles

sqft

sqft

acre

Real Estate Properties [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

General and limited partnership interest in the operating partnership (percent)

89.50%

89.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restriction on redemption of OP units from date of issuance (years)

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

One OP unit is equivalent to one share of Common Stock (in shares)

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

OP unit conversion rate (in shares)

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Series B, Units Outstanding

'

'

'

'

'

'

'

'

'

'

'

'

80,000

80,000

'

80,000

8,000,000

Ratio of depository shares to shares of Series B Preferred Stock

'

'

'

'

'

'

'

'

'

'

'

'

0.01

'

'

'

'

Series B, Dividend Rate, Percentage

'

'

'

'

'

'

'

'

'

'

'

'

5.25%

'

'

'

'

Preferred Units Liquidation Preference

'

'

'

'

'

'

'

'

'

'

'

$50

'

'

$50

'

'

Number of series of preferred units outstanding

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

OP Units for each Preferred Unit (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.312336

'

'

Number of real estate properties

'

'

175

8

167

128

8

39

1

4

3

'

'

'

'

'

'

Net Rentable Area

'

'

45,800,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of vehicles in structured parking

45,971

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Area of parking structures (in square feet)

15,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Area of undeveloped land parcels owned (in acres)

502.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred Stock Dividend Payable Per Share

'

'

'

'

'

'

'

'

'

'

'

$0.25

'

'

'

'

'

Series Four Preferred Units Annual Dividend Payable Rate

'

'

'

'

'

'

'

'

'

'

'

2.00%

'

'

'

'

'

Basis_Of_Presentation_And_Summ3

Basis Of Presentation And Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2013
Accounting Policies [Abstract]	'
Reclassification between general and administrative expense and real estate operating expense	$1.90

Basis_Of_Presentation_And_Summ4

Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]	'	'
Mortgage notes payable	$4,430,110,000	$4,449,734,000
Mezzanine notes payable	310,735,000	311,040,000
Unsecured senior notes	5,836,290,000	5,835,854,000
Unsecured exchangeable senior notes	0	744,880,000
Carrying Amount [Member]	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'
Mortgage notes payable	4,430,110,000	4,449,734,000
Mezzanine notes payable	310,735,000	311,040,000
Unsecured senior notes	5,836,290,000	5,835,854,000
Unsecured exchangeable senior notes	0	744,880,000	[1]
Total	10,577,135,000	11,341,508,000
Estimated Fair Value [Member]	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'
Mortgage notes payable	4,577,435,000	4,545,283,000
Mezzanine notes payable	310,764,000	311,064,000
Unsecured senior notes	6,145,060,000	6,050,517,000
Unsecured exchangeable senior notes	0	750,266,000
Total	11,033,259,000	11,657,130,000
ASC 470-20 Adjustment [Member]	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'
Impact of accounting pronouncement	'	$2,400,000
[1]	Includes the net adjustment for the equity component allocation totaling approximately $2.4 million at DecemberB 31, 2013.

Real_Estate_Activity_During_th2

Real Estate Activity During the Three Months Ended March 31, 2014 (Narrative) (Details) (The Avant at Reston Town Center Residential [Member])	Feb. 10, 2014
	sqft
	apartments
The Avant at Reston Town Center Residential [Member]	'
Real Estate Properties [Line Items]	'
Number of apartment units	359
Net Rentable Area	355,000

Real_Estate_Activity_During_th3

Real Estate Activity During the Three Months Ended March 31, 2014 (Summary Of The Discontinued Operations Related to Montvale Center, 303 Almaden Blvd, 1301 New York Avenue, One Preserve Parkway, and 10 & 20 Burlington Mall Road) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total revenue	$574,694	$477,826
Expenses	'	'
Depreciation and amortization	152,245	117,409
Total expenses	395,772	343,875
Operating income	178,922	133,951
Other expense	'	'
Interest expense	113,554	100,433
Income from discontinued operations	'	20,378
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties LImited Partnership	0	20,736
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	0	-2,852
Montvale Center, 303 Almaden Blvd, 1301 New York Avenue, One Preserve Parkway and 10 & 20 Burlington Mall Road [Member]	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'
Total revenue	'	7,035
Expenses	'	'
Operating	'	2,443
Depreciation and amortization	'	1,738
Total expenses	'	4,181
Operating income	'	2,854
Other expense	'	'
Interest expense	'	360
Income from discontinued operations	'	2,494
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties LImited Partnership	'	20,736
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	'	($2,852)

Investments_in_Unconsolidated_2

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) (USD $)

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

In Thousands, unless otherwise specified

Square 407 Limited Partnership [Member]

The Metropolitan Square Associates LLC [Member]

BP/CRF 901 New York Avenue LLC [Member]

WP Project Developer LLC [Member]

Boston Properties Office Value-Added Fund, L.P. [Member]

Annapolis Junction NFM, LLC [Member]

2 GCT Venture LLC [Member]

540 Madison Venture LLC [Member]

125 West 55th Street Venture LLC [Member]

500 North Capitol LLC [Member]

Entity Owning Land And Infrastructure Of Project [Member]

Buildings

Land_Parcels

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Properties

'

'

'MarketB SquareB North

'Metropolitan Square

'901B NewB YorkB Avenue

[1]

'Wisconsin Place Land and Infrastructure

[2]

'N/A

[3]

'Annapolis Junction

[4]

'N/A

[5]

'540 Madison Avenue

'N/A

[6]

'500 North Capitol Street, NW

'

Equity Method Investment, Ownership Percentage

'

'

50.00%

51.00%

25.00%

[1]

33.30%

[2]

39.50%

[3]

50.00%

[4]

60.00%

[5]

60.00%

60.00%

[6]

30.00%

33.30%

Carrying value of the Company's investments in unconsolidated joint ventures

$127,356

$126,084

($9,758)

$6,236

($2,509)

$46,944

($30)

$17,528

($91)

$69,002

$944

($910)

'

Number of real estate properties

'

'

'

'

'

'

'

2

'

'

'

'

'

Number of buildings under construction

'

'

'

'

'

'

'

1

'

'

'

'

'

Parcels of undeveloped land

'

'

'

'

'

'

'

2

'

'

'

'

'

[1]

The Companybs economic ownership can increase based on the achievement of certain return thresholds.

[2]

The Companybs wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.

[3]

The Company acquired Mountain View Research Park and Mountain View Technology Park from the Value-Added Fund on April 10, 2013.

[4]

Comprised of two buildings, one building under construction and two undeveloped land parcels (See also Note 12).

[5]

Two Grand Central Tower was sold on OctoberB 25, 2011.

[6]

125 West 55th Street was sold on MayB 30, 2013.

Investments_in_Unconsolidated_3

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'		'
Real estate and development in process, net	$15,497,138		$15,451,531
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY	'		'
Mortgage and notes payable	4,430,110		4,449,734
Other liabilities	556,772		578,969
Total liabilities and capital	18,615,930		19,796,588
Carrying value of the Company's investments in unconsolidated joint ventures	127,356		126,084
Unconsolidated Joint Ventures [Member]	'		'
ASSETS	'		'
Real estate and development in process, net	921,524		924,297
Other assets	158,375		163,149
Total assets	1,079,899		1,087,446
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY	'		'
Mortgage and notes payable	748,700		749,732
Other liabilities	19,593		28,830
Members'/Partners' equity	311,606		308,884
Total liabilities and capital	1,079,899		1,087,446
Company's share of equity	155,807		154,726
Basis differentials	-28,451	[1]	-28,642	[1]
Carrying value of the Company's investments in unconsolidated joint ventures	$127,356		$126,084
[1]	unt represents the aggregate difference between the Companybs historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from impairment of investments and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level.

Investments_in_Unconsolidated_4

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Schedule of Equity Method Investments [Line Items]	'		'
Total revenue	$574,694,000		$477,826,000
Expenses	'		'
Depreciation and amortization	152,245,000		117,409,000
Total expenses	395,772,000		343,875,000
Operating income	178,922,000		133,951,000
Other expense	'		'
Interest expense	113,554,000		100,433,000
Income from continuing operations	69,781,000		44,445,000
Net income	69,781,000		64,823,000
Income from unconsolidated joint ventures	2,816,000		8,721,000
Unconsolidated Joint Ventures [Member]	'		'
Schedule of Equity Method Investments [Line Items]	'		'
Total revenue	38,034,000	[1]	135,650,000	[1]
Expenses	'		'
Operating	15,464,000		42,366,000
Depreciation and amortization	9,092,000		39,277,000
Total expenses	24,556,000		81,643,000
Operating income	13,478,000		54,007,000
Other expense	'		'
Interest expense	-8,012,000		-56,234,000
Net income	5,466,000		-2,227,000
Company's share of net income (loss)	2,625,000		-1,858,000
Basis differential	191,000		444,000
Elimination of inter-entity interest on partner loan	0		10,135,000
Income from unconsolidated joint ventures	2,816,000		8,721,000
Straight Line Rent Adjustments	-600,000		-4,000,000
Below market rent adjustments, net	$100,000		$20,400,000
[1]	udes straight-line rent adjustments of $0.6 million and $4.0 million for the three months ended March 31, 2014 and 2013, respectively. Includes net below-market rent adjustments of $0.1 million and $20.4 million for the three months ended March 31, 2014 and 2013, respectively.

Unsecured_Exchangeable_Senior_1

Unsecured Exchangeable Senior Notes Unsecured exchangeable Senior Notes (Narrative) (details) (3.625% exchangeable senior notes [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 18, 2014
3.625% exchangeable senior notes [Member]	'
Debt Instrument [Line Items]	'
Coupon/Stated Rate (percent)	3.63%
Redemption of unsecured senior notes	$747.50

Commitments_And_Contingencies_

Commitments And Contingencies (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2009	Jan. 10, 2014
Commitments And Contingencies [Line Items]	'	'	'
Letter of credit and performance obligations	13,200,000	'	'
Property insurance program per occurrence limits	1,000,000,000	'	'
Per occurrence limit for NBCR Coverage	1,000,000,000	'	'
Value of program trigger	100,000,000	'	'
Coinsurance of program trigger (percent)	15.00%	'	'
Deductible in insurance as a percentage of the value of the affected property, San Francisco (percent)	5.00%	'	'
Per occurrence limit of the earthquake insurance which covers San Francisco region	120,000,000	'	'
Annual aggregate limit of the earthquake insurance which covers San Francisco region	120,000,000	'	'
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco	20,000,000	'	'
Earthquake Coverage Included In Builders Risk Policy For 535 Mission	15,000,000	'	'
Earthquake Coverage Included In Builders Risk Policy For Below Grade improvements for Transbay Tower	15,000,000	'	'
Operating partnership guarantee to cover liabilities of IXP	20,000,000	'	'
767 Venture, LLC [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Maximum funding obligation	11,700,000	'	'
Property insurance program per occurrence limits	1,625,000,000	'	'
Coverage for acts of Terrorism certified under TRIA in excess of amount provided by NYIXP, LLC, as a direct insurer	1,375,000,000	'	'
Coverage for acts of terrorism certified under TRIA in excess	250,000,000	'	'
John Hancock Tower [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Guarantee Obligation Related To Tenant Re-Leasing Costs	21,400,000	'	'
Debt Instrument, Maturity Date	6-Jan-17	'	'
601 Lexington Avenue [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	250,000,000	'	'
Lehman [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Bankruptcy claim, amount filed by general creditor	'	45,300,000	'
Bankruptcy claim amount allowed by court to creditor	'	'	$45,200,000
Bankruptcy claim, denominator used to evaluate claim price amount	1	'	'
Lehman [Member] | Minimum [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Bankruptcy claim, price on the private market	0.42	'	'
Lehman [Member] | Maximum [Member]	'	'	'
Commitments And Contingencies [Line Items]	'	'	'
Bankruptcy claim, price on the private market	0.45	'	'

Noncontrolling_Interests_Narra

Noncontrolling Interests (Narrative) (Details)	Mar. 31, 2014
Noncontrolling Interests [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
Operating Partnership (OP) Units (in shares)	15,583,853
Long-Term Incentive Plan (LTIP) Units (in shares)	1,554,353
Series Two Preferred Units (in shares)	666,116
Convertible Operating Partnership (OP) Units (in shares)	874,168
Series Four Preferred Units (in shares)	360,126
OPP Units Two Thousand And Twelve [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
Outperformance awards in LTIP Units (in shares)	394,590
MYLTIP [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
2013 MYLTIP	314,974
MYLTIP Two thousand fourteen [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
Two thousand fourteen MYLTIP	483,555

Noncontrolling_Interests_Redee

Noncontrolling Interests (Redeemable Preferred Units) (Narrative) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Feb. 18, 2014	Aug. 29, 2013
			D
Noncontrolling Interests [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Series Two Preferred Units (in shares)	666,116	'	'
Series Two Preferred Units On Converted Basis	874,168	'	'
Series Four Preferred Units (in shares)	360,126	'	'
Op Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Closing price of common stock (in dollars per share)	$114.53	'	'
Series Two Preferred Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
OP Units for each Preferred Unit (in shares)	1.312336	'	'
Preferred Units Liquidation Preference	$50	'	'
Series Two Preferred Units [Member] | Noncontrolling Interests [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Series Two Preferred Units (in shares)	666,116	'	'
Liquidation preference percentage	6.00%	'	'
Operating Units liquidation preference (in dollars per share)	$38.10	'	'
OP Units for each Preferred Unit (in shares)	1.312336	'	'
Series Two Preferred Units On Converted Basis	874,168	'	'
Distributions to Series Two Preferred Units (in dollars per share)	'	$0.85	'
Preferred Units Liquidation Preference	$50	'	'
series four preferred units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Series Four Preferred Units Annual Dividend Payable Rate	2.00%	'	'
Preferred Units Liquidation Preference	$50	'	'
series four preferred units [Member] | Noncontrolling Interests [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Distributions to Series Two Preferred Units (in dollars per share)	'	$0.25	'
Series Four Preferred Units (in shares)	360,126	'	'
Series Four Preferred Units Annual Dividend Payable Rate	2.00%	'	'
Preferred Units Liquidation Preference	$50	'	'
First opportunity to redeem Series Four Preferred Units (in days)	'	'	30
OP Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Value of Series Two Preferred Units assuming conversion	$100.10	'	'

Noncontrolling_Interests_Commo

Noncontrolling Interests (Common Units) (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended
In Billions, except Share data, unless otherwise specified	Jan. 29, 2014	Mar. 31, 2014	Mar. 18, 2014
OP Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
OP Units for redemption (in shares)	'	18,528	'
Redemption of OP units issued on conversion of LTIP Units (in shares)	'	17,191	'
OPP and MYLTIP Units distribution as percentage of OP Unit distribution prior to measurement date	'	10.00%	'
Distributions made to OP and LTIP units per unit (in dollars per share)	$0.65	'	'
Distribution paid to outperformance awards, OPP Units (in dollars per share)	$0.07	'	'
Distribution declared to OP and LTIP units by Boston Properties, Inc. (in dollars per share)	'	'	$0.65
Distribution declared to outperformance awards OPP Units by Boston Properties, Inc. (in dollars per share)	'	'	$0.07
Common units of operating partnership if converted value	'	$2	'
Closing price of common stock (in dollars per share)	'	$114.53	'
OPP Units Two Thousand And Twelve [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Outperformance awards in LTIP Units (in shares)	'	394,590	'
MYLTIP [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
2013 MYLTIP	'	314,974	'
MYLTIP Two thousand fourteen [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Two thousand fourteen MYLTIP	'	483,555	'
Quarter 4 2013 [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Dividend shareholder of record date	'	31-Dec-13	'
Dividend payable date	'	29-Jan-14	'
Quarter 4 2013 [Member] | OP Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Dividend payable date	'	29-Jan-14	'
Holders of record date	'	31-Dec-13	'
Quarter 1 2014 [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Dividend shareholder of record date	'	31-Mar-14	'
Dividends declared date	'	18-Mar-14	'
Dividend payable date	'	30-Apr-14	'
Quarter 1 2014 [Member] | OP Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Dividends declared date	'	18-Mar-14	'
Dividend payable date	'	30-Apr-14	'
Holders of record date	'	31-Mar-14	'
special dividend [Member] | OP Units [Member]	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'
Distributions made to OP and LTIP units per unit (in dollars per share)	$2.25	'	'

Noncontrolling_Interests_Prope

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Feb. 26, 2013	Feb. 07, 2013	Apr. 10, 2014	31-May-13	Oct. 09, 2013	31-May-13
			Salesforece Tower (formerly Transbay Tower) [Member]	Salesforece Tower (formerly Transbay Tower) [Member]	Salesforece Tower (formerly Transbay Tower) [Member]	767 Fifth Avenue (The GM Building) [Member]	Time Square Tower [Member]	767 Fifth Avenue (The GM Building) [Member]
					sqft		sqft	partners
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'
Difference between net cash proceeds received and noncontrolling interest recognized	'	'	'	'	'	'	$429,600,000	'
Partners Joint Venture Ownership Percentage	'	'	5.00%	50.00%	'	40.00%	'	'
Number of Joint Venture Partners	'	'	'	'	'	'	'	2
Ownership Percentage	'	'	95.00%	'	'	'	'	'
maximum percentage of construction costs to allow partner to have a loan	'	'	50.00%	'	'	'	'	'
Portion of total costs partner can require the company to fund	'	'	2.50%	'	'	'	'	'
portion of partners equity that can be funded by the company	'	'	50.00%	'	'	'	'	'
Portion allocation to noncontrolling interest based on carrying value of the total equity of the property prior to the sale	'	'	'	'	'	'	243,500,000	'
Noncontrolling interest recorded upon consolidation	'	'	'	'	'	480,900,000	'	'
ownership interest sold (percent)	'	'	'	'	'	'	45.00%	'
Net Contractual Sales Price	'	'	'	'	'	'	684,000,000	'
Proceeds from sale of an interest in a real estate asset	'	'	'	'	'	'	673,100,000	'
Net Rentable Area	'	'	'	'	1,400,000	'	1,246,000	'
Noncontrolling interests in property partnerships	$725,093,000	$726,132,000	'	'	'	'	'	'

Noncontrolling_Interests_Redee1

Noncontrolling Interests (Redeemable Preferred Units) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Activity of noncontrolling interests	'	'
Net income	$3,208	$1,326
Redeemable Preferred Units [Member]	'	'
Activity of noncontrolling interests	'	'
Beginning Balance	105,746	199,378
Net income	619	1,180
Distributions	-619	-1,180
Reallocation of partnership interest	12,378	-6,208
Ending Balance	$118,124	$193,170

Noncontrolling_Interests_Nonco

Noncontrolling Interests (Noncontrolling Interests-Redeemable Common Units) (Details) (Noncontrolling Interests [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Noncontrolling Interests [Member]	'	'
Activity of noncontrolling interests	'	'
Beginning Balance	$1,710,218	$1,836,522
Contributions	23,379	22,403
Net income	6,160	6,177
Distributions	-11,218	-11,446
Conversion of redeemable partnership units	-627	-272
Unearned compensation	-14,619	-5,859
Accumulated other comprehensive loss	62	64
Adjustments to reflect redeemable partnership units at redemption value	249,484	-78,896
Ending Balance	$1,962,839	$1,768,693

Noncontrolling_Interests_Nonco1

Noncontrolling Interests (Noncontrolling Interests-Property Partnerships) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Activity of noncontrolling interests	'	'
Beginning balance	$726,132	'
Capital contributions	468	5,875
Net Income (loss)	4,354	2,574
Ending balance	725,093	'
Property Partnerships [Member]	'	'
Activity of noncontrolling interests	'	'
Beginning balance	726,132	-1,964
Capital contributions	468	10,421
Net Income (loss)	2,586	566
Distributions	-4,093	-750
Ending balance	$725,093	$8,273

Noncontrolling_Interests_Redee2

Noncontrolling Interests Redeemable Interest in Property Partnerships (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Redeemable Interest in Property Partnership [Abstract]	'	'
Beginning Balance	$99,609	$97,558
Net loss	-106	-525
Distributions	-1,050	-1,350
Adjustment to reflect redeemable interest at redemption value	1,874	2,533
Ending Balance	$100,327	$98,216

Noncontrolling_Interests_Nonco2

Noncontrolling Interests Noncontrolling interest - Reddemable interest in Property Partnerships (Details) (Fountain Square [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 04, 2012
Fountain Square [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
Aggregate purchase price	$385
Indebtedness assumed	211.3
Ownership Percentage	50.00%
Payments to Acquire Businesses, Gross	87
Noncontrolling Interest, Ownership Percentage by Parent	50.00%
Future Fixed Price to Acquire Remaining Portion of Joint venture	$102
Fixed Price Option Expiration Date	31-Jan-16

Partners_Capital_Details

Partners' Capital (Details) (USD $)

0 Months Ended

3 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

3 Months Ended

Jan. 29, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 18, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Feb. 18, 2014

Mar. 31, 2014

Mar. 27, 2018

Mar. 18, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 27, 2018

Mar. 31, 2014

ATM Program [Member]

Quarter 4 2013 [Member]

Quarter 1 2014 [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Depository shares of Series B Cumulative Redeemable Preferred [Member]

Depository shares of Series B Cumulative Redeemable Preferred [Member]

Quarter 1 2014 [Member]

Quarter 2 2014 [Member]

Class of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

General partnership units (in units)

'

1,701,555

'

'

1,700,222

'

'

'

'

'

'

'

'

'

'

'

'

Limited partnership units (in units)

'

151,315,756

'

'

151,282,879

'

'

'

'

'

'

'

'

'

'

'

'

At the market stock offering program, aggregate value of common stock

'

'

'

'

'

$600,000,000

'

'

'

'

'

'

'

'

'

'

'

At the market stock offering program remaining amount available for issuance

'

'

'

'

'

305,300,000

'

'

'

'

'

'

'

'

'

'

'

Shares of its Common Stock in connection with the redemption of an equal number of OP Units (in shares)

'

18,528

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividend payable date

'

'

'

'

'

'

29-Jan-14

30-Apr-14

'

'

'

'

'

18-Feb-14

15-May-14

'

'

Dividend paid on common stock (in dollars per share)

$2.90

'

'

'

'

'

'

'

$32.81

'

'

'

'

'

'

'

'

Dividend shareholder of record date

'

'

'

'

'

'

31-Dec-13

31-Mar-14

'

'

'

'

'

'

5-May-14

'

'

Dividends payable, date declared

'

'

'

'

'

'

'

18-Mar-14

'

'

'

'

'

'

18-Mar-14

'

'

Dividends payable (in dollars per share)

'

'

'

$0.65

'

'

'

'

'

'

'

$32.81

'

'

'

'

'

Series B, Units Outstanding

'

'

'

'

'

'

'

'

'

80,000

'

'

80,000

'

'

'

8,000,000

Series B, Liquidation Preference Per Unit

'

'

'

'

'

'

'

'

'

$2,500

$2,500

'

$2,500

'

'

$25

$25

Proceeds from Issuance of Series B Preferred Stock

'

$0

$194,371,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ratio of depository shares to shares of Series B Preferred Stock

'

'

'

'

'

'

'

'

'

0.01

'

'

'

'

'

'

'

Series B, Dividend Rate, Percentage

'

'

'

'

'

'

'

'

'

5.25%

'

'

'

'

'

'

'

Earnings_Per_Common_Unit_Detai

Earnings Per Common Unit (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Income (Loss) from Continuing Operations Attributable to Parent	'	$40,545
Redeemable common units (in shares)	16,811,000	17,104,000
Basic Earnings:	'	'
Net income attributable to Boston Properties Limited Partnership, Units (Denominator) (in shares)	169,841,000	168,750,000
Discontinued operations attributable to Boston Properties Limited Partnership, Income (Numerator)	'	20,378
Discontinued operations attributable to Boston Properties Limited Partnership, Per Unit Amount (in dollars per share)	$0	$0.12
Net income attributable to Boston Properties Limited Partnership	62,219	60,923
Net income (in dollars per share)	$0.37	$0.36
Effect of Dilutive Securities:	'	'
Stock Based Compensation and Exchangeable Senior Notes, Income (Numerator)	0	0
Stock Based Compensation and Exchangeable Senior Notes, Units (Denominator) (in shares)	139,000	306,000
Stock Based Compensation and Exchangeable Senior Notes, Per Unit Amount (in dollars per share)	$0	$0
Diluted Earnings:	'	'
Diluted Earnings: Net income attributable to Boston Properties Limited Partnership	$62,219	$60,923
Diluted Earnings: Net income, Units (Denominator) (in shares)	169,980,000	169,056,000
Diluted Earnings: Net income, Per Unit Amount (in dollars per share)	$0.37	$0.36

Stock_Option_and_Incentive_Pla1

Stock Option and Incentive Plan (Restricted Stock) (Narrative) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
stock based compensation expense	$9.90	$25.50
Restricted Stock [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
Shares issued (in shares)	21,455	'
Employee and director payment per share (in dollars per share)	$0.01	'
Value of shares of common stock	2.3	'
Employee's weighted average cost per share (in dollars per share)	$108.09	'
LTIP Units [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
LTIP units issued (in shares)	121,567	'
Expected life assumed to calculate per unit fair value per LTIP unit (in years)	'5 years 8 months 12 days	'
Risk-free rate	1.84%	'
Expected price volatility	27.00%	'
Value of LTIP units issued	12.2	'
Per unit fair value weighted-average (in dollars per share)	$100.16	'
Opp Units Two Thousand And Eleven [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
Accelerated Compensation Expenses Related To two thousand eleven Opp Units	1.2	'
MYLTIP [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
MYLTIP units issued (in shares)	485,459	'
LTIPs And Restricted Stock [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
Vesting annual installments	4	'
Unrecognized compensation expenses	24.9	'
LTIPs and OPP Awards [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
Employee and director payment per share (in dollars per share)	$0.25	'
Unvested 2011, 2012 OPP Units and 2013 MYLTIP Units [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
Unrecognized compensation expenses	20.6	'
Weighted-average period (in years)	'3 years 3 months 18 days	'
Board of Directors Chairman [Member]	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'
stock based compensation expense	'	$16.90

Stock_Option_and_Incentive_Pla2

Stock Option and Incentive Plan Stock option and incentive plan (Narrative) (Details) (USD $)

3 Months Ended

0 Months Ended

3 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Jan. 27, 2014

Mar. 31, 2013

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Vesting 2017 [Member]

MYLTIP vesting two thousand eighteen [Member]

Board of Directors Chairman [Member]

indices

Cohen & Steers Realty Majors Portfolio Index [Member]

NAREIT Office Index adjusted [Member]

Minimum [Member]

Maximum [Member]

Threshold [Member]

Target [Member]

Exceptional [Member]

High [Member]

MYLTIP Two thousand fourteen [Member]

MYLTIP Two thousand fourteen [Member]

tiers

Y

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

stock based compensation expense

$9,900,000

$25,500,000

'

'

'

'

'

'

'

'

'

'

'

$16,900,000

TRS Measurement, Years

'

'

3

'

'

'

'

'

'

'

'

'

'

'

Weighted Percentage of Index Used to Compare to TRS

'

'

'

50.00%

50.00%

'

'

'

'

'

'

'

'

'

Potential Awards Earned

'

'

'

'

'

0

40,200,000

'

'

'

'

'

'

'

Indices Used to Compare TRS

'

'

2

'

'

'

'

'

'

'

'

'

'

'

Number of Tiers

'

'

4

'

'

'

'

'

'

'

'

'

'

'

Amount of Each Tier

'

'

'

'

'

'

'

6,700,000

13,400,000

40,200,000

26,800,000

'

'

'

Percentage of annualized TRS for Reduction of Earned Awards

'

'

0.00%

'

'

'

'

'

'

'

'

'

'

'

Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards

'

'

12.00%

'

'

'

'

'

'

'

'

'

'

'

Vesting Percentage

'

'

'

'

'

'

'

'

'

'

'

50.00%

50.00%

'

Vesting Date

'

'

'

'

'

'

'

'

'

'

'

3-Feb-17

3-Feb-18

'

Distributions Percent Before Measurement Date

'

'

10.00%

'

'

'

'

'

'

'

'

'

'

'

Value of MYLTIP Awards

'

'

$12,700,000

'

'

'

'

'

'

'

'

'

'

'

MYLTIP Value Amortized Into Earnings, Years

'

'

4

'

'

'

'

'

'

'

'

'

'

'

Segment_Information_Schedule_O

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Rental Revenue: Class A Office	$539,906	$445,377
Rental Revenue: Office/Technical	15,697	9,847
Rental Revenue: Residential	5,682	5,578
Rental Revenue: Hotel	8,193	8,291
Rental Revenue Total	569,478	469,093
Total revenue	574,694	477,826
Rental Revenue: % of Grand Totals	100.00%	100.00%
Rental Expenses: Class A Office	198,521	163,503
Rental Expenses: Office/Technical	4,105	2,826
Rental Expenses: Residential	3,762	2,733
Rental Expenses: Hotel	6,797	7,044
Rental Expenses: Total	213,185	176,106
Rental Expenses: % Of Grand Totals	100.00%	100.00%
Operating Income Loss From Reportable Segments	356,293	292,987
Percentage Of Total Net Operating Income	100.00%	100.00%
Boston [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Rental Revenue: Class A Office	170,942	160,824
Rental Revenue: Office/Technical	5,820	5,653
Rental Revenue: Residential	1,163	1,067
Rental Revenue: Hotel	8,193	8,291
Rental Revenue Total	186,118	175,835
Rental Revenue: % of Grand Totals	32.68%	37.48%
Rental Expenses: Class A Office	71,398	65,287
Rental Expenses: Office/Technical	1,689	1,787
Rental Expenses: Residential	448	443
Rental Expenses: Hotel	6,797	7,044
Rental Expenses: Total	80,332	74,561
Rental Expenses: % Of Grand Totals	37.68%	42.35%
Operating Income Loss From Reportable Segments	105,786	101,274
Percentage Of Total Net Operating Income	29.69%	34.57%
New York [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Rental Revenue: Class A Office	217,308	138,523
Rental Revenue: Office/Technical	0	0
Rental Revenue: Residential	0	0
Rental Revenue: Hotel	0	0
Rental Revenue Total	217,308	138,523
Rental Revenue: % of Grand Totals	38.16%	29.53%
Rental Expenses: Class A Office	74,371	49,088
Rental Expenses: Office/Technical	0	0
Rental Expenses: Residential	0	0
Rental Expenses: Hotel	0	0
Rental Expenses: Total	74,371	49,088
Rental Expenses: % Of Grand Totals	34.89%	27.87%
Operating Income Loss From Reportable Segments	142,937	89,435
Percentage Of Total Net Operating Income	40.12%	30.53%
San Francisco [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Rental Revenue: Class A Office	54,608	52,671
Rental Revenue: Office/Technical	6,217	151
Rental Revenue: Residential	0	0
Rental Revenue: Hotel	0	0
Rental Revenue Total	60,825	52,822
Rental Revenue: % of Grand Totals	10.68%	11.26%
Rental Expenses: Class A Office	19,313	18,373
Rental Expenses: Office/Technical	1,214	35
Rental Expenses: Residential	0	0
Rental Expenses: Hotel	0	0
Rental Expenses: Total	20,527	18,408
Rental Expenses: % Of Grand Totals	9.63%	10.45%
Operating Income Loss From Reportable Segments	40,298	34,414
Percentage Of Total Net Operating Income	11.31%	11.75%
Washington, DC [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Rental Revenue: Class A Office	97,048	93,359
Rental Revenue: Office/Technical	3,660	4,043
Rental Revenue: Residential	4,519	4,511
Rental Revenue: Hotel	0	0
Rental Revenue Total	105,227	101,913
Rental Revenue: % of Grand Totals	18.48%	21.73%
Rental Expenses: Class A Office	33,439	30,755
Rental Expenses: Office/Technical	1,202	1,004
Rental Expenses: Residential	3,314	2,290
Rental Expenses: Hotel	0	0
Rental Expenses: Total	37,955	34,049
Rental Expenses: % Of Grand Totals	17.80%	19.33%
Operating Income Loss From Reportable Segments	$67,272	$67,864
Percentage Of Total Net Operating Income	18.88%	23.15%

Segment_Information_Schedule_O1

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership	'	'
Net Operating Income	$178,922	$133,951
Development and management services income	5,216	8,733
Income from unconsolidated joint ventures	2,816	8,721
Interest and other income	1,311	1,471
Gains (Losses) from investments in securities	286	735
Gain on forgiveness of debt from discontinued operations	0	20,736
General and administrative expense	29,905	45,516
Transaction costs	437	443
Depreciation and amortization expense	152,245	117,409
Interest expense	113,554	100,433
Impairment loss	0	4,401
Impairment loss from discontinued operations	0	2,852
Noncontrolling interest in property partnerships	4,354	2,574
Noncontrolling interest-redeemable preferred units	3,208	1,326
Net income attributable to Boston Properties Limited Partnership	62,219	60,923
Intersegment Eliminations [Member]	'	'
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership	'	'
Net Operating Income	356,293	292,987
Development and management services income	5,216	8,733
Income from unconsolidated joint ventures	2,816	8,721
Interest and other income	1,311	1,471
Gains (Losses) from investments in securities	286	735
Income from discontinued operations	0	2,494
Gain on forgiveness of debt from discontinued operations	0	20,736
General and administrative expense	29,905	45,516
Transaction costs	437	443
Depreciation and amortization expense	152,245	117,409
Interest expense	113,554	100,433
Impairment loss	0	4,401
Impairment loss from discontinued operations	0	2,852
Noncontrolling interest in property partnerships	4,354	2,574
Noncontrolling interest-redeemable preferred units	3,208	1,326
Net income attributable to Boston Properties Limited Partnership	$62,219	$60,923

Segment_Information_Segment_In

Segment Information Segment Information (narrative) (Details) (USD $)	3 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2013	Mar. 31, 2013	31-May-13
		Princeton [Member]	San Francisco [Member]	767 Fifth Avenue (The GM Building) [Member]
				partners
Segment Reporting Information [Line Items]	'	'	'	'
Reclassification between general and administrative expense and real estate operating expense	$1.90	$0.40	$1.50	'
Number of Joint Venture Partners	'	'	'	2

Subsequent_Events_Subsequent_E

Subsequent Events Subsequent Events (Details) (USD $)	3 Months Ended		0 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Apr. 10, 2014	Feb. 26, 2013	Feb. 07, 2013	Apr. 10, 2014	Apr. 30, 2014	Apr. 10, 2014	Apr. 10, 2014	Apr. 30, 2014
			Salesforece Tower (formerly Transbay Tower) [Member]	Salesforece Tower (formerly Transbay Tower) [Member]	Salesforece Tower (formerly Transbay Tower) [Member]	501 K Street [Member]	Annapolis Junction Building Eight [Member]	Company [Member]	Company [Member]	Company [Member]
			sqft			sqft	sqft	Salesforece Tower (formerly Transbay Tower) [Member]	501 K Street [Member]	Annapolis Junction Building Eight [Member]
			floor
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'	'
Capital contributions to unconsolidated joint ventures	$0	$113	'	'	'	$39,000	$5,400	'	'	'
Ownership Percentage	'	'	'	95.00%	'	'	'	95.00%	'	'
Square Footage Of Signed Lease	'	'	714,000	'	'	'	'	'	'	'
Net Rentable Area	'	'	1,400,000	'	'	520,000	125,000	'	'	'
Partners Joint Venture Ownership Percentage	'	'	'	5.00%	50.00%	50.00%	'	'	'	'
Equity Method Investment, Ownership Percentage	'	'	'	'	'	'	'	'	50.00%	50.00%
Number of floors of real estate	'	'	61	'	'	'	'	'	'	'