Boston Properties LTD Partnership 10-Q 8 Aug 14 2014 Q2 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	6 Months Ended
	Jun. 30, 2014	Aug. 04, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
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 $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Real estate, at cost	$17,250,231	$16,727,886
Construction in progress	1,309,781	1,523,179
Land held for future development	273,587	297,376
Less: accumulated depreciation	-3,300,262	-3,096,910
Total real estate	15,533,337	15,451,531
Cash and cash equivalents	1,036,576	2,365,137
Cash held in escrows	59,248	57,201
Investments in securities	18,927	16,641
Tenant and other receivables (net of allowance for doubtful accounts of $1,496 and $1,636, respectively)	51,348	59,464
Accrued rental income (net of allowance of $6,756 and $3,636, respectively)	673,587	651,603
Deferred charges, net	853,924	884,450
Prepaid expenses and other assets	133,035	184,477
Investments in unconsolidated joint ventures	176,939	126,084
Total assets	18,536,921	19,796,588
Liabilities:	'	'
Mortgage notes payable	4,411,453	4,449,734
Unsecured senior notes (net of discount of $13,271 and $14,146 respectively)	5,836,729	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	310,427	311,040
Outside member's notes payable	180,000	180,000
Accounts payable and accrued expenses	216,080	202,470
Distributions payable	112,420	497,242
Accrued interest payable	156,024	167,523
Other liabilities	539,716	578,969
Total liabilities	11,762,849	12,967,712
Commitments and contingencies	0	0
Noncontrolling interests:	'	'
Redeemable interest in property partnerships	103,778	99,609
Redeemable partnership units— 0 and 666,116 series two preferred units outstanding (0 and 874,168 common units at redemption value, if converted) at June 30, 2014 and December 31, 2013	0	87,740
Redeemable partnership units - 360,126 series four preferred units outstanding at redemption value at June 30, 2014 and December 31, 2013	18,006	18,006
Redeemable partnership units—16,458,014 and 15,583,370 common units and 1,511,796 and 1,455,761 long term incentive units outstanding at redemption value at June 30, 2014 and December 31, 2013, respectively	2,123,672	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 June 30, 2014 and December 31,2013	193,623	193,623
Boston Properties Limited Partnership partners’ capital—1,710,624 and 1,700,222 general partner units and 151,381,950 and 151,282,879 limited partner units outstanding at June 30, 2014 and December 31, 2013, respectively	3,613,897	3,993,548
Noncontrolling interests in property partnerships	721,096	726,132
Total capital	4,528,616	4,913,303
Total liabilities and capital	$18,536,921	$19,796,588

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Tenant and other receivables, allowance for doubtful accounts	$1,496	$1,636
Accrued rental income, allowance	6,756	3,636
Unsecured senior notes, discount	13,271	14,146
Unsecured exchangeable senior notes, discount	$0	$182
Redeemable partnership units, series two preferred units outstanding (in units)	0	666,116
Redeemable partnership units, common units at redemption value, if converted (in units)	0	874,168
Redeemable partnership units, series four preferred units outstanding (in units)	360,126	360,126
Redeemable partnership units, common units (in units)	16,458,014	15,583,370
Redeemable partnership units, long term incentive units outstanding at redemption value (in units)	1,511,796	1,455,761
General Partners' Capital Account, Units Outstanding (in units)	1,710,624	1,700,222
Limited Partners' Capital Account, Units Outstanding (in units)	151,381,950	151,282,879
Series B Cumulative Redeemable Preferred Stock [Member]	'	'
Series B Dividend Rate Percentage	5.25%	5.25%
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		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue	'	'	'	'
Base rent	$463,239	$399,192	$918,257	$772,238
Recoveries from tenants	81,382	68,321	163,316	132,640
Parking and other	26,300	23,547	50,633	46,984
Total rental revenue	570,921	491,060	1,132,206	951,862
Hotel revenue	12,367	11,118	20,560	19,409
Development and management services	6,506	7,855	11,722	16,588
Total revenue	589,794	510,033	1,164,488	987,859
Expenses	'	'	'	'
Rental	202,646	176,018	409,034	345,080
Hotel	7,315	7,335	14,112	14,379
General and administrative	23,271	24,316	53,176	69,832
Transaction costs	661	535	1,098	978
Impairment loss	0	0	0	4,401
Depreciation and amortization	152,602	131,506	304,847	248,915
Total expenses	386,495	339,710	782,267	683,585
Operating income	203,299	170,323	382,221	304,274
Other income (expense)	'	'	'	'
Income from unconsolidated joint ventures	2,834	48,783	5,650	57,504
Gain on consolidation of joint ventures	0	387,801	0	387,801
Interest and other income	2,109	1,296	3,420	2,767
Gains (Losses) from investments in securities	662	181	948	916
Gains from early extinguishments of debt	0	152	0	152
Interest expense	-110,977	-103,140	-224,531	-203,573
Income (loss) from continuing operations	97,927	505,396	167,708	549,841
Discontinued operations	'	'	'	'
Income from discontinued operations	0	3,315	0	5,809
Gain on forgiveness of debt from discontinued operations	0	0	0	20,736
Impairment loss from discontinued operations	0	0	0	-2,852
Net income	97,927	508,711	167,708	573,534
Net income attributable to noncontrolling interests	'	'	'	'
Noncontrolling interest in property partnerships	-7,553	219	-11,907	-2,355
Noncontrolling interest-redeemable preferred units	-2,938	-3,741	-6,146	-5,067
Net income attributable to Boston Properties Limited Partnership	$87,436	$505,189	$149,655	$566,112
Basic earnings per common unit attributable to Boston Properties Limited Partnership	'	'	'	'
Income from continuing operations (in dollars per share)	$0.51	$2.95	$0.88	$3.19
Discontinued operations (in dollars per share)	$0	$0.02	$0	$0.14
Net income (in dollars per share)	$0.51	$2.97	$0.88	$3.33
Weighted average number of common units outstanding (in shares)	170,382	168,933	170,113	168,842
Diluted earnings per common unit attributable to Boston Properties Limited Partnership	'	'	'	'
Income from continuing operations (in dollars per share)	$0.51	$2.94	$0.88	$3.18
Discontinued operations (in dollars per share)	$0	$0.02	$0	$0.14
Diluted Earnings: Net income, Per Unit Amount (in dollars per share)	$0.51	$2.96	$0.88	$3.32
Weighted average number of common and common equivalent units outstanding (in shares)	170,542	169,485	170,262	169,271

Consolidated_Statements_Of_Com

Consolidated Statements Of Comprehensive Income (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Statement of Comprehensive Income [Abstract]	'		'		'		'
Net income	$97,927		$508,711		$167,708		$573,534
Other comprehensive income:	'		'		'		'
Amortization of interest rate contracts	624	[1]	627	[1]	1,253	[1]	1,255	[1]
Other Comprehensive Income	624		627		1,253		1,255
Comprehensive income	98,551		509,338		168,961		574,789
Comprehensive income attributable to noncontrolling interests	-10,491		-3,522		-18,053		-7,422
Comprehensive income attributable to Boston Properties Limited Partnership	$88,060		$505,816		$150,908		$567,367
[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 $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Increase (Decrease) in Partners' Capital [Roll Forward]	'	'
Beginning Balance	$4,187,171	$3,330,605
Contributions	3,524	196,919
Net income allocable to general and limited partner units	139,852	511,699
Distributions	-204,178	-200,380
Accumulated other comprehensive loss	1,127	1,128
Unearned compensation	376	2,654
Conversion of redeemable partnership units	2,241	10,309
Adjustment to reflect redeemable partnership units at redemption value	-322,593	67,162
Ending Balance	$3,807,520	$3,920,096

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:	'	'
Net income	$167,708	$573,534
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	304,847	251,801
Non-cash compensation expense	16,899	32,464
Impairment loss	0	4,401
Income from unconsolidated joint ventures	-5,650	-57,504
Gains on Consolidation of Joint Ventures	0	-387,801
Distributions of net cash flow from operations of unconsolidated joint ventures	2,205	25,689
Gains from investments in securities	-948	-916
Non-cash portion of interest expense	-18,171	20,120
Settlement of accreted debt discount on repurchases of unsecured exchangeable senior notes	-92,979	-56,532
Gains from early extinguishments of debt	0	-264
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	-2,047	2,687
Tenant and other receivables, net	8,116	-7,018
Accrued rental income, net	-21,984	-29,127
Prepaid expenses and other assets	51,442	17,708
Accounts payable and accrued expenses	-4,704	1,399
Accrued interest payable	-11,499	2,022
Other liabilities	-39,253	-20,086
Tenant leasing costs	-44,989	-19,855
Total adjustments	141,285	-238,696
Net cash provided by operating activities	308,993	334,838
Cash flows from investing activities:	'	'
Acquisitions of real estate	0	-522,900
Construction in progress	-206,603	-181,056
Building and other capital improvements	-37,285	-23,681
Tenant improvements	-53,935	-55,988
Proceeds from sales of real estate	0	39,320
Cash recorded upon consolidation	0	79,468
Repayments of notes receivable, net	0	12,491
Capital contributions to unconsolidated joint ventures	-47,767	0
Capital distributions from unconsolidated joint ventures	357	201,182
Investments in securities, net	-1,338	-1,138
Net cash used in investing activities	-346,571	-452,302
Cash flows from financing activities:	'	'
Repayments of mortgage notes payable	-12,207	-79,865
Proceeds from unsecured senior notes	0	1,194,753
Redemption/Repurchase of unsecured exchangeable senior notes	-654,521	-393,468
Deferred financing costs	-31	-8,546
Net proceeds from preferred units issuance	0	193,920
Net proceeds from equity transactions	1,162	-694
Distributions	-612,612	-223,451
Proceeds from noncontrolling interest in property partnership	1,675	6,018
Distributions to noncontrolling interest in property partnerships	-14,449	-4,450
Net cash provided by (used in) financing activities	-1,290,983	684,217
Net decrease)in cash and cash equivalents	-1,328,561	566,753
Cash and cash equivalents, beginning of period	2,365,137	1,041,978
Cash and cash equivalents, end of period	1,036,576	1,608,731
Supplemental disclosures:	'	'
Cash paid for interest	379,766	271,177
Interest capitalized	32,586	32,854
Non-cash investing and financing activities:	'	'
Additions to real estate included in accounts payable and accrued expenses	4,831	4,746
Real estate and related intangibles recorded upon consolidation	0	3,356,000
Debt recorded upon consolidation	0	2,056,000
Working capital recorded upon consolidation	0	170,748
Noncontrolling interest recorded upon consolidation	0	483,488
Investment in unconsolidated joint venture eliminated upon consolidation	0	361,808
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	112,420	112,425
Issuance of common stock in connection with the exchange of exchangeable senior notes	0	43,834
Conversions of redeemable partnership units to partners' capital	2,241	10,309
Conversion of redeemable preferred units to common units	33,306	0
Issuance of restricted securities to employees and directors	$27,445	$30,077

Organization

Organization	6 Months Ended
	Jun. 30, 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 June 30, 2014 owned an approximate 89.5% (89.2% at June 30, 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 Notes 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 June 30, 2014, there were two series of Preferred Units outstanding (i.e., Series Four Preferred Units and Series B Preferred Units).
	•	The Series Four Preferred Units are not convertible into or exchangeable for any security 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 Notes 7 and 12).
	•	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 June 30, 2014, the Company owned or had interests in a portfolio of 180 commercial real estate properties (the “Properties”) aggregating approximately 46.6 million net rentable square feet, including thirteen properties under construction totaling approximately 4.8 million net rentable square feet. In addition, the Company has structured parking for approximately 46,145 vehicles containing approximately 15.8 million square feet. At June 30, 2014, the Properties consist of:
	•	171 office properties, including 132 Class A office properties (including twelve properties under construction) and 39 Office/Technical properties;
	•	one hotel;
	•	five retail properties (including one property under construction); and
	•	three residential properties.
	The Company owns or controls undeveloped land parcels totaling approximately 492.1 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	6 Months Ended
	Jun. 30, 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 $2.1 million and $4.0 million for the three and six months ended June 30, 2013, respectively, were previously included in Rental Operating Expenses and are now included in General and Administrative Expenses. In addition, beginning on January 1, 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 June 30, 2014 and December 31, 2013 (in thousands):
		June 30, 2014				December 31, 2013
		Carrying		Estimated		Carrying			Estimated
		Amount		Fair Value		Amount			Fair Value
	Mortgage notes payable	$	4,411,453	$	4,547,761	$	4,449,734		$	4,545,283
	Mezzanine notes payable	310,427		310,457		311,040			311,064
	Unsecured senior notes	5,836,729		6,229,201		5,835,854			6,050,517
	Unsecured exchangeable senior notes	—		—		744,880		-1	750,266
	Total	$	10,558,609	$	11,087,419	$	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.
	Out-of-Period Adjustment
	During the three months ended June 30, 2014, the Company recorded an additional allocation of net income to the noncontrolling interest holder in its Fountain Square consolidated joint venture totaling approximately $2.4 million related to the cumulative non-cash adjustment to the accretion of the changes in the redemption value of the noncontrolling interest. This resulted in the overstatement of Noncontrolling Interests in Property Partnerships by approximately $2.4 million during the three months ended June 30, 2014 and in the understatement of Noncontrolling Interests in Property Partnerships in the aggregate amount of approximately $2.4 million in previous periods. Because this adjustment was not material to the prior periods’ consolidated financial statements and the impact of recording the adjustment in the then-current period was not material to the Company’s consolidated financial statements, the Company recorded the related adjustment during the three months ended June 30, 2014.
	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.
	In May 2014, the FASB issued ASU 2014-09, "Revenue from Contract with Customers (Topic 606)" ("ASU 2014-09"). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying ASU 2014-09, companies will perform a five-step analysis of transactions to determine when and how revenue is recognized. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB's Accounting Standards Codification ("ASC"). ASU 2014-09 is effective for annual reporting periods (including interim periods within that reporting period) beginning after December 15, 2016 and shall be applied using either a full retrospective or modified retrospective approach. Early application is not permitted. The Company is currently assessing the potential impact that the adoption of ASU 2014-09 will have on its consolidated financial statements.
	In June 2014, the FASB issued ASU No. 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period” (“ASU 2014-12”). The amendments in ASU 2014-12 require that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in ASC Topic No. 718, “Compensation - Stock Compensation” (“ASC 718”), as it relates to awards with performance conditions that affect vesting to account for such awards. The amendments in ASU 2014-12 are effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Early adoption is permitted. Entities may apply the amendments in ASU 2014-12 either: (a) prospectively to all awards granted or modified after the effective date; or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company does not expect the adoption of ASU 2014-12 to have a material impact on its consolidated financial statements.

Real_Estate_Activity_During_th

Real Estate Activity During the Six Months Ended June 30, 2014	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Real Estate Activity During The Six Months Ended June 30, 2014	'
	Real Estate Activity During the Six Months Ended June 30, 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.
	On April 1, 2014, the Company commenced construction of its 99 Third Avenue development project totaling approximately 17,000 net rentable square feet of retail space located in Waltham, Massachusetts.
	On April 3, 2014, the Company commenced construction of its 690 Folsom Street development project totaling approximately 26,000 net rentable square feet of office and retail space located in San Francisco, California.
	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 commenced construction of the building.
	On May 20, 2014, the Company commenced construction of its 888 Boylston Street development project totaling approximately 425,000 net rentable square feet of Class A office space located in Boston, Massachusetts.
	On May 20, 2014, the Company commenced construction of its 10 CityPoint development project totaling approximately 245,000 net rentable square feet of Class A office space located in Waltham, Massachusetts.
	Dispositions
	The Company did not have any dispositions during the three and six months ended June 30, 2014. The following table summarizes the income from discontinued operations for the three and six months ended June 30, 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 June 30,		For the six months ended June 30,
		2013		2013
		(in thousands)
	Total revenue	$	6,815	$	13,850
	Expenses
	Operating	2,352		4,795
	Depreciation and amortization	1,148		2,886
	Total expenses	3,500		7,681
	Operating income	3,315		6,169
	Other expense
	Interest expense	—		360
	Income from discontinued operations	$	3,315	$	5,809
	Gain on forgiveness of debt from discontinued operations	$	—	$	20,736
	Impairment loss from discontinued operations	$	—	$	(2,852	)
	On June 11, 2014, the Company entered into a contract for the sale of its Patriots Park properties located in Reston, Virginia for a sale price of $321.0 million, which exceeds the carrying value at June 30, 2014. Patriots Park consists of three Class A office properties aggregating approximately 706,000 net rentable square feet. The sale is subject to government approvals and the satisfaction of customary closing conditions and there can be no assurance that the sale will be consummated on the terms currently contemplated or at all.

Investments_in_Unconsolidated_

Investments in Unconsolidated Joint Ventures	6 Months Ended
	Jun. 30, 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 June 30, 2014:
	Entity		Properties		Nominal %				Carrying Value of Investment
					Ownership
									(in thousands)
	Square 407 Limited Partnership		Market Square North		50	%			$	(9,112	)
	The Metropolitan Square Associates LLC		Metropolitan Square		51	%			6,561
	BP/CRF 901 New York Avenue LLC		901 New York Avenue		25	%	(1)		(1,974		)
	WP Project Developer LLC		Wisconsin Place Land and Infrastructure		33.3	%	(2)		46,455
	Annapolis Junction NFM, LLC		Annapolis Junction		50	%	(3)		23,763
	2 GCT Venture LLC		N/A		60	%	-4		326
	540 Madison Venture LLC		540 Madison Avenue		60	%			69,664
	500 North Capitol LLC		500 North Capitol Street, NW		30	%			(862		)
	501 K Street LLC		501 K Street		50	%	-5		42,118
									$	176,939
	_______________
	-1	The Company’s economic ownership has increased 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 joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels.
	-4	Two Grand Central Tower was sold on October 25, 2011.
	-5	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
	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:
		June 30, 2014				31-Dec-13
		(in thousands)
	ASSETS
	Real estate and development in process, net	$	1,010,834			$	924,297
	Other assets	175,872				163,149
	Total assets	$	1,186,706			$	1,087,446
	LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
	Mortgage and notes payable	$	747,988			$	749,732
	Other liabilities	26,704				28,830
	Members’/Partners’ equity	412,014				308,884
	Total liabilities and members’/partners’ equity	$	1,186,706			$	1,087,446
	Company’s share of equity	$	205,134			$	154,726
	Basis differentials (1)	(28,195		)		(28,642		)
	Carrying value of the Company’s investments in unconsolidated joint ventures	$	176,939			$	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 June 30,								For the six months ended June 30,
		2014				2013				2014		2013
		(in thousands)
	Total revenue (1)	$	38,437			$	99,831			$	76,471	$	235,481
	Expenses
	Operating	15,461				32,497				30,925		74,863
	Depreciation and amortization	9,167				27,141				18,259		66,418
	Total expenses	24,628				59,638				49,184		141,281
	Operating income	13,809				40,193				27,287		94,200
	Other expense
	Interest expense	7,984				40,054				15,996		96,288
	Losses from early extinguishment of debt	—				1,677				—		1,677
	Income (loss) from continuing operations	5,825				(1,538		)		11,291		(3,765		)
	Gain on sale of real estate	—				1,766				—		1,766
	Net income (loss)	$	5,825			$	228			$	11,291	$	(1,999	)
	Company’s share of net income (loss)	$	2,578			$	683			$	5,203	$	(1,175	)
	Gain on sale of real estate	—				43,327				—		43,327
	Basis differential	256				(2,070		)		447		(1,626		)
	Elimination of inter-entity interest on partner loan	—				6,843				—		16,978
	Income from unconsolidated joint ventures	$	2,834			$	48,783			$	5,650	$	57,504
	Gains on consolidation of joint ventures	$	—			$	387,801			$	—	$	387,801
	_______________
	-1	Includes straight-line rent adjustments of $0.3 million and $3.1 million for the three months ended June 30, 2014 and 2013, respectively, and $0.9 million and $7.1 million for the six months ended June 30, 2014 and 2013, respectively. Includes net below-market rent adjustments of $(0.1) million and $13.5 million for the three months ended June 30, 2014 and 2013, respectively, and $0.0 million and $34.0 million for the six months ended June 30, 2014 and 2013, respectively.
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 a 50% interest in the joint venture and the Company contributed cash of approximately $39.0 million for its 50% interest. Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
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 to the joint venture. 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. In addition, on June 23, 2014, the joint venture obtained construction financing collateralized by the development project totaling $26.0 million. The construction financing bears interest at a variable rate equal to LIBOR plus 1.50% per annum and matures on June 23, 2017, with two, one-year extension options, subject to certain conditions.

Unsecured_Exchangeable_Senior_

Unsecured Exchangeable Senior Notes Unsecured Exchangeable Senior Notes	6 Months Ended
	Jun. 30, 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	6 Months Ended
	Jun. 30, 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). Under certain of the Company's joint venture agreements, if certain return thresholds are achieved the partners will be entitled to an additional promoted interest or payments.
	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 June 30, 2014, the maximum funding obligation under the guarantee was approximately $22.4 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 $30.5 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 portions 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 the business of Lehman Brothers allowed the Company’s claim in the amount of $45.2 million. Recently, claims of similar priority were quoted privately within a range of $0.40 to $0.41 per $1.00 of claim. The Company was notified on July 30, 2014 that the bankruptcy court approved the trustee’s motion to make an initial interim distribution to holders of claims as of July 15, 2014. The Company will continue to evaluate whether to attempt to sell the claim or wait until the trustee distributes proceeds from the Lehman estate. Given the inherent uncertainties in bankruptcy proceedings, there can be no assurance as to the timing or amount of potential proceeds, if any, that the Company may ultimately realize on the claim, whether by sale to a third party or by one or more distributions from the trustee. Accordingly, the Company has not recorded any estimated recoveries associated with this gain contingency within its consolidated financial statements at June 30, 2014.
	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. Through June 9, 2014, $1.375 billion of the Terrorism Coverage for 767 Fifth Avenue in excess of $250 million was provided by NYXP, LLC (“NYXP”), as a direct insurer. After June 9, 2014, all of the Terrorism Coverage for 767 Fifth Avenue has been provided by third party insurers. 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. 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 is 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 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 Salesforce Tower (formerly Transbay Tower) in San Francisco includes a $15 million per occurrence and annual aggregate limit of earthquake coverage (on July 28, 2014 this was increased to $60 million). 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, acted as a direct insurer with respect to a portion of the Company’s Terrorism Coverage for 767 Fifth Avenue through June 9, 2014. NYXP only insured losses which exceeded the program trigger under TRIA and NYXP reinsured 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	6 Months Ended
	Jun. 30, 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 June 30, 2014, the noncontrolling interests in the Company consisted of 16,458,014 OP Units, 1,511,796 LTIP Units, 394,590 2012 OPP Units, 314,974 2013 MYLTIP Units, 483,555 2014 MYLTIP Units 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 six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	99,609
	Net loss	(240		)
	Distributions	(2,300		)
	Adjustment to reflect redeemable interest at redemption value	6,709			-1
	Balance at June 30, 2014	$	103,778
	Balance at January 1, 2013	$	97,558
	Net loss	(980		)
	Distributions	(2,950		)
	Adjustment to reflect redeemable interest at redemption value	4,534
	Balance at June 30, 2013	$	98,162
	_______________
	(1) Includes an out-of-period adjustment totaling approximately $2.4 million (See Note 2).
	Noncontrolling Interest—Redeemable Preferred Units of the Company
	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 elected to convert such units into 1.312336 OP Units, or an aggregate of 874,168 OP Units, on or before May 12, 2014. As of May 12, 2014, the holders of all remaining 666,116 Series Two Preferred Units of partnership interest in the Company converted such units into an aggregate of 874,168 OP Units. The Series Two Preferred Units bore 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 were convertible into OP Units at a rate of $38.10 per Preferred Unit (1.312336 OP Units for each Preferred Unit). In connection with the conversion of the remaining Series Two Preferred Units in May 2014, the Company paid accrued and unpaid distributions which included the special cash distribution on an as-converted basis. On February 18, 2014, the Company paid a distribution on its outstanding Series Two Preferred Units of $0.85302 per unit. Due to the holders' redemption option existing outside the control of the Company’s general partner, the Series Two Preferred Units were presented outside of permanent equity in the Company's Consolidated Balance Sheets.
	The Preferred Units at June 30, 2014 consisted of 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. 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. In order to secure the performance of certain post-issuance obligations by the holders, all of such outstanding Series Four Preferred Units were subject to forfeiture pursuant to the terms of a pledge agreement and not eligible for redemption until and unless such security interest is released. On May 19, 2014, the Company released to the holders 319,687 Series Four Preferred Units that were previously subject to the security interest. On June 26, 2014, the Company notified the holders that it had elected to redeem such 319,687 Series Four Preferred Units on July 3, 2014 at the redemption price of $50.00 per unit, plus accrued and unpaid distributions. 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. See Note 12.
	On February 18, 2014, the Company paid a distribution on its outstanding Series Four Preferred Units of $0.25 per unit. On May 15, 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 six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	105,746
	Net income	939
	Distributions	(939		)
	Reallocation of partnership interest (1)	(87,740		)
	Balance at June 30, 2014	$	18,006
	Balance at January 1, 2013	$	199,378
	Net income	2,303
	Distributions	(2,303		)
	Reallocation of partnership interest	(444		)
	Balance at June 30, 2013	$	198,934
	_______________
	(1) Includes the conversion of the remaining 666,116 Series Two Preferred Units into 874,168 OP Units during the six months ended June 30, 2014.
	Noncontrolling Interest—Common Units of the Company
	During the six months ended June 30, 2014, 66,612 OP Units were presented by the holders for redemption (including 65,275 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 June 30, 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. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million during the six months ended June 30, 2014. 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 quarterly cash distribution on the OP Units and LTIP Units in the amount of $0.65 per unit, and a regular quarterly 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. On April 30, 2014, the Company paid 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, to holders of record as of the close of business on March 31, 2014. On June 19, 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 July 31, 2014 to holders of record as of the close of business on June 30, 2014.
	The following table reflects the activity of the noncontrolling interests—redeemable common units for the six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	1,710,218
	Contributions	23,990
	Net income	15,010
	Distributions	(22,673		)
	Conversion of redeemable partnership units	(2,241		)
	Unearned compensation	(11,091		)
	Accumulated other comprehensive loss	126
	Adjustment to reflect redeemable partnership units at redemption value	410,333
	Balance at June 30, 2014	$	2,123,672
	Balance at January 1, 2013	$	1,836,522
	Contributions	26,384
	Net income	57,177
	Distributions	(22,705		)
	Conversion of redeemable partnership units	(10,309		)
	Unearned compensation	(5,996		)
	Accumulated other comprehensive loss	127
	Adjustment to reflect redeemable partnership units at redemption value	(66,718		)
	Balance at June 30, 2013	$	1,814,482
	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 June 30, 2014 was approximately $2.1 billion based on the closing price of Boston Properties, Inc.’s common stock of $118.18 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 $721.1 million at June 30, 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 six months ended June 30, 2014 and 2013 (in thousands):
Balance at January 1, 2014	$	726,132
Capital contributions	1,675
Net income	5,438
Distributions	(12,149		)
Balance at June 30, 2014	$	721,096
Balance at January 1, 2013	$	(1,964	)
Fair value of capital recorded upon consolidation	483,488
Capital contributions	10,564
Net income (loss)	(1,199		)
Distributions	(1,500		)
Balance at June 30, 2013	$	489,389

Partners_Capital

Partners' Capital	6 Months Ended
	Jun. 30, 2014
Partners' Capital [Abstract]	'
Partners' Capital	'
	Partners’ Capital
	As of June 30, 2014, Boston Properties, Inc. owned 1,710,624 general partnership units and 151,381,950 limited partnership units.
	On June 3, 2014, Boston Properties, Inc. established a new “at the market” (ATM) stock offering program through which it may sell from time to time up to an aggregate of $600.0 million of its common stock through sales agents over a three-year period. This program replaces Boston Properties, Inc.'s prior $600.0 million ATM stock offering program that expired on June 2, 2014 with approximately $305.3 million of unsold common stock. Boston Properties, Inc. intends to use the net proceeds from any offering for general business purposes, which may include investment opportunities and debt reduction. Boston Properties, Inc. contributes the net proceeds from any such sales to the Company in exchange for a number of OP Units equal to the number of shares issued. No shares of common stock have been issued under this new ATM stock offering program.
	During the six months ended June 30, 2014, Boston Properties, Inc. acquired 66,612 OP Units in connection with the redemption of an equal number of redeemable OP Units from third parties.
	During the six months ended June 30, 2014, the Company issued 17,124 OP Units to Boston Properties, Inc. in connection with the exercise by certain employees of options to purchase Common Stock of Boston Properties, Inc.
	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 April 30, 2014, the Company paid a distribution of $0.65 per OP Unit to unitholders of record as of the close of business on March 31, 2014. On June 19, 2014, Boston Properties, Inc.'s Board of Directors declared a distribution of $0.65 per OP Unit payable on July 31, 2014 to unitholders of record as of the close of business on June 30, 2014.
	As of June 30, 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 May 15, 2014, the Company paid a distribution on its outstanding Series B Preferred Units of $32.8125 per unit. On June 19, 2014, Boston Properties, Inc.'s Board of Directors declared a distribution of $32.8125 per Series B Preferred Unit payable on August 15, 2014 to shareholders of record as of the close of business on August 5, 2014.

Earnings_Per_Common_Unit

Earnings Per Common Unit	6 Months Ended
	Jun. 30, 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 17,304,000 and 16,995,000 redeemable common units for the three months ended June 30, 2014 and 2013, respectively, and approximately 17,059,000 and 17,049,000 redeemable common units for the six months ended June 30, 2014 and 2013, respectively.
		For the three months ended June 30, 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	$	87,436		170,382	$	0.51
	Effect of Dilutive Securities:
	Stock Based Compensation	—			160	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	87,436		170,542	$	0.51
		For the three months ended June 30, 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	$	501,874		168,933	$	2.97
	Discontinued operations attributable to Boston Properties Limited Partnership	3,315			—	0.02
	Allocation of undistributed earnings to participating securities	(4,035		)	—	(0.02		)
	Net income attributable to Boston Properties Limited Partnership	$	501,154		168,933	$	2.97
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—			552	(0.01		)
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	501,154		169,485	$	2.96
		For the six months ended June 30, 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	$	149,655		170,113	$	0.88
	Effect of Dilutive Securities:
	Stock Based Compensation	—			149	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	149,655		170,262	$	0.88
		For the six months ended June 30, 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	$	542,419		168,842	$	3.21
	Discontinued operations attributable to Boston Properties Limited Partnership	23,693			—	0.14
	Allocation of undistributed earnings to participating securities	(3,536		)	—	(0.02		)
	Net income attributable to Boston Properties Limited Partnership	$	562,576		168,842	$	3.33
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—			429	(0.01		)
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	562,576		169,271	$	3.32

Stock_Option_and_Incentive_Pla

Stock Option and Incentive Plan	6 Months Ended
	Jun. 30, 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 FASB's 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 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. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million during the six months ended June 30, 2014. Accordingly, all 2011 OPP Unit awards were automatically forfeited.
	During the six months ended June 30, 2014, Boston Properties, Inc. issued 23,968 shares of restricted common stock, no non-qualified stock options and the Company issued 127,094 LTIP Units and 485,459 2014 MYLTIP Units to employees and non-employee directors under the 2012 Plan. Employees and non-employee directors 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 six months ended June 30, 2014 were valued at approximately $2.6 million ($109.27 per share weighted-average). The LTIP Units granted were valued at approximately $12.8 million ($100.61 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 $6.2 million and $6.4 million for the three months ended June 30, 2014 and 2013, respectively, and approximately $16.0 million and $31.9 million for the six months ended June 30, 2014 and 2013, respectively. On January 31, 2014, the measurement period for the Company’s 2011 OPP 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 Awards. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million. For the three and six months ended June 30, 2013, stock-based compensation expense includes approximately $1.6 million and $18.6 million, respectively, 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 June 30, 2014, there was $22.3 million of unrecognized compensation expense related to unvested restricted stock and LTIP Units and $18.6 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 3.1 years.

Segment_Information

Segment Information	6 Months Ended
	Jun. 30, 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 and six months ended June 30, 2013 as detailed below, have been included in the New York region. Accordingly, amounts reflected below for the New York region have been adjusted to reflect the Company's retrospective inclusion of the Princeton region 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, gains from early extinguishments of debt, income from unconsolidated joint ventures, gains on consolidation of 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. The Company's management also uses Net Operating Income to evaluate regional property level performance and to make decisions about resource allocations. Further, the Company believes Net Operating Income is useful to investors as a performance measure because, when compared across periods, Net Operating Income reflects the impact on operations from trends in occupancy rates, rental rates, operating costs and acquisition and development activity on an unleveraged basis, providing perspectives not immediately apparent from net income attributable to Boston Properties Limited Partnership.
	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 $1.6 million and $3.1 million for the three and six months ended June 30, 2013, respectively, and for Princeton these expenses, which totaled approximately $0.5 million and $0.9 million for the three and six months ended June 30, 2013, respectively, 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 June 30, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	173,128		$	223,899		$	57,450		$	94,222		$	548,699
	Office/Technical	5,912			—			6,341			3,671			15,924
	Residential	1,089			—			—			5,209			6,298
	Hotel	12,367			—			—			—			12,367
	Total	192,496			223,899			63,791			103,102			583,288
	% of Grand Totals	33		%	38.39		%	10.94		%	17.67		%	100		%
	Rental Expenses:
	Class A Office	65,818			74,962			21,282			32,481			194,543
	Office/Technical	1,736			—			1,308			1,123			4,167
	Residential	544			—			—			3,392			3,936
	Hotel	7,315			—			—			—			7,315
	Total	75,413			74,962			22,590			36,996			209,961
	% of Grand Totals	35.92		%	35.7		%	10.76		%	17.62		%	100		%
	Net operating income	$	117,083		$	148,937		$	41,201		$	66,106		$	373,327
	% of Grand Totals	31.36		%	39.89		%	11.04		%	17.71		%	100		%
	For the three months ended June 30, 2013:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	164,137		$	158,158		$	53,331		$	95,054		$	470,680
	Office/Technical	5,538			—			5,327			4,031			14,896
	Residential	1,065			—			—			4,419			5,484
	Hotel	11,118			—			—			—			11,118
	Total	181,858			158,158			58,658			103,504			502,178
	% of Grand Totals	36.21		%	31.49		%	11.68		%	20.62		%	100		%
	Rental Expenses:
	Class A Office	62,693			55,357			19,657			31,711			169,418
	Office/Technical	1,627			—			1,116			1,027			3,770
	Residential	407			—			—			2,423			2,830
	Hotel	7,335			—			—			—			7,335
	Total	72,062			55,357			20,773			35,161			183,353
	% of Grand Totals	39.3		%	30.19		%	11.33		%	19.18		%	100		%
	Net operating income	$	109,796		$	102,801		$	37,885		$	68,343		$	318,825
	% of Grand Totals	34.44		%	32.24		%	11.88		%	21.44		%	100		%
	For the six months ended June 30, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	344,070		$	441,207		$	112,058		$	191,270		$	1,088,605
	Office/Technical	11,732			—			12,558			7,331			31,621
	Residential	2,252			—			—			9,728			11,980
	Hotel	20,560			—			—			—			20,560
	Total	378,614			441,207			124,616			208,329			1,152,766
	% of Grand Totals	32.84		%	38.28		%	10.81		%	18.07		%	100		%
	Rental Expenses:
	Class A Office	137,216			149,333			40,595			65,920			393,064
	Office/Technical	3,425			—			2,522			2,325			8,272
	Residential	992			—			—			6,706			7,698
	Hotel	14,112			—			—			—			14,112
	Total	155,745			149,333			43,117			74,951			423,146
	% of Grand Totals	36.81		%	35.29		%	10.19		%	17.71		%	100		%
	Net operating income	$	222,869		$	291,874		$	81,499		$	133,378		$	729,620
% of Grand Totals	30.55		%	40		%	11.17		%	18.28		%	100		%
For the six months ended June 30, 2013:
	Boston			New York			San			Washington,			Total
							Francisco			DC
Rental Revenue:
Class A Office	$	324,961		$	296,681		$	106,002		$	188,413		$	916,057
Office/Technical	11,191			—			5,478			8,074			24,743
Residential	2,132			—			—			8,930			11,062
Hotel	19,409			—			—			—			19,409
Total	357,693			296,681			111,480			205,417			971,271
% of Grand Totals	36.83		%	30.54		%	11.48		%	21.15		%	100		%
Rental Expenses:
Class A Office	127,979			104,445			38,030			62,467			332,921
Office/Technical	3,414			—			1,151			2,031			6,596
Residential	850			—			—			4,713			5,563
Hotel	14,379			—			—			—			14,379
Total	146,622			104,445			39,181			69,211			359,459
% of Grand Totals	40.79		%	29.06		%	10.9		%	19.25		%	100		%
Net operating income	$	211,071		$	192,236		$	72,299		$	136,206		$	611,812
% of Grand Totals	34.5		%	31.42		%	11.82		%	22.26		%	100		%
The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership:
	Three months ended						Six months ended June 30,
	June 30,
	2014			2013			2014			2013
	(in thousands)
Net Operating Income	$	373,327		$	318,825		$	729,620		$	611,812
Add:
Development and management services income	6,506			7,855			11,722			16,588
Income from unconsolidated joint ventures	2,834			48,783			5,650			57,504
Gain on consolidation of joint ventures	—			387,801			—			387,801
Interest and other income	2,109			1,296			3,420			2,767
Gains from investments in securities	662			181			948			916
Gains from early extinguishments of debt	—			152			—			152
Income from discontinued operations	—			3,315			—			5,809
Gain on forgiveness of debt from discontinued operations	—			—			—			20,736
Less:
General and administrative expense	23,271			24,316			53,176			69,832
Transaction costs	661			535			1,098			978
Depreciation and amortization expense	152,602			131,506			304,847			248,915
Interest expense	110,977			103,140			224,531			203,573
Impairment loss	—			—			—			4,401
Impairment loss from discontinued operations	—			—			—			2,852
Noncontrolling interest in property partnerships	7,553			(219		)	11,907			2,355
Noncontrolling interest—redeemable preferred units	2,938			3,741			6,146			5,067
Net income attributable to Boston Properties Limited Partnership	$	87,436		$	505,189		$	149,655		$	566,112

Subsequent_Events

Subsequent Events	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	On July 1, 2014, the Company used available cash to repay the mortgage loan collateralized by its New Dominion Technology Park Building Two property located in Herndon, Virginia totaling $63.0 million. The mortgage loan bore interest at a fixed rate of 5.55% per annum and was scheduled to mature on October 1, 2014. There was no prepayment penalty.
	On July 3, 2014, the Company redeemed 319,687 Series Four Preferred Units for cash totaling approximately $16.0 million. An aggregate of 40,440 Series Four Preferred Units remain outstanding and subject to a security interest under a pledge agreement.
	On July 23, 2014, the tenant exercised the purchase option under its ground lease at the Company’s Broad Run Business Park property located in Loudoun County, Virginia for a sale price of approximately $9.8 million. Broad Run Business Park is an approximately 15.5 acre land parcel subject to the ground lease with the tenant that was scheduled to expire on October 31, 2048. The sale is subject to the satisfaction of customary closing conditions and there can be no assurance that the sale will be consummated on the terms currently contemplated or at all.
	On July 29, 2014, the Company completed the sale of its Mountain View Technology Park properties and Mountain View Research Park Building Sixteen property located in Mountain View, California for an aggregate sale price of approximately $92.1 million. Mountain View Technology Park is a seven-building complex of Office/Technical properties aggregating approximately 135,000 net rentable square feet. Mountain View Research Park Building Sixteen is an Office/Technical property with approximately 63,000 net rentable square feet.

Basis_Of_Presentation_And_Summ1

Basis Of Presentation And Summary Of Significant Accounting Policies Recent Accounting Pronouncement (Policies)	6 Months Ended
	Jun. 30, 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.
	In May 2014, the FASB issued ASU 2014-09, "Revenue from Contract with Customers (Topic 606)" ("ASU 2014-09"). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying ASU 2014-09, companies will perform a five-step analysis of transactions to determine when and how revenue is recognized. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB's Accounting Standards Codification ("ASC"). ASU 2014-09 is effective for annual reporting periods (including interim periods within that reporting period) beginning after December 15, 2016 and shall be applied using either a full retrospective or modified retrospective approach. Early application is not permitted. The Company is currently assessing the potential impact that the adoption of ASU 2014-09 will have on its consolidated financial statements.
	In June 2014, the FASB issued ASU No. 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period” (“ASU 2014-12”). The amendments in ASU 2014-12 require that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in ASC Topic No. 718, “Compensation - Stock Compensation” (“ASC 718”), as it relates to awards with performance conditions that affect vesting to account for such awards. The amendments in ASU 2014-12 are effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Early adoption is permitted. Entities may apply the amendments in ASU 2014-12 either: (a) prospectively to all awards granted or modified after the effective date; or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The Company does not expect the adoption of ASU 2014-12 to have a material impact on its consolidated financial statements.

Basis_Of_Presentation_And_Summ2

Basis Of Presentation And Summary Of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2014 and December 31, 2013 (in thousands):
		June 30, 2014				December 31, 2013
		Carrying		Estimated		Carrying			Estimated
		Amount		Fair Value		Amount			Fair Value
	Mortgage notes payable	$	4,411,453	$	4,547,761	$	4,449,734		$	4,545,283
	Mezzanine notes payable	310,427		310,457		311,040			311,064
	Unsecured senior notes	5,836,729		6,229,201		5,835,854			6,050,517
	Unsecured exchangeable senior notes	—		—		744,880		-1	750,266
	Total	$	10,558,609	$	11,087,419	$	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 Six Months Ended June 30, 2014 (Tables)	6 Months Ended
	Jun. 30, 2014
Real Estate [Abstract]	'
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	'
		For the three months ended June 30,		For the six months ended June 30,
		2013		2013
		(in thousands)
	Total revenue	$	6,815	$	13,850
	Expenses
	Operating	2,352		4,795
	Depreciation and amortization	1,148		2,886
	Total expenses	3,500		7,681
	Operating income	3,315		6,169
	Other expense
	Interest expense	—		360
	Income from discontinued operations	$	3,315	$	5,809
	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)	6 Months Ended
	Jun. 30, 2014
Investments In Unconsolidated Joint Ventures [Abstract]	'
Investments In Unconsolidated Joint Ventures	'
	The investments in unconsolidated joint ventures consist of the following at June 30, 2014:
	Entity		Properties		Nominal %				Carrying Value of Investment
					Ownership
									(in thousands)
	Square 407 Limited Partnership		Market Square North		50	%			$	(9,112	)
	The Metropolitan Square Associates LLC		Metropolitan Square		51	%			6,561
	BP/CRF 901 New York Avenue LLC		901 New York Avenue		25	%	(1)		(1,974		)
	WP Project Developer LLC		Wisconsin Place Land and Infrastructure		33.3	%	(2)		46,455
	Annapolis Junction NFM, LLC		Annapolis Junction		50	%	(3)		23,763
	2 GCT Venture LLC		N/A		60	%	-4		326
	540 Madison Venture LLC		540 Madison Avenue		60	%			69,664
	500 North Capitol LLC		500 North Capitol Street, NW		30	%			(862		)
	501 K Street LLC		501 K Street		50	%	-5		42,118
									$	176,939
	_______________
	-1	The Company’s economic ownership has increased 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 joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels.
	-4	Two Grand Central Tower was sold on October 25, 2011.
	-5	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
Balance Sheets Of The Unconsolidated Joint Ventures	'
	The combined summarized balance sheets of the Company's unconsolidated joint ventures are as follows:
		June 30, 2014				31-Dec-13
		(in thousands)
	ASSETS
	Real estate and development in process, net	$	1,010,834			$	924,297
	Other assets	175,872				163,149
	Total assets	$	1,186,706			$	1,087,446
	LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
	Mortgage and notes payable	$	747,988			$	749,732
	Other liabilities	26,704				28,830
	Members’/Partners’ equity	412,014				308,884
	Total liabilities and members’/partners’ equity	$	1,186,706			$	1,087,446
	Company’s share of equity	$	205,134			$	154,726
	Basis differentials (1)	(28,195		)		(28,642		)
	Carrying value of the Company’s investments in unconsolidated joint ventures	$	176,939			$	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 June 30,								For the six months ended June 30,
		2014				2013				2014		2013
		(in thousands)
	Total revenue (1)	$	38,437			$	99,831			$	76,471	$	235,481
	Expenses
	Operating	15,461				32,497				30,925		74,863
	Depreciation and amortization	9,167				27,141				18,259		66,418
	Total expenses	24,628				59,638				49,184		141,281
	Operating income	13,809				40,193				27,287		94,200
	Other expense
	Interest expense	7,984				40,054				15,996		96,288
	Losses from early extinguishment of debt	—				1,677				—		1,677
	Income (loss) from continuing operations	5,825				(1,538		)		11,291		(3,765		)
	Gain on sale of real estate	—				1,766				—		1,766
	Net income (loss)	$	5,825			$	228			$	11,291	$	(1,999	)
	Company’s share of net income (loss)	$	2,578			$	683			$	5,203	$	(1,175	)
	Gain on sale of real estate	—				43,327				—		43,327
	Basis differential	256				(2,070		)		447		(1,626		)
	Elimination of inter-entity interest on partner loan	—				6,843				—		16,978
	Income from unconsolidated joint ventures	$	2,834			$	48,783			$	5,650	$	57,504
	Gains on consolidation of joint ventures	$	—			$	387,801			$	—	$	387,801
	_______________
	-1	Includes straight-line rent adjustments of $0.3 million and $3.1 million for the three months ended June 30, 2014 and 2013, respectively, and $0.9 million and $7.1 million for the six months ended June 30, 2014 and 2013, respectively. Includes net below-market rent adjustments of $(0.1) million and $13.5 million for the three months ended June 30, 2014 and 2013, respectively, and $0.0 million and $34.0 million for the six months ended June 30, 2014 and 2013, respectively.

Noncontrolling_Interests_Table

Noncontrolling Interests (Tables)	6 Months Ended
	Jun. 30, 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 six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	99,609
	Net loss	(240		)
	Distributions	(2,300		)
	Adjustment to reflect redeemable interest at redemption value	6,709			-1
	Balance at June 30, 2014	$	103,778
	Balance at January 1, 2013	$	97,558
	Net loss	(980		)
	Distributions	(2,950		)
	Adjustment to reflect redeemable interest at redemption value	4,534
	Balance at June 30, 2013	$	98,162
Schedule Of Series Two Preferred Units	'
	The following table reflects the activity of the noncontrolling interests—redeemable preferred units of the Company for the six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	105,746
	Net income	939
	Distributions	(939		)
	Reallocation of partnership interest (1)	(87,740		)
	Balance at June 30, 2014	$	18,006
	Balance at January 1, 2013	$	199,378
	Net income	2,303
	Distributions	(2,303		)
	Reallocation of partnership interest	(444		)
	Balance at June 30, 2013	$	198,934
	_______________
	(1) Includes the conversion of the remaining 666,116 Series Two Preferred Units into 874,168 OP Units during the six months ended June 30, 2014
Noncontrolling Interests-Redeemable Common Units	'
	The following table reflects the activity of the noncontrolling interests—redeemable common units for the six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	1,710,218
	Contributions	23,990
	Net income	15,010
	Distributions	(22,673		)
	Conversion of redeemable partnership units	(2,241		)
	Unearned compensation	(11,091		)
	Accumulated other comprehensive loss	126
	Adjustment to reflect redeemable partnership units at redemption value	410,333
	Balance at June 30, 2014	$	2,123,672
	Balance at January 1, 2013	$	1,836,522
	Contributions	26,384
	Net income	57,177
	Distributions	(22,705		)
	Conversion of redeemable partnership units	(10,309		)
	Unearned compensation	(5,996		)
	Accumulated other comprehensive loss	127
	Adjustment to reflect redeemable partnership units at redemption value	(66,718		)
	Balance at June 30, 2013	$	1,814,482
Noncontrolling Interests-Property Partnerships	'
	The following table reflects the activity of the noncontrolling interests in property partnerships for the six months ended June 30, 2014 and 2013 (in thousands):
	Balance at January 1, 2014	$	726,132
	Capital contributions	1,675
	Net income	5,438
	Distributions	(12,149		)
	Balance at June 30, 2014	$	721,096
	Balance at January 1, 2013	$	(1,964	)
	Fair value of capital recorded upon consolidation	483,488
	Capital contributions	10,564
	Net income (loss)	(1,199		)
	Distributions	(1,500		)
	Balance at June 30, 2013	$	489,389

Earnings_Per_Common_Unit_Table

Earnings Per Common Unit (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Computation Of Basic And Diluted Earnings Per Unit	'
	approximately 17,304,000 and 16,995,000 redeemable common units for the three months ended June 30, 2014 and 2013, respectively, and approximately 17,059,000 and 17,049,000 redeemable common units for the six months ended June 30, 2014 and 2013, respectively.
		For the three months ended June 30, 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	$	87,436		170,382	$	0.51
	Effect of Dilutive Securities:
	Stock Based Compensation	—			160	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	87,436		170,542	$	0.51
		For the three months ended June 30, 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	$	501,874		168,933	$	2.97
	Discontinued operations attributable to Boston Properties Limited Partnership	3,315			—	0.02
	Allocation of undistributed earnings to participating securities	(4,035		)	—	(0.02		)
	Net income attributable to Boston Properties Limited Partnership	$	501,154		168,933	$	2.97
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—			552	(0.01		)
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	501,154		169,485	$	2.96
		For the six months ended June 30, 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	$	149,655		170,113	$	0.88
	Effect of Dilutive Securities:
	Stock Based Compensation	—			149	—
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	149,655		170,262	$	0.88
		For the six months ended June 30, 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	$	542,419		168,842	$	3.21
	Discontinued operations attributable to Boston Properties Limited Partnership	23,693			—	0.14
	Allocation of undistributed earnings to participating securities	(3,536		)	—	(0.02		)
	Net income attributable to Boston Properties Limited Partnership	$	562,576		168,842	$	3.33
	Effect of Dilutive Securities:
	Stock Based Compensation and Exchangeable Senior Notes	—			429	(0.01		)
	Diluted Earnings:
	Net income attributable to Boston Properties Limited Partnership	$	562,576		169,271	$	3.32

Segment_Information_Tables

Segment Information (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	173,128		$	223,899		$	57,450		$	94,222		$	548,699
	Office/Technical	5,912			—			6,341			3,671			15,924
	Residential	1,089			—			—			5,209			6,298
	Hotel	12,367			—			—			—			12,367
	Total	192,496			223,899			63,791			103,102			583,288
	% of Grand Totals	33		%	38.39		%	10.94		%	17.67		%	100		%
	Rental Expenses:
	Class A Office	65,818			74,962			21,282			32,481			194,543
	Office/Technical	1,736			—			1,308			1,123			4,167
	Residential	544			—			—			3,392			3,936
	Hotel	7,315			—			—			—			7,315
	Total	75,413			74,962			22,590			36,996			209,961
	% of Grand Totals	35.92		%	35.7		%	10.76		%	17.62		%	100		%
	Net operating income	$	117,083		$	148,937		$	41,201		$	66,106		$	373,327
	% of Grand Totals	31.36		%	39.89		%	11.04		%	17.71		%	100		%
	For the three months ended June 30, 2013:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	164,137		$	158,158		$	53,331		$	95,054		$	470,680
	Office/Technical	5,538			—			5,327			4,031			14,896
	Residential	1,065			—			—			4,419			5,484
	Hotel	11,118			—			—			—			11,118
	Total	181,858			158,158			58,658			103,504			502,178
	% of Grand Totals	36.21		%	31.49		%	11.68		%	20.62		%	100		%
	Rental Expenses:
	Class A Office	62,693			55,357			19,657			31,711			169,418
	Office/Technical	1,627			—			1,116			1,027			3,770
	Residential	407			—			—			2,423			2,830
	Hotel	7,335			—			—			—			7,335
	Total	72,062			55,357			20,773			35,161			183,353
	% of Grand Totals	39.3		%	30.19		%	11.33		%	19.18		%	100		%
	Net operating income	$	109,796		$	102,801		$	37,885		$	68,343		$	318,825
	% of Grand Totals	34.44		%	32.24		%	11.88		%	21.44		%	100		%
	For the six months ended June 30, 2014:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	344,070		$	441,207		$	112,058		$	191,270		$	1,088,605
	Office/Technical	11,732			—			12,558			7,331			31,621
	Residential	2,252			—			—			9,728			11,980
	Hotel	20,560			—			—			—			20,560
	Total	378,614			441,207			124,616			208,329			1,152,766
	% of Grand Totals	32.84		%	38.28		%	10.81		%	18.07		%	100		%
	Rental Expenses:
	Class A Office	137,216			149,333			40,595			65,920			393,064
	Office/Technical	3,425			—			2,522			2,325			8,272
	Residential	992			—			—			6,706			7,698
	Hotel	14,112			—			—			—			14,112
	Total	155,745			149,333			43,117			74,951			423,146
	% of Grand Totals	36.81		%	35.29		%	10.19		%	17.71		%	100		%
	Net operating income	$	222,869		$	291,874		$	81,499		$	133,378		$	729,620
	% of Grand Totals	30.55		%	40		%	11.17		%	18.28		%	100		%
	For the six months ended June 30, 2013:
		Boston			New York			San			Washington,			Total
								Francisco			DC
	Rental Revenue:
	Class A Office	$	324,961		$	296,681		$	106,002		$	188,413		$	916,057
Office/Technical	11,191			—			5,478			8,074			24,743
Residential	2,132			—			—			8,930			11,062
Hotel	19,409			—			—			—			19,409
Total	357,693			296,681			111,480			205,417			971,271
% of Grand Totals	36.83		%	30.54		%	11.48		%	21.15		%	100		%
Rental Expenses:
Class A Office	127,979			104,445			38,030			62,467			332,921
Office/Technical	3,414			—			1,151			2,031			6,596
Residential	850			—			—			4,713			5,563
Hotel	14,379			—			—			—			14,379
Total	146,622			104,445			39,181			69,211			359,459
% of Grand Totals	40.79		%	29.06		%	10.9		%	19.25		%	100		%
Net operating income	$	211,071		$	192,236		$	72,299		$	136,206		$	611,812
% of Grand Totals	34.5		%	31.42		%	11.82		%	22.26		%	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						Six months ended June 30,
		June 30,
		2014			2013			2014			2013
		(in thousands)
	Net Operating Income	$	373,327		$	318,825		$	729,620		$	611,812
	Add:
	Development and management services income	6,506			7,855			11,722			16,588
	Income from unconsolidated joint ventures	2,834			48,783			5,650			57,504
	Gain on consolidation of joint ventures	—			387,801			—			387,801
	Interest and other income	2,109			1,296			3,420			2,767
	Gains from investments in securities	662			181			948			916
	Gains from early extinguishments of debt	—			152			—			152
	Income from discontinued operations	—			3,315			—			5,809
	Gain on forgiveness of debt from discontinued operations	—			—			—			20,736
	Less:
	General and administrative expense	23,271			24,316			53,176			69,832
	Transaction costs	661			535			1,098			978
	Depreciation and amortization expense	152,602			131,506			304,847			248,915
	Interest expense	110,977			103,140			224,531			203,573
	Impairment loss	—			—			—			4,401
	Impairment loss from discontinued operations	—			—			—			2,852
	Noncontrolling interest in property partnerships	7,553			(219		)	11,907			2,355
	Noncontrolling interest—redeemable preferred units	2,938			3,741			6,146			5,067
	Net income attributable to Boston Properties Limited Partnership	$	87,436		$	505,189		$	149,655		$	566,112

Organization_Details

Organization (Details) (USD $)

6 Months Ended

6 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

sqft

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]

Retail Properties Under Construction [Member]

Residential Properties [Member]

series four preferred units [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Series B Preferred Units [Member]

depositary shares [Member]

Vehicles

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

Real_Estate_Properties

Series B Cumulative Redeemable Preferred Stock [Member]

acre

sqft

sqft

Y

Real Estate Properties [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

89.50%

89.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

Number of series of preferred units outstanding

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of real estate properties

'

'

180

13

171

132

12

39

1

5

1

3

'

'

'

'

'

Net Rentable Area (in sf)

'

'

46,600,000

4,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of vehicles in structured parking

46,145

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Area of parking structures (in square feet)

15,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Area of undeveloped land parcels owned (in acres)

492.1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2013
Accounting Policies [Abstract]	'	'	'
Cumulative non-cash adjustment to the accretion of the changes in the redemption value of the noncontrolling interest	$2.40	'	'
Reclassification between general and administrative expense and real estate operating expense	'	$2.10	$4

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 $)	Jun. 30, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]	'	'
Mortgage notes payable	$4,411,453,000	$4,449,734,000
Mezzanine notes payable	310,427,000	311,040,000
Unsecured senior notes	5,836,729,000	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	4,411,453,000	4,449,734,000
Mezzanine notes payable	310,427,000	311,040,000
Unsecured senior notes	5,836,729,000	5,835,854,000
Unsecured exchangeable senior notes	0	744,880,000	[1]
Total	10,558,609,000	11,341,508,000
Estimated Fair Value [Member]	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'
Mortgage notes payable	4,547,761,000	4,545,283,000
Mezzanine notes payable	310,457,000	311,064,000
Unsecured senior notes	6,229,201,000	6,050,517,000
Unsecured exchangeable senior notes	0	750,266,000
Total	11,087,419,000	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 December 31, 2013.

Real_Estate_Activity_During_th2

Real Estate Activity During the Six Months Ended June 30, 2014 (Narrative) (Details) (USD $)	Jun. 11, 2014	Feb. 10, 2014	Apr. 01, 2014	20-May-14	20-May-14	Apr. 03, 2014	Apr. 10, 2014	Apr. 10, 2014
In Millions, unless otherwise specified	Patriots park [Member]	The Avant at Reston Town Center Residential [Member]	99 Third Avenue [Member]	888 Boylston Street [Member]	10 CityPoint [Member]	690 Folsom Street [Member]	Salesforece Tower (formerly Transbay Tower) [Member]	Salesforece Tower (formerly Transbay Tower) [Member]
	Buildings	apartments	sqft	sqft	sqft	sqft	sqft	Company [Member]
	sqft	sqft					floor
Real Estate Properties [Line Items]	'	'	'	'	'	'	'	'
Contractual Sales Price	$321	'	'	'	'	'	'	'
Number of real estate properties	3	'	'	'	'	'	'	'
Number of apartment units	'	359	'	'	'	'	'	'
Net Rentable Area (in sf)	706,000	355,000	17,000	425,000	245,000	26,000	1,400,000	'
Ownership Percentage	'	'	'	'	'	'	'	95.00%
Square Footage Of Signed Lease	'	'	'	'	'	'	714,000	'
Number of floors real estate	'	'	'	'	'	'	61	'

Real_Estate_Activity_During_th3

Real Estate Activity During the Six Months Ended June 30, 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		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'
Total revenue	$589,794	$510,033	$1,164,488	$987,859
Expenses	'	'	'	'
Depreciation and amortization	152,602	131,506	304,847	248,915
Total expenses	386,495	339,710	782,267	683,585
Operating income	203,299	170,323	382,221	304,274
Other expense	'	'	'	'
Interest expense	110,977	103,140	224,531	203,573
Income from discontinued operations	'	3,315	'	23,693
Gain on forgiveness of debt from discontinued operations attributable to Boston Properties LImited Partnership	0	0	0	20,736
Impairment loss from discontinued operations attributable to Boston Properties Limited Partnership	0	0	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	'	6,815	'	13,850
Expenses	'	'	'	'
Operating	'	2,352	'	4,795
Depreciation and amortization	'	1,148	'	2,886
Total expenses	'	3,500	'	7,681
Operating income	'	3,315	'	6,169
Other expense	'	'	'	'
Interest expense	'	0	'	360
Income from discontinued operations	'	3,315	'	5,809
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)

Investments_in_Unconsolidated_2

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

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 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]

Annapolis Junction NFM, LLC [Member]

2 GCT Venture LLC [Member]

540 Madison Venture LLC [Member]

500 North Capitol LLC [Member]

Entity Owning Land And Infrastructure Of Project [Member]

501 K Street [Member]

Buildings

Land_Parcels

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Properties

'

'

'Market Square North

'Metropolitan Square

'901 New York Avenue

'Wisconsin Place Land and Infrastructure

'Annapolis Junction

'N/A

[1]

'540 Madison Avenue

'500 North Capitol Street, NW

'

'501 K Street

Ownership Percentage

'

'

50.00%

51.00%

25.00%

[2]

33.30%

[3]

50.00%

[4]

60.00%

[1]

60.00%

30.00%

33.30%

50.00%

[5]

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

$176,939

$126,084

($9,112)

$6,561

($1,974)

$46,455

$23,763

$326

$69,664

($862)

'

$42,118

Number of real estate properties

'

'

'

'

'

'

2

'

'

'

'

'

Number of buildings under construction

'

'

'

'

'

'

2

'

'

'

'

'

Parcels of undeveloped land

'

'

'

'

'

'

2

'

'

'

'

'

[1]

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

[2]

The Company’s economic ownership has increased based on the achievement of certain return thresholds.

[3]

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.

[4]

The joint venture owns two in-service buildings, two buildings under construction and two undeveloped land parcels.

[5]

Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Investments_in_Unconsolidated_3

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) (USD $)	Jun. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'		'
Real estate and development in process, net	$15,533,337		$15,451,531
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY	'		'
Mortgage and notes payable	4,411,453		4,449,734
Other liabilities	539,716		578,969
Total liabilities and capital	18,536,921		19,796,588
Carrying value of the Company's investments in unconsolidated joint ventures	176,939		126,084
Unconsolidated Joint Ventures [Member]	'		'
ASSETS	'		'
Real estate and development in process, net	1,010,834		924,297
Other assets	175,872		163,149
Total assets	1,186,706		1,087,446
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY	'		'
Mortgage and notes payable	747,988		749,732
Other liabilities	26,704		28,830
Members'/Partners' equity	412,014		308,884
Total liabilities and capital	1,186,706		1,087,446
Company's share of equity	205,134		154,726
Basis differentials	-28,195	[1]	-28,642	[1]
Carrying value of the Company's investments in unconsolidated joint ventures	$176,939		$126,084
[1]	unt 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.

Investments_in_Unconsolidated_4

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Schedule of Equity Method Investments [Line Items]	'		'		'		'
Total revenue	$589,794,000		$510,033,000		$1,164,488,000		$987,859,000
Expenses	'		'		'		'
Depreciation and amortization	152,602,000		131,506,000		304,847,000		248,915,000
Total expenses	386,495,000		339,710,000		782,267,000		683,585,000
Operating income	203,299,000		170,323,000		382,221,000		304,274,000
Other expense	'		'		'		'
Interest expense	110,977,000		103,140,000		224,531,000		203,573,000
Losses from Early Extinguishment of Debt	0		-152,000		0		-152,000
Income (loss) from continuing operations	97,927,000		505,396,000		167,708,000		549,841,000
Net income	97,927,000		508,711,000		167,708,000		573,534,000
Income from unconsolidated joint ventures	2,834,000		48,783,000		5,650,000		57,504,000
Gains on Consolidation of Joint Ventures	0		-387,801,000		0		-387,801,000
Unconsolidated Joint Ventures [Member]	'		'		'		'
Schedule of Equity Method Investments [Line Items]	'		'		'		'
Total revenue	38,437,000	[1]	99,831,000	[1]	76,471,000	[1]	235,481,000	[1]
Expenses	'		'		'		'
Operating	15,461,000		32,497,000		30,925,000		74,863,000
Depreciation and amortization	9,167,000		27,141,000		18,259,000		66,418,000
Total expenses	24,628,000		59,638,000		49,184,000		141,281,000
Operating income	13,809,000		40,193,000		27,287,000		94,200,000
Other expense	'		'		'		'
Interest expense	7,984,000		40,054,000		15,996,000		96,288,000
Losses from Early Extinguishment of Debt	0		1,677,000		0		1,677,000
Income (loss) from continuing operations	5,825,000		-1,538,000		11,291,000		-3,765,000
Gain on sale of real estate	0		1,766,000		0		1,766,000
Net income	5,825,000		228,000		11,291,000		-1,999,000
Company's share of net income (loss)	2,578,000		683,000		5,203,000		-1,175,000
Gain on sale of real estate	0		43,327,000		0		43,327,000
Basis differential	256,000		-2,070,000		447,000		-1,626,000
Elimination of inter-entity interest on partner loan	0		6,843,000		0		16,978,000
Income from unconsolidated joint ventures	2,834,000		48,783,000		5,650,000		57,504,000
Gains on Consolidation of Joint Ventures	0		-387,801,000		0		-387,801,000
Straight Line Rent Adjustments	300,000		3,100,000		900,000		7,100,000
Below market rent adjustments, net	($100,000)		$13,500,000		$0		$34,000,000
[1]	(1)Includes straight-line rent adjustments of $0.3 million and $3.1 million for the three months ended June 30, 2014 and 2013, respectively, and $0.9 million and $7.1 million for the six months ended June 30, 2014 and 2013, respectively. Includes net below-market rent adjustments of $(0.1) million and $13.5 million for the three months ended June 30, 2014 and 2013, respectively, and $0.0 million and $34.0 million for the six months ended June 30, 2014 and 2013, respectively.

Investments_in_Unconsolidated_5

Investments in Unconsolidated Joint Ventures Investment in Unconsolidated Joint ventures (Narrative) (Details) (USD $)	6 Months Ended		0 Months Ended			0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Apr. 10, 2014	Jun. 30, 2014		Jun. 23, 2014	Apr. 30, 2014	Apr. 10, 2014	Apr. 10, 2014	Apr. 30, 2014
			501 K Street [Member]	501 K Street [Member]		Annapolis Junction Building Eight [Member]	Annapolis Junction Building Eight [Member]	joint venture partner [Member]	Company [Member]	Company [Member]
			sqft			Y	sqft	501 K Street [Member]	501 K Street [Member]	Annapolis Junction Building Eight [Member]
Schedule of Equity Method Investments [Line Items]	'	'	'	'		'	'	'	'	'
Debt Instrument, Description of Variable Rate Basis	'	'	'	'		' LIBOR plus 1.50%	'	'	'	'
Capital contributions to unconsolidated joint ventures	$47,767,000	$0	$39,000,000	'		'	$5,400,000	'	'	'
Ownership Percentage	'	'	'	50.00%	[1]	'	'	50.00%	50.00%	50.00%
Net Rentable Area (in sf)	'	'	520,000	'		'	125,000	'	'	'
Construction Loan Facility Borrowing Capacity	'	'	'	'		$26,000,000	'	'	'	'
Debt Instrument, Basis Spread on Variable Rate	'	'	'	'		1.50%	'	'	'	'
Maturity Date	'	'	'	'		23-Jun-17	'	'	'	'
Number of extensions	'	'	'	'		2	'	'	'	'
Extension Option (in years)	'	'	'	'		1	'	'	'	'
[1]	Under the joint venture agreement, the partner will be entitled to up to two additional payments from the venture based on increases in total square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.

Unsecured_Exchangeable_Senior_1

Unsecured Exchangeable Senior Notes Unsecured exchangeable Senior Notes (Narrative) (details) (Three point six two five percent exchangeable senior notes [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 18, 2014
Three point six two five percent 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 $)	6 Months Ended	5 Months Ended		3 Months Ended	12 Months Ended		3 Months Ended		6 Months Ended		0 Months Ended
	Jun. 30, 2014	Jun. 09, 2014	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2009	Jan. 10, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jul. 28, 2014
		767 Venture, LLC [Member]	767 Venture, LLC [Member]	Lehman [Member]	Lehman [Member]	Lehman [Member]	Lehman [Member]	Lehman [Member]	601 Lexington Avenue [Member]	John Hancock Tower [Member]	Subsequent Event [Member]
							Minimum [Member]	Maximum [Member]
Commitments And Contingencies [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Letter of credit and performance obligations	$13,200,000	'	'	'	'	'	'	'	'	'	'
Maximum funding obligation	'	'	22,400,000	'	'	'	'	'	'	'	'
Guarantee Obligation Related To Tenant Re-Leasing Costs	'	'	'	'	'	'	'	'	'	30,500,000	'
Property insurance program per occurrence limits	1,000,000,000	'	1,625,000,000	'	'	'	'	'	'	'	'
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	'	'	'	'	'	'	'	'	250,000,000	'	'
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	'	'	'	'	'	'	'	'	'
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 SalesforceTower	15,000,000	'	'	'	'	'	'	'	'	'	60,000,000
Operating partnership guarantee to cover liabilities of IXP	20,000,000	'	'	'	'	'	'	'	'	'	'
Maturity Date	'	'	'	'	'	'	'	'	'	6-Jan-17	'
Bankruptcy claim, amount filed by general creditor	'	'	'	'	45,300,000	'	'	'	'	'	'
Bankruptcy claim amount allowed by court to creditor	'	'	'	'	'	$45,200,000	'	'	'	'	'
Bankruptcy claim, price on the private market	'	'	'	'	'	'	0.4	0.41	'	'	'
Bankruptcy claim, denominator used to evaluate claim price amount	'	'	'	1	'	'	'	'	'	'	'

Noncontrolling_Interests_Narra

Noncontrolling Interests (Narrative) (Details)	Jun. 30, 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)	16,458,014
Long-Term Incentive Plan (LTIP) Units (in shares)	1,511,796
Series Four Preferred Units (in shares)	360,126
2012 OPP Units [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
2014 MYLTIP Units [Member]	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'
2014 MYLTIP	483,555

Noncontrolling_Interests_Redee

Noncontrolling Interests (Redeemable Preferred Units) (Narrative) (Details) (USD $)

Jun. 30, 2014

Mar. 11, 2014

12-May-14

Jun. 30, 2014

Feb. 18, 2014

Jun. 30, 2014

Jun. 30, 2014

Jul. 03, 2014

Jun. 26, 2014

19-May-14

15-May-14

Feb. 18, 2014

Noncontrolling Interests [Member]

Series Two Preferred Units [Member]

Series Two Preferred Units [Member]

Series Two Preferred Units [Member]

Series Two Preferred Units [Member]

series four preferred units [Member]

series four preferred units [Member]

series four preferred units [Member]

series four preferred units [Member]

series four preferred units [Member]

series four preferred units [Member]

series four preferred units [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [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

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

874,168

874,168

'

'

'

'

'

'

'

'

Distributions to Series Two Preferred Units (in dollars per share)

'

'

'

'

$0.85

'

'

'

'

'

$0.25

$0.25

Series Four Preferred Units (in shares)

360,126

'

'

'

'

'

360,126

'

'

'

'

'

Series Four Preferred Units Annual Dividend Payable Rate

'

'

'

'

'

2.00%

2.00%

'

'

'

'

'

Preferred Units Liquidation Preference

'

'

$50

'

'

$50

$50

$50

'

'

'

'

Series Four Preferred Units Released from Escrow

'

'

'

'

'

'

'

'

'

319,687

'

'

Series Four Preferred Units Elected to Redeem

'

'

'

'

'

'

'

'

319,687

'

'

'

Noncontrolling_Interests_Commo

Noncontrolling Interests (Common Units) (Narrative) (Details) (USD $)	0 Months Ended		6 Months Ended
	Apr. 30, 2014	Jan. 29, 2014	Jun. 30, 2014	Jun. 19, 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)	'	'	66,612	'
Redemption of OP units issued on conversion of LTIP Units (in shares)	'	'	65,275	'
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	$0.65	'	'
Distribution paid to outperformance awards, OPP Units (in dollars per share)	$0.07	$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	'	'	$2,100,000,000	'
Closing price of common stock (in dollars per share)	'	'	$118.18	'
2012 OPP Units [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	'
2014 MYLTIP Units [Member]	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
2014 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	'
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]	'	'	'	'
Dividend payable date	'	'	30-Apr-14	'
Holders of record date	'	'	31-Mar-14	'
Quarter 2 2014 [Member]	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Dividend shareholder of record date	'	'	30-Jun-14	'
Dividends declared date	'	'	19-Jun-14	'
Dividend payable date	'	'	31-Jul-14	'
Quarter 2 2014 [Member] | OP Units [Member]	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Dividends declared date	'	'	19-Jun-14	'
Dividend payable date	'	'	31-Jul-14	'
Holders of record date	'	'	30-Jun-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	'	'
2011 OPP Unitsn [Member]	'	'	'	'
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]	'	'	'	'
Accelerated compensation expenses related to 2011 OPP Units	'	'	$1,200,000	'

Noncontrolling_Interests_Prope

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) (USD $)	6 Months Ended			0 Months Ended				0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Feb. 26, 2013	Feb. 07, 2013	31-May-13	Oct. 09, 2013	31-May-13	Feb. 26, 2013
				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]	Company [Member]
							sqft	partners	Salesforece Tower (formerly Transbay Tower) [Member]
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'	'
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	'	'
Fair value of capital recorded upon consolidation	0	483,488,000	'	'	'	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 (in sf)	'	'	'	'	'	'	1,246,000	'	'
Noncontrolling interests in property partnerships	$721,096,000	'	$726,132,000	'	'	'	'	'	'

Noncontrolling_Interests_Redee1

Noncontrolling Interests (Redeemable Preferred Units) (Details) (USD $)

3 Months Ended

6 Months Ended

In Thousands, except Share data, unless otherwise specified

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

12-May-14

Mar. 11, 2014

Redeemable Preferred Units [Member]

Redeemable Preferred Units [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Noncontrolling Interests [Member]

Series Two Preferred Units [Member]

Series Two Preferred Units [Member]

Series Two Preferred Units [Member]

Noncontrolling Interest [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Series Two Preferred Units (in shares)

'

'

'

'

'

'

'

'

666,116

666,116

'

Series Two Preferred Units On Converted Basis

'

'

'

'

'

'

'

'

874,168

874,168

874,168

Activity of noncontrolling interests

'

'

'

'

'

'

'

'

'

'

'

Beginning Balance

'

'

'

'

$105,746

$199,378

'

'

'

'

'

Net income

2,938

3,741

6,146

5,067

939

2,303

'

'

'

'

'

Distributions

'

'

'

'

-939

-2,303

'

'

'

'

'

Reallocation of partnership interest

'

'

'

'

-87,740

[1]

-444

-2,241

-10,309

'

'

'

Ending Balance

'

'

'

'

$18,006

$198,934

'

'

'

'

'

[1]

Includes the conversion of the remaining 666,116 Series Two Preferred Units into 874,168 OP Units during the six months ended June 30, 2014.

Noncontrolling_Interests_Nonco

Noncontrolling Interests (Noncontrolling Interests-Redeemable Common Units) (Details) (Noncontrolling Interests [Member], USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Noncontrolling Interests [Member]	'	'
Activity of noncontrolling interests	'	'
Beginning Balance	$1,710,218	$1,836,522
Contributions	23,990	26,384
Net income	15,010	57,177
Distributions	-22,673	-22,705
Conversion of redeemable partnership units	-2,241	-10,309
Unearned compensation	-11,091	-5,996
Accumulated other comprehensive loss	126	127
Adjustments to reflect redeemable partnership units at redemption value	410,333	-66,718
Ending Balance	$2,123,672	$1,814,482

Noncontrolling_Interests_Nonco1

Noncontrolling Interests (Noncontrolling Interests-Property Partnerships) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Activity of noncontrolling interests	'	'	'	'
Beginning balance	'	'	$726,132	'
Fair value of capital recorded upon consolidation	'	'	0	483,488
Capital contributions	'	'	1,675	6,018
Net Income (loss)	7,553	-219	11,907	2,355
Ending balance	721,096	'	721,096	'
Property Partnerships [Member]	'	'	'	'
Activity of noncontrolling interests	'	'	'	'
Beginning balance	'	'	726,132	-1,964
Fair value of capital recorded upon consolidation	'	'	'	483,488
Capital contributions	'	'	1,675	10,564
Net Income (loss)	'	'	5,438	-1,199
Distributions	'	'	-12,149	-1,500
Ending balance	$721,096	$489,389	$721,096	$489,389

Noncontrolling_Interests_Redee2

Noncontrolling Interests Redeemable Interest in Property Partnerships (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014		Jun. 30, 2013
Redeemable Interest in Property Partnership [Abstract]	'	'		'
Quantifying Misstatement in Current Year Financial Statements, Amount	($2,400,000)	'		'
Beginning Balance	'	99,609,000		97,558,000
Net loss	'	-240,000		-980,000
Distributions	'	-2,300,000		-2,950,000
Adjustment to reflect redeemable interest at redemption value	'	6,709,000	[1]	4,534,000
Ending Balance	$103,778,000	$103,778,000		$98,162,000
[1]	Includes an out-of-period adjustment totaling approximately $2.4 million (See Note 2).

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

6 Months Ended

0 Months Ended

6 Months Ended

0 Months Ended

6 Months Ended

6 Months Ended

Apr. 30, 2014

Jan. 29, 2014

Jun. 30, 2014

Jun. 30, 2013

Jun. 19, 2014

Dec. 31, 2013

Jun. 03, 2014

Jun. 30, 2014

Jun. 02, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

15-May-14

Feb. 18, 2014

Jun. 30, 2014

Jun. 19, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Mar. 27, 2018

Jun. 30, 2014

Mar. 27, 2018

New ATM program [Member]

New ATM program [Member]

ATM Program [Member]

Quarter 4 2013 [Member]

Quarter 1 2014 [Member]

Quarter 2 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]

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]

Subsequent Event [Member]

Y

Quarter 1 2014 [Member]

Quarter 2 2014 [Member]

Quarter 3 2014 [Member]

Series B Cumulative Redeemable Preferred Stock [Member]

Class of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

General partnership units (in units)

'

'

1,710,624

'

'

1,700,222

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Limited partnership units (in units)

'

'

151,381,950

'

'

151,282,879

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

$600,000,000

'

$600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

At Market Stock Offering Program Maximum Length Of Sale In Years

'

'

'

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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)

'

'

66,612

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

OP Units to Boston Properties, Inc. in connection with the exercise by certain employees of options to purchase Common Stock of Boston Properties, Inc

'

'

17,124

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividend payable date

'

'

'

'

'

'

'

'

'

29-Jan-14

30-Apr-14

31-Jul-14

'

'

'

'

'

18-Feb-14

15-May-14

15-Aug-14

'

'

'

Dividend paid on common stock (in dollars per share)

$0.65

$2.90

'

'

'

'

'

'

'

'

'

'

$32.81

$32.81

'

'

'

'

'

'

'

'

'

Dividend shareholder of record date

'

'

'

'

'

'

'

'

'

31-Dec-13

31-Mar-14

30-Jun-14

'

'

'

'

'

'

'

5-Aug-14

'

'

'

Dividends payable, date declared

'

'

'

'

'

'

'

'

'

'

'

19-Jun-14

'

'

'

'

'

'

'

19-Jun-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

'

'

'

$25

$25

$2,500

Proceeds from Issuance of Series B Preferred Stock

'

'

0

193,920,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ratio of depository shares to shares of Series B Preferred Stock

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.01

'

'

'

'

'

'

'

'

Series B, Dividend Rate, Percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.25%

'

'

'

'

'

'

'

'

Common Stock, Value, Issued

'

'

'

'

'

'

'

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Earnings_Per_Common_Unit_Detai

Earnings Per Common Unit (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Income (Loss) from Continuing Operations Attributable to Parent	'	$501,874	'	$542,419
Redeemable common units (in shares)	17,304,000	16,995,000	17,059,000	17,049,000
Basic Earnings:	'	'	'	'
Net income attributable to Boston Properties Limited Partnership, Units (Denominator) (in shares)	170,382,000	168,933,000	170,113,000	168,842,000
Inceom (loss) from continuing operations before discontinued operations and allocation of undistributed earnings (dollars per share)	'	$2.97	'	$3.21
Discontinued operations attributable to Boston Properties Limited Partnership, Income (Numerator)	'	3,315	'	23,693
Discontinued Operations (in shares)	'	0	'	0
Discontinued operations attributable to Boston Properties Limited Partnership, Per Unit Amount (in dollars per share)	$0	$0.02	$0	$0.14
Net income attributable to Boston Properties Limited Partnership	87,436	505,189	149,655	566,112
Allocation of undistributed earnings to participating securities (numerator)	'	-4,035	'	-3,536
Allocation of undistributed earnings to participating securities (in shares)	'	0	'	0
Allocation of undistributed earnings to participating securities (in dollars per shares)	'	($0.02)	'	($0.02)
Net income attributable to Boston Properties Limited Partnership	'	501,154	'	562,576
Net income (in dollars per share)	$0.51	$2.97	$0.88	$3.33
Effect of Dilutive Securities:	'	'	'	'
Stock Based Compensation and Exchangeable Senior Notes, Income (Numerator)	0	0	0	0
Stock Based Compensation and Exchangeable Senior Notes, Units (Denominator) (in shares)	160,000	552,000	149,000	429,000
Stock Based Compensation and Exchangeable Senior Notes, Per Unit Amount (in dollars per share)	$0	($0.01)	$0	($0.01)
Diluted Earnings:	'	'	'	'
Diluted Earnings: Net income attributable to Boston Properties Limited Partnership	$87,436	$501,154	$149,655	$562,576
Diluted Earnings: Net income, Units (Denominator) (in shares)	170,542,000	169,485,000	170,262,000	169,271,000
Diluted Earnings: Net income, Per Unit Amount (in dollars per share)	$0.51	$2.96	$0.88	$3.32

Stock_Option_and_Incentive_Pla1

Stock Option and Incentive Plan (Restricted Stock) (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
stock based compensation expense	$6,200,000	$6,400,000	$16,000,000	$31,900,000
Restricted Stock [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
Shares issued (in shares)	23,968	'	23,968	'
Employee and director payment per share (in dollars per share)	'	'	$0.01	'
Common Stock, Value, Issued	2,600,000	'	2,600,000	'
Employee's weighted average cost per share (in dollars per share)	$109.27	'	$109.27	'
LTIP Units [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
LTIP units issued (in shares)	127,094	'	127,094	'
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	'	'	12,800,000	'
Per unit fair value weighted-average (in dollars per share)	$100.61	'	$100.61	'
2011 OPP Unitsn [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
Accelerated compensation expenses related to 2011 OPP Units	'	'	1,200,000	'
MYLTIP [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
MYLTIP units issued (in shares)	485,459	'	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	22,300,000	'	22,300,000	'
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 2012 OPP Units and 2013 and 2014 MYLTIP Units [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
Unrecognized compensation expenses	18,600,000	'	18,600,000	'
Weighted-average period (in years)	'3 years 1 month 6 days	'	'	'
Board of Directors Chairman [Member]	'	'	'	'
Stock Option And Incentive Plan And Stock Purchase Plan [Line Items]	'	'	'	'
stock based compensation expense	'	$1,600,000	'	$18,600,000

Stock_Option_and_Incentive_Pla2

Stock Option and Incentive Plan Stock option and incentive plan (Narrative) (Details) (2014 MYLTIP Units [Member], USD $)	0 Months Ended
	Jan. 27, 2014
	indices
	tiers
	Y
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
TRS Measurement, Years	3
Indices Used to Compare TRS	2
Number of Tiers	4
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%
Distributions Percent Before Measurement Date	10.00%
Value of MYLTIP Awards	$12,700,000
MYLTIP Value Amortized Into Earnings, Years	4
Cohen & Steers Realty Majors Portfolio Index [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Weighted Percentage of Index Used to Compare to TRS	50.00%
NAREIT Office Index adjusted [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Weighted Percentage of Index Used to Compare to TRS	50.00%
Minimum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Potential Awards Earned	0
Maximum [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Potential Awards Earned	40,200,000
Threshold [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Amount of Each Tier	6,700,000
Target [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Amount of Each Tier	13,400,000
Exceptional [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Amount of Each Tier	40,200,000
High [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Amount of Each Tier	$26,800,000
MYLTIP Vesting 2017 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Vesting Percentage	50.00%
Vesting Date	3-Feb-17
MYLTIP vesting two thousand eighteen [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Vesting Percentage	50.00%
Vesting Date	3-Feb-18

Segment_Information_Schedule_O

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Rental Revenue: Class A Office	$548,699	$470,680	$1,088,605	$916,057
Rental Revenue: Office/Technical	15,924	14,896	31,621	24,743
Rental Revenue: Residential	6,298	5,484	11,980	11,062
Rental Revenue: Hotel	12,367	11,118	20,560	19,409
Rental Revenue Total	583,288	502,178	1,152,766	971,271
Total revenue	589,794	510,033	1,164,488	987,859
Rental Revenue: % of Grand Totals	100.00%	100.00%	100.00%	100.00%
Rental Expenses: Class A Office	194,543	169,418	393,064	332,921
Rental Expenses: Office/Technical	4,167	3,770	8,272	6,596
Rental Expenses: Residential	3,936	2,830	7,698	5,563
Rental Expenses: Hotel	7,315	7,335	14,112	14,379
Rental Expenses: Total	209,961	183,353	423,146	359,459
Rental Expenses: % Of Grand Totals	100.00%	100.00%	100.00%	100.00%
Net operating income	373,327	318,825	729,620	611,812
Percentage Of Total Net Operating Income	100.00%	100.00%	100.00%	100.00%
Boston [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Rental Revenue: Class A Office	173,128	164,137	344,070	324,961
Rental Revenue: Office/Technical	5,912	5,538	11,732	11,191
Rental Revenue: Residential	1,089	1,065	2,252	2,132
Rental Revenue: Hotel	12,367	11,118	20,560	19,409
Rental Revenue Total	192,496	181,858	378,614	357,693
Rental Revenue: % of Grand Totals	33.00%	36.21%	32.84%	36.83%
Rental Expenses: Class A Office	65,818	62,693	137,216	127,979
Rental Expenses: Office/Technical	1,736	1,627	3,425	3,414
Rental Expenses: Residential	544	407	992	850
Rental Expenses: Hotel	7,315	7,335	14,112	14,379
Rental Expenses: Total	75,413	72,062	155,745	146,622
Rental Expenses: % Of Grand Totals	35.92%	39.30%	36.81%	40.79%
Net operating income	117,083	109,796	222,869	211,071
Percentage Of Total Net Operating Income	31.36%	34.44%	30.55%	34.50%
New York [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Rental Revenue: Class A Office	223,899	158,158	441,207	296,681
Rental Revenue: Office/Technical	0	0	0	0
Rental Revenue: Residential	0	0	0	0
Rental Revenue: Hotel	0	0	0	0
Rental Revenue Total	223,899	158,158	441,207	296,681
Rental Revenue: % of Grand Totals	38.39%	31.49%	38.28%	30.54%
Rental Expenses: Class A Office	74,962	55,357	149,333	104,445
Rental Expenses: Office/Technical	0	0	0	0
Rental Expenses: Residential	0	0	0	0
Rental Expenses: Hotel	0	0	0	0
Rental Expenses: Total	74,962	55,357	149,333	104,445
Rental Expenses: % Of Grand Totals	35.70%	30.19%	35.29%	29.06%
Net operating income	148,937	102,801	291,874	192,236
Percentage Of Total Net Operating Income	39.89%	32.24%	40.00%	31.42%
San Francisco [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Rental Revenue: Class A Office	57,450	53,331	112,058	106,002
Rental Revenue: Office/Technical	6,341	5,327	12,558	5,478
Rental Revenue: Residential	0	0	0	0
Rental Revenue: Hotel	0	0	0	0
Rental Revenue Total	63,791	58,658	124,616	111,480
Rental Revenue: % of Grand Totals	10.94%	11.68%	10.81%	11.48%
Rental Expenses: Class A Office	21,282	19,657	40,595	38,030
Rental Expenses: Office/Technical	1,308	1,116	2,522	1,151
Rental Expenses: Residential	0	0	0	0
Rental Expenses: Hotel	0	0	0	0
Rental Expenses: Total	22,590	20,773	43,117	39,181
Rental Expenses: % Of Grand Totals	10.76%	11.33%	10.19%	10.90%
Net operating income	41,201	37,885	81,499	72,299
Percentage Of Total Net Operating Income	11.04%	11.88%	11.17%	11.82%
Washington, DC [Member]	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Rental Revenue: Class A Office	94,222	95,054	191,270	188,413
Rental Revenue: Office/Technical	3,671	4,031	7,331	8,074
Rental Revenue: Residential	5,209	4,419	9,728	8,930
Rental Revenue: Hotel	0	0	0	0
Rental Revenue Total	103,102	103,504	208,329	205,417
Rental Revenue: % of Grand Totals	17.67%	20.62%	18.07%	21.15%
Rental Expenses: Class A Office	32,481	31,711	65,920	62,467
Rental Expenses: Office/Technical	1,123	1,027	2,325	2,031
Rental Expenses: Residential	3,392	2,423	6,706	4,713
Rental Expenses: Hotel	0	0	0	0
Rental Expenses: Total	36,996	35,161	74,951	69,211
Rental Expenses: % Of Grand Totals	17.62%	19.18%	17.71%	19.25%
Net operating income	$66,106	$68,343	$133,378	$136,206
Percentage Of Total Net Operating Income	17.71%	21.44%	18.28%	22.26%

Segment_Information_Schedule_O1

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership	'	'	'	'
Net Operating Income	$203,299	$170,323	$382,221	$304,274
Development and management services income	6,506	7,855	11,722	16,588
Income from unconsolidated joint ventures	2,834	48,783	5,650	57,504
Gain on consolidation of joint ventures	0	387,801	0	387,801
Interest and other income	2,109	1,296	3,420	2,767
Gains (Losses) from investments in securities	662	181	948	916
Gains from early extinguishments of debt	0	152	0	152
Gain on forgiveness of debt from discontinued operations	0	0	0	20,736
General and administrative expense	23,271	24,316	53,176	69,832
Transaction costs	661	535	1,098	978
Depreciation and amortization expense	152,602	131,506	304,847	248,915
Interest expense	110,977	103,140	224,531	203,573
Impairment loss	0	0	0	4,401
Impairment loss from discontinued operations	0	0	0	2,852
Noncontrolling interest in property partnerships	7,553	-219	11,907	2,355
Noncontrolling interest-redeemable preferred units	2,938	3,741	6,146	5,067
Net income attributable to Boston Properties Limited Partnership	87,436	505,189	149,655	566,112
Intersegment Eliminations [Member]	'	'	'	'
Reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership	'	'	'	'
Net Operating Income	373,327	318,825	729,620	611,812
Development and management services income	6,506	7,855	11,722	16,588
Income from unconsolidated joint ventures	2,834	48,783	5,650	57,504
Gain on consolidation of joint ventures	0	387,801	0	387,801
Interest and other income	2,109	1,296	3,420	2,767
Gains (Losses) from investments in securities	662	181	948	916
Gains from early extinguishments of debt	0	152	0	152
Income from discontinued operations	0	3,315	0	5,809
Gain on forgiveness of debt from discontinued operations	0	0	0	20,736
General and administrative expense	23,271	24,316	53,176	69,832
Transaction costs	661	535	1,098	978
Depreciation and amortization expense	152,602	131,506	304,847	248,915
Interest expense	110,977	103,140	224,531	203,573
Impairment loss	0	0	0	4,401
Impairment loss from discontinued operations	0	0	0	2,852
Noncontrolling interest in property partnerships	7,553	-219	11,907	2,355
Noncontrolling interest-redeemable preferred units	2,938	3,741	6,146	5,067
Net income attributable to Boston Properties Limited Partnership	$87,436	$505,189	$149,655	$566,112

Segment_Information_Segment_In

Segment Information Segment Information (narrative) (Details) (USD $)	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013	31-May-13
			Princeton [Member]	Princeton [Member]	San Francisco [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	$2.10	$4	$0.50	$0.90	$1.60	$3.10	'
Number of Joint Venture Partners	'	'	'	'	'	'	2

Subsequent_Events_Subsequent_E

Subsequent Events Subsequent Events (Details) (USD $)	6 Months Ended					0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2014	Jul. 03, 2014	Jul. 01, 2014	Jul. 23, 2014	Jul. 29, 2014	Jul. 29, 2014	Jul. 29, 2014
			Noncontrolling Interests [Member]	series four preferred units [Member]	series four preferred units [Member]	New Dominion Technology Park, Bldg. Two [Member]	Broad Run Business Park [Member]	Mountain View Technology Park and Mountain View Research Building Sixteen [Member]	Mountain View Research Building Sixteen [Member]	Mountain View Technology [Member]
				Noncontrolling Interests [Member]			acre		Mountain View Technology Park and Mountain View Research Building Sixteen [Member]	Mountain View Technology Park and Mountain View Research Building Sixteen [Member]
									sqft	sqft
										Buildings
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'	'
Repayments of Secured Debt	$12,207,000	$79,865,000	'	'	'	$63,000,000	'	'	'	'
Coupon/Stated Rate (percent)	'	'	'	'	'	5.55%	'	'	'	'
Maturity Date	'	'	'	'	'	1-Oct-14	'	'	'	'
Series Four Preferred Units Redeemed (in shares)	'	'	'	'	319,687	'	'	'	'	'
Redemption of Series Four Preferred Units	'	'	'	'	16,000,000	'	'	'	'	'
Series Four Preferred Units (in shares)	'	'	360,126	360,126	40,440	'	'	'	'	'
Net Rentable Area (in sf)	'	'	'	'	'	'	'	'	63,000	135,000
Contractual Sales Price	'	'	'	'	'	'	$9,800,000	$92,100,000	'	'
Number of real estate properties	'	'	'	'	'	'	'	'	'	7
Land Subject to Ground Leases	'	'	'	'	'	'	15.5	'	'	'