Boston Properties (BXP) 10-Q 6 May 16 2016 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 02, 2016
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Entity Registrant Name	BOSTON PROPERTIES INC
Amendment Flag	false
Entity Central Index Key	1,037,540
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		153,611,330
Boston Properties Limited Partnership
Entity Information [Line Items]
Document Type	10-Q
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Entity Registrant Name	BOSTON PROPERTIES LTD PARTNERSHIP
Amendment Flag	false
Entity Central Index Key	1,043,121
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 ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Real estate, at cost (amounts includes variable interest entities (“VIEs”) at March 31, 2016)	$ 18,424,542	$ 18,465,405
Construction in progress (amounts related to VIEs of $486,025 at March 31, 2016)	857,578	763,935
Land held for future development	256,952	252,195
Less: accumulated depreciation (includes amounts related to VIEs at March 31, 2016)	(3,969,648)	(3,925,894)
Total real estate	15,569,424	15,555,641
Cash and cash equivalents (amounts related to VIEs of $227,255 at March 31, 2016)	1,605,678	723,718
Cash held in escrows (amounts related to VIEs of $3,671 at March 31, 2016)	71,349	73,790
Investments in securities	21,077	20,380
Tenant and other receivables (amounts related to VIEs of $24,403 at March 31, 2016)	73,759	97,865
Accrued rental income (amounts related to VIEs of $217,148 at March 31, 2016)	767,864	754,883
Deferred charges, net (amounts related to VIEs of $323,493 at March 31, 2016)	693,976	704,867
Prepaid expenses and other assets (amounts related to VIEs of $77,995 at March 31, 2016)	136,799	185,118
Investments in unconsolidated joint ventures	235,904	235,224
Total assets	19,175,830	18,351,486
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,060,838 at March 31, 2016)	3,416,622	3,435,242
Unsecured senior notes, net	6,255,602	5,264,819
Unsecured line of credit	0	0
Mezzanine notes payable (amounts related to VIEs of $308,142 at March 31, 2016)	308,142	308,482
Outside members' notes payable (amounts related to VIEs of $180,000 at March 31, 2016)	180,000	180,000
Accounts payable and accrued expenses (amounts related to VIEs of $82,270 at March 31, 2016)	252,727	274,709
Dividends and distributions payable	113,079	327,320
Accrued interest payable (amounts related to VIEs of $136,165 at March 31, 2016)	221,578	190,386
Other liabilities (amounts related to VIEs of $205,007 at March 31, 2016)	498,290	483,601
Total liabilities	11,246,040	10,464,559
Commitments and contingencies	0	0
Equity / Capital
Excess stock, $0.01 par value, 150,000,000 shares authorized, none issued or outstanding	0	0
Preferred stock, $.01 par value, 50,000,000 shares authorized
5.25% Series B cumulative redeemable preferred stock / unit liquidation preference $2,500 per share / unit, 92,000 shares / units authorized, 80,000 shares / units issued and outstanding at March 31, 2016 and December 31, 2015	200,000	200,000
Common stock, $0.01 par value, 250,000,000 shares authorized, 153,683,866 and 153,658,866 issued and 153,604,966 and 153,579,966 outstanding at March 31, 2016 and December 31, 2015, respectively	1,536	1,536
Additional paid-in capital	6,306,723	6,305,687
Dividends in excess of earnings	(699,048)	(780,952)
Treasury common stock at cost, 78,900 shares at March 31, 2016 and December 31, 2015	(2,722)	(2,722)
Accumulated other comprehensive loss	(56,706)	(14,114)
Total stockholders’ equity attributable to Boston Properties, Inc.	5,749,783	5,709,435
Noncontrolling interests:
Common units of the Operating Partnership	616,095	603,092
Property partnerships	1,563,912	1,574,400
Total equity	7,929,790	7,886,927
Total liabilities and equity / capital	19,175,830	18,351,486
Boston Properties Limited Partnership
ASSETS
Real estate, at cost (amounts includes variable interest entities (“VIEs”) at March 31, 2016)	18,006,818	18,045,011
Construction in progress (amounts related to VIEs of $486,025 at March 31, 2016)	857,578	763,935
Land held for future development	256,952	252,195
Less: accumulated depreciation (includes amounts related to VIEs at March 31, 2016)	(3,889,084)	(3,846,816)
Total real estate	15,232,264	15,214,325
Cash and cash equivalents (amounts related to VIEs of $227,255 at March 31, 2016)	1,605,678	723,718
Cash held in escrows (amounts related to VIEs of $3,671 at March 31, 2016)	71,349	73,790
Investments in securities	21,077	20,380
Tenant and other receivables (amounts related to VIEs of $24,403 at March 31, 2016)	73,759	97,865
Accrued rental income (amounts related to VIEs of $217,148 at March 31, 2016)	767,864	754,883
Deferred charges, net (amounts related to VIEs of $323,493 at March 31, 2016)	693,976	704,867
Prepaid expenses and other assets (amounts related to VIEs of $77,995 at March 31, 2016)	136,799	185,118
Investments in unconsolidated joint ventures	235,904	235,224
Total assets	18,838,670	18,010,170
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,060,838 at March 31, 2016)	3,416,622	3,435,242
Unsecured senior notes, net	6,255,602	5,264,819
Unsecured line of credit	0	0
Mezzanine notes payable (amounts related to VIEs of $308,142 at March 31, 2016)	308,142	308,482
Outside members' notes payable (amounts related to VIEs of $180,000 at March 31, 2016)	180,000	180,000
Accounts payable and accrued expenses (amounts related to VIEs of $82,270 at March 31, 2016)	252,727	274,709
Dividends and distributions payable	113,079	327,320
Accrued interest payable (amounts related to VIEs of $136,165 at March 31, 2016)	221,578	190,386
Other liabilities (amounts related to VIEs of $205,007 at March 31, 2016)	498,290	483,601
Total liabilities	11,246,040	10,464,559
Commitments and contingencies	0	0
Noncontrolling interest:
Redeemable partnership units—16,092,449 and 16,097,473 common units and 2,065,185 and 1,831,714 long term incentive units outstanding at redemption value at March 31, 2016 and December 31, 2015, respectively	2,307,472	2,286,689
Redeemable interest in property partnership	1,563,912	1,574,400
Preferred stock, $.01 par value, 50,000,000 shares authorized
5.25% Series B cumulative redeemable preferred stock / unit liquidation preference $2,500 per share / unit, 92,000 shares / units authorized, 80,000 shares / units issued and outstanding at March 31, 2016 and December 31, 2015	193,623	193,623
Accumulated other comprehensive loss	(65,830)	(18,337)
Noncontrolling interests:
Boston Properties Limited Partnership partners’ capital—1,717,626 and 1,715,092 general partner units and 151,887,340 and 151,864,874 limited partner units outstanding at March 31, 2016 and December 31, 2015, respectively	3,527,623	3,490,899
Total equity	5,285,158	5,258,922
Total liabilities and equity / capital	$ 18,838,670	$ 18,010,170

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Excess stock, par value	$ 0.01	$ 0.01
Excess stock, shares authorized	150,000,000	150,000,000
Excess stock, shares issued	0	0
Excess stock, shares outstanding	0	0
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	153,683,866	153,658,866
Common stock, shares outstanding	153,604,966	153,579,966
Treasury common stock at cost, shares	78,900	78,900
Real Estate Investment Property, at Cost	$ 18,424,542	$ 18,465,405
Construction in Progress	857,578	763,935
Accumulated depreciation	3,969,648	3,925,894
Cash and Cash Equivalents	1,605,678	723,718
Restricted Cash and Cash Equivalents	71,349	73,790
Accounts Receivable, Net	73,759	97,865
Deferred Rent Receivables, Net	767,864	754,883
Deferred Charges, net	693,976	704,867
Prepaid expense and other assets	136,799	185,118
Mortgage notes payable, net	3,416,622	3,435,242
Mezzanine notes payable	308,142	308,482
Outside member's notes payable	180,000	180,000
Accounts Payable and Accrued Liabilities	252,727	274,709
Interest Payable	221,578	190,386
Other Liabilities	$ 498,290	$ 483,601
Series B Cumulative Redeemable Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	92,000	92,000
Series B Dividend Rate Percentage	5.25%	5.25%
Series B, Liquidation Preference Per Share (dollars per share)	$ 2,500	$ 2,500
Series B, shares issued	80,000	80,000
Series B, Shares Outstanding (in shares)	80,000	80,000
Boston Properties Limited Partnership
NonControlling Interest Redeemable Partnership Units Common Units Shares Outstanding	16,092,449	16,097,473
NonControlling Interest Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Shares Outstanding	2,065,185	1,831,714
General Partners' Capital Account, Units Outstanding	1,717,626	1,715,092
Limited Partners' Capital Account, Units Outstanding	151,887,340	151,864,874
Real Estate Investment Property, at Cost	$ 18,006,818	$ 18,045,011
Construction in Progress	857,578	763,935
Accumulated depreciation	3,889,084	3,846,816
Cash and Cash Equivalents	1,605,678	723,718
Restricted Cash and Cash Equivalents	71,349	73,790
Accounts Receivable, Net	73,759	97,865
Deferred Rent Receivables, Net	767,864	754,883
Deferred Charges, net	693,976	704,867
Prepaid expense and other assets	136,799	185,118
Mortgage notes payable, net	3,416,622	3,435,242
Mezzanine notes payable	308,142	308,482
Outside member's notes payable	180,000	180,000
Accounts Payable and Accrued Liabilities	252,727	274,709
Interest Payable	221,578	190,386
Other Liabilities	$ 498,290	$ 483,601
Boston Properties Limited Partnership | Series B Cumulative Redeemable Preferred Stock [Member]
Series B Dividend Rate Percentage	5.25%	5.25%
Series B, Liquidation Preference Per Share (dollars per share)	$ 2,500	$ 2,500
Series B, shares issued	80,000	80,000
Series B, Shares Outstanding (in shares)	80,000	80,000
VIE
Real Estate Investment Property, at Cost	$ 6,024,005
Construction in Progress	486,025
Accumulated depreciation	(690,415)
Cash and Cash Equivalents	227,255
Restricted Cash and Cash Equivalents	3,671
Accounts Receivable, Net	24,403
Deferred Rent Receivables, Net	217,148
Deferred Charges, net	323,493
Prepaid expense and other assets	77,995
Mortgage notes payable, net	2,060,838
Mezzanine notes payable	308,142
Outside member's notes payable	180,000
Accounts Payable and Accrued Liabilities	82,270
Interest Payable	136,165
Other Liabilities	205,007
VIE | Boston Properties Limited Partnership
Real Estate Investment Property, at Cost	5,944,607
Construction in Progress	486,025
Accumulated depreciation	(675,124)
Cash and Cash Equivalents	227,255
Restricted Cash and Cash Equivalents	3,671
Accounts Receivable, Net	24,403
Deferred Rent Receivables, Net	217,148
Deferred Charges, net	323,493
Prepaid expense and other assets	77,995
Mortgage notes payable, net	2,060,838
Mezzanine notes payable	308,142
Outside member's notes payable	180,000
Accounts Payable and Accrued Liabilities	82,270
Interest Payable	136,165
Other Liabilities	$ 205,007

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenue
Base rent	$ 536,128	$ 490,682
Recoveries from tenants	89,586	88,593
Parking and other	24,825	24,788
Total rental revenue	650,539	604,063
Hotel revenue	8,757	9,085
Development and management services	6,689	5,328
Total revenue	665,985	618,476
Expenses
Rental	219,172	221,350
Hotel	7,634	7,576
General and administrative	29,353	28,791
Transaction costs	25	327
Depreciation and amortization	159,448	154,223
Total expenses	415,632	412,267
Operating income	250,353	206,209
Other income (expense)
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
Interest expense	(105,309)	(108,757)
Income before gains on sales of real estate	148,599	114,086
Gains on sales of real estate	67,623	95,084
Net income	216,222	209,170
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships	(10,464)	(15,208)
Noncontrolling interest—redeemable preferred units	0	(3)
Noncontrolling interest—common units of the Operating Partnership	(21,393)	(20,188)
Net income attributable to the Company	184,365	173,771
Preferred dividends / distributions	(2,618)	(2,589)
Net income attributable to the Company's common shareholders / unitholders	$ 181,747	$ 171,182
Basic earnings per common share / unit attributable to the Company's common shareholders / unitholders
Net income (in dollars per share / unit)	$ 1.18	$ 1.12
Weighted average number of common shares / units outstanding	153,626	153,230
Diluted earnings per common share / unit attributable to the Company's common shareholders / unitholders
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 1.18	$ 1.11
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)	153,917	153,873
Boston Properties Limited Partnership
Revenue
Base rent	$ 536,128	$ 490,682
Recoveries from tenants	89,586	88,593
Parking and other	24,825	24,788
Total rental revenue	650,539	604,063
Hotel revenue	8,757	9,085
Development and management services	6,689	5,328
Total revenue	665,985	618,476
Expenses
Rental	219,172	221,350
Hotel	7,634	7,576
General and administrative	29,353	28,791
Transaction costs	25	327
Depreciation and amortization	157,461	152,224
Total expenses	413,645	410,268
Operating income	252,340	208,208
Other income (expense)
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
Interest expense	(105,309)	(108,757)
Income before gains on sales of real estate	150,586	116,085
Gains on sales of real estate	69,792	95,084
Net income	220,378	211,169
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships	(10,464)	(15,208)
Noncontrolling interest—redeemable preferred units	0	(3)
Net income attributable to the Company	209,914	195,958
Preferred dividends / distributions	(2,618)	(2,589)
Net income attributable to the Company's common shareholders / unitholders	$ 207,296	$ 193,369
Basic earnings per common share / unit attributable to the Company's common shareholders / unitholders
Net income (in dollars per share / unit)	$ 1.21	$ 1.13
Weighted average number of common shares / units outstanding	171,309	171,084
Diluted earnings per common share / unit attributable to the Company's common shareholders / unitholders
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 1.21	$ 1.12
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)	171,600	171,727

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Net income		$ 216,222	$ 209,170
Other comprehensive loss:
Effective portion of interest rate contracts		(58,646)	(3,533)
Amortization of interest rate contracts	[1],[2]	627	627
Other comprehensive loss		(58,019)	(2,906)
Comprehensive income		158,203	206,264
Net income attributable to noncontrolling interests		(31,857)	(35,399)
Other comprehensive (income) loss attributable to noncontrolling interests		15,427	303
Comprehensive income attributable to the Company		141,773	171,168
Boston Properties Limited Partnership
Net income		220,378	211,169
Other comprehensive loss:
Effective portion of interest rate contracts		(58,646)	(3,533)
Amortization of interest rate contracts	[2],[3]	627	627
Other comprehensive loss		(58,019)	(2,906)
Comprehensive income		162,359	208,263
Net income attributable to noncontrolling interests		62	(15,211)
Comprehensive income attributable to the Company		$ 162,421	$ 193,052
[1]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties, Inc.’s Consolidated Statements of Operations.
[2]	Consists of amounts from previous interest rate hedging programs entered into prior to 2015.
[3]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties Limited Partnership's Consolidated Statements of Operations.

Consolidated Statements Of Stoc

Consolidated Statements Of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-In Capital [Member]	Dividends In Excess Of Earnings [Member]	Treasury Stock, At Cost [Member]	Accumulated Other Comprehensive (Income) Loss [Member]	Noncontrolling Interests [Member]
Equity, value at Dec. 31, 2014	$ 7,902,936	$ 1,531	$ 200,000	$ 6,270,257	$ (762,464)	$ (2,722)	$ (9,304)	$ 2,205,638
Equity, shares at Dec. 31, 2014		153,114,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of operating partnership units to Common Stock, shares		259,000
Conversion of operating partnership units to Common Stock, value	0	$ 3		8,686				(8,689)
Allocated net income for the year	206,939				173,771			33,168
Dividends/distributions declared	(114,005)				(102,300)
Dividends/distributions declared								(11,705)
Shares issued pursuant to stock purchase plan, shares		2,000
Shares issued pursuant to stock purchase plan, value	313			313
Net activity from stock option and incentive plan, shares		27,000
Net activity from stock option and incentive plan, value	21,616	$ 0		1,842				19,774
Contributions from noncontrolling interests in property partnerships	629							629
Distributions to noncontrolling interests in property partnerships	(16,574)							(16,574)
Effective portion of interest rate contracts	(3,533)						(3,165)	(368)
Amortization of interest rate contracts	627						562	65
Reallocation of noncontrolling interest	0			5,162				(5,162)
Equity, value at Mar. 31, 2015	7,998,948	$ 1,534	200,000	6,286,260	(690,993)	(2,722)	(11,907)	2,216,776
Equity, shares at Mar. 31, 2015		153,402,000
Equity, value at Dec. 31, 2015	$ 7,886,927	$ 1,536	200,000	6,305,687	(780,952)	(2,722)	(14,114)	2,177,492
Equity, shares at Dec. 31, 2015	153,579,966	153,580,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of operating partnership units to Common Stock, shares		13,000
Conversion of operating partnership units to Common Stock, value		$ 0		446				(446)
Allocated net income for the year	$ 216,222				184,365			31,857
Dividends/distributions declared	(114,326)				(102,461)
Dividends/distributions declared								(11,865)
Shares issued pursuant to stock purchase plan, shares		3,000
Shares issued pursuant to stock purchase plan, value	332			332
Net activity from stock option and incentive plan, shares		9,000
Net activity from stock option and incentive plan, value	9,080			696				8,384
Contributions from noncontrolling interests in property partnerships	2,489							2,489
Distributions to noncontrolling interests in property partnerships	(12,915)							(12,915)
Effective portion of interest rate contracts	(58,646)						(43,154)	(15,492)
Amortization of interest rate contracts	627						562	65
Reallocation of noncontrolling interest				(438)				438
Equity, value at Mar. 31, 2016	$ 7,929,790	$ 1,536	$ 200,000	$ 6,306,723	$ (699,048)	$ (2,722)	$ (56,706)	$ 2,180,007
Equity, shares at Mar. 31, 2016	153,604,966	153,605,000

Consolidated Statement of Partn

Consolidated Statement of Partners' Capital Statement $ in Thousands	Boston Properties Limited PartnershipUSD ($)
Beginning Balance at Dec. 31, 2014	$ 3,639,916
Contributions	3,763
Net income allocable to general and limited partner units	175,770
Distributions	(102,300)
Accumulated other comprehensive loss	(2,603)
Unearned compensation	(1,608)
Conversion of redeemable partnership units	8,689
Adjustment to reflect redeemable partnership units at redemption value	(211,747)
Ending Balance at Mar. 31, 2015	3,509,880
Beginning Balance at Dec. 31, 2015	3,684,522
Contributions	1,165
Net income allocable to general and limited partner units	188,521
Distributions	(102,461)
Accumulated other comprehensive loss	(42,592)
Unearned compensation	(137)
Conversion of redeemable partnership units	446
Adjustment to reflect redeemable partnership units at redemption value	(8,218)
Ending Balance at Mar. 31, 2016	$ 3,721,246

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 216,222	$ 209,170
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	159,448	154,223
Non-cash compensation expense	10,069	11,011
Income from unconsolidated joint ventures	(1,791)	(14,834)
Distributions of net cash flow from operations of unconsolidated joint ventures	10,718	1,350
Gains from investments in securities	(259)	(393)
Non-cash portion of interest expense	(10,138)	(10,884)
Gains on sales of real estate	(67,623)	(95,084)
Change in assets and liabilities:
Cash held in escrows	1,940	1,044
Tenant and other receivables, net	25,018	(1,173)
Accrued rental income, net	(12,981)	(23,250)
Prepaid expenses and other assets	45,560	3,447
Accounts payable and accrued expenses	(5,209)	(5,535)
Accrued interest payable	31,192	23,098
Other liabilities	(33,319)	(23,136)
Tenant leasing costs	(19,867)	(27,608)
Total adjustments	132,758	(7,724)
Net cash provided by operating activities	348,980	201,446
Cash flows from investing activities:
Construction in progress	(122,940)	(60,013)
Building and other capital improvements	(25,329)	(19,391)
Tenant improvements	(55,739)	(26,950)
Proceeds from sales of real estate	104,816	194,821
Proceeds from sales of real estate placed in escrow	(104,696)	(201,857)
Proceeds from sales of real estate released from escrow	104,696	99,916
Cash released from scrow for land sale contracts	488	0
Deposit on real estate	0	(5,000)
Capital contributions to unconsolidated joint ventures	(10,215)	(2,444)
Capital distributions from unconsolidated joint ventures	0	24,527
Investments in securities, net	(438)	(884)
Net cash provided by (used in) investing activities	(109,357)	2,725
Cash flows from financing activities:
Repayments of mortgage notes payable	(6,265)	(7,024)
Proceeds from unsecured senior notes	997,080	0
Proceeds from real estate financing transaction	0	6,000
Payments on real estate financing transactions	(781)	(636)
Deferred financing costs	(8,047)	(20)
Net proceeds from equity transactions	(657)	(145)
Dividends and distributions	(328,567)	(883,684)
Contributions from noncontrolling interests in property partnerships	2,489	629
Distributions to noncontrolling interests in property partnerships	(12,915)	(17,974)
Net cash provided by (used in) financing activities	642,337	(902,854)
Net increase (decrease) in cash and cash equivalents	881,960	(698,683)
Cash and cash equivalents, beginning of period	723,718	1,763,079
Cash and cash equivalents, end of period	1,605,678	1,064,396
Supplemental disclosures:
Cash paid for interest	93,524	104,508
Interest capitalized	9,269	7,965
Non-cash investing and financing activities:
Additions to real estate included in accounts payable and accrued expenses	(24,857)	9,243
Dividends and distributions declared but not paid	113,079	112,796
Conversions of noncontrolling interests to stockholders’ equity	446	8,689
Issuance of restricted securities to employees	32,630	42,279
Boston Properties Limited Partnership
Cash flows from operating activities:
Net income	220,378	211,169
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	157,461	152,224
Non-cash compensation expense	10,069	11,011
Income from unconsolidated joint ventures	(1,791)	(14,834)
Distributions of net cash flow from operations of unconsolidated joint ventures	10,718	1,350
Gains from investments in securities	(259)	(393)
Non-cash portion of interest expense	(10,138)	(10,884)
Gains on sales of real estate	(69,792)	(95,084)
Change in assets and liabilities:
Cash held in escrows	1,940	1,044
Tenant and other receivables, net	25,018	(1,173)
Accrued rental income, net	(12,981)	(23,250)
Prepaid expenses and other assets	45,560	3,447
Accounts payable and accrued expenses	(5,209)	(5,535)
Accrued interest payable	31,192	23,098
Other liabilities	(33,319)	(23,136)
Tenant leasing costs	(19,867)	(27,608)
Total adjustments	128,602	(9,723)
Net cash provided by operating activities	348,980	201,446
Cash flows from investing activities:
Construction in progress	(122,940)	(60,013)
Building and other capital improvements	(25,329)	(19,391)
Tenant improvements	(55,739)	(26,950)
Proceeds from sales of real estate	104,816	194,821
Proceeds from sales of real estate placed in escrow	(104,696)	(201,857)
Proceeds from sales of real estate released from escrow	104,696	99,916
Cash released from scrow for land sale contracts	488	0
Deposit on real estate	0	(5,000)
Capital contributions to unconsolidated joint ventures	(10,215)	(2,444)
Capital distributions from unconsolidated joint ventures	0	24,527
Investments in securities, net	(438)	(884)
Net cash provided by (used in) investing activities	(109,357)	2,725
Cash flows from financing activities:
Repayments of mortgage notes payable	(6,265)	(7,024)
Proceeds from unsecured senior notes	997,080	0
Proceeds from real estate financing transaction	0	6,000
Payments on real estate financing transactions	(781)	(636)
Deferred financing costs	(8,047)	(20)
Net proceeds from equity transactions	(657)	(145)
Dividends and distributions	(328,567)	(883,684)
Contributions from noncontrolling interests in property partnerships	2,489	629
Distributions to noncontrolling interests in property partnerships	(12,915)	(17,974)
Net cash provided by (used in) financing activities	642,337	(902,854)
Net increase (decrease) in cash and cash equivalents	881,960	(698,683)
Cash and cash equivalents, beginning of period	723,718	1,763,079
Cash and cash equivalents, end of period	1,605,678	1,064,396
Supplemental disclosures:
Cash paid for interest	93,524	104,508
Interest capitalized	9,269	7,965
Non-cash investing and financing activities:
Additions to real estate included in accounts payable and accrued expenses	(24,857)	9,243
Dividends and distributions declared but not paid	113,079	112,796
Conversions of noncontrolling interests to stockholders’ equity	(446)	(8,689)
Issuance of restricted securities to employees	$ 32,630	$ 42,279

Organization

Organization	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	1. Organization Boston Properties, Inc., a Delaware corporation, is a fully integrated, self-administered and self-managed real estate investment trust (“REIT”). Boston Properties, Inc. is the sole general partner of Boston Properties Limited Partnership and at March 31, 2016 owned an approximate 89.4% ( 89.5% at December 31, 2015 ) general and limited partnership interest in Boston Properties Limited Partnership. Unless stated otherwise or the context requires, the “Company” refers to Boston Properties, Inc. and its subsidiaries, including Boston Properties Limited Partnership, its operating partnership, and its consolidated subsidiaries. Partnership interests in Boston Properties Limited Partnership include: • common units of partnership interest (also referred to as “OP Units”), • long term incentive units of partnership interest (also referred to as “LTIP Units”), and • preferred units of partnership interest (also referred to as “Preferred Units”). 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 Boston Properties Limited Partnership 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, Boston Properties Limited Partnership 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. The Company uses LTIP Units as a form of equity-based award for annual long-term incentive equity compensation. The Company has also issued LTIP Units to employees in the form of (1) 2012 outperformance plan awards (“2012 OPP Units”) and (2) 2013, 2014, 2015 and 2016 multi-year, long-term incentive program awards (also referred to as “2013 MYLTIP Units,” “2014 MYLTIP Units,” “2015 MYLTIP Units” and “2016 MYLTIP Units,” respectively, and collectively as “MYLTIP Units”), each of which, upon the satisfaction of certain performance and vesting conditions, is convertible into one OP Unit. The three-year measurement periods for the 2012 OPP Units and 2013 MYLTIP Units expired on February 6, 2015 and February 4, 2016, respectively, and Boston Properties, Inc.’s total stockholder return (“TSR”) was sufficient for employees to earn and therefore become eligible to vest in a portion of the awards. Unless and until they are earned, the rights, preferences and privileges of the 2014, 2015 and 2016 MYLTIP Units differ from other LTIP Units granted to employees (including, as of February 6, 2015, the 2012 OPP Units and, as of February 4, 2016, the 2013 MYLTIP Units). Therefore, unless specifically noted otherwise, all references to LTIP Units exclude the 2014, 2015 and 2016 MYLTIP Units. LTIP Units (including the 2012 OPP Units and the 2013 MYLTIP 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 Notes 8 , 9 and 11 ). At March 31, 2016 , there was one series of Preferred Units outstanding (i.e., Series B Preferred Units). The Series B Preferred Units were issued to Boston Properties, Inc. on March 27, 2013 in connection with 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 Boston Properties Limited Partnership in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock (See Note 9 ). Properties At March 31, 2016 , the Company owned or had interests in a portfolio of 167 commercial real estate properties (the “Properties”) aggregating approximately 46.3 million net rentable square feet of primarily Class A office properties, including eleven properties under construction/redevelopment totaling approximately 4.6 million net rentable square feet. At March 31, 2016 , the Properties consisted of: • 157 Office properties (including nine properties under construction/redevelopment); • one hotel; • five retail properties; and • four residential properties (including two properties under construction). The Company owns or controls undeveloped land parcels totaling approximately 457.1 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.

Basis Of Presentation And Summa

Basis Of Presentation And Summary Of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Basis Of Presentation And Summary Of Significant Accounting Policies	2. 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 Boston Properties Limited Partnership, nor does it have employees of its own. Boston Properties Limited Partnership, 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 (“VIEs”) 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 generally accepted accounting principles (“GAAP”) 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 GAAP 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 GAAP. 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, 2015 . Beginning on January 1, 2016, the properties that were historically part of the Company’s Office/Technical segment are reflected as Office properties (See Note 12 ). Fair Value of Financial Instruments The Company determines the fair value of its unsecured senior notes using market prices. The inputs used in determining the fair value of the Company’s unsecured 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 analysis by discounting the spread between the future contractual interest payments and hypothetical future interest payments on mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The inputs used in determining the fair value of the Company’s mortgage notes payable and mezzanine notes payable are categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs. Because the Company’s valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially if the Company’s estimates do not prove to be accurate. The following table presents the aggregate carrying value of the Company’s indebtedness and the Company’s corresponding estimate of fair value as of March 31, 2016 and December 31, 2015 (in thousands): March 31, 2016 December 31, 2015 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Mortgage notes payable, net $ 3,416,622 $ 3,477,310 $ 3,435,242 $ 3,503,746 Mezzanine notes payable 308,142 306,089 308,482 306,103 Unsecured senior notes, net 6,255,602 6,705,353 5,264,819 5,547,738 Total $ 9,980,366 $ 10,488,752 $ 9,008,543 $ 9,357,587 The Company uses interest rate swap agreements to manage its interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of March 31, 2016 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. Variable Interest Entities (VIEs) On January 1, 2016, the Company adopted Accounting Standards Update (“ASU”) ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis” (“ASU 2015-02”). ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 (1) modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities, (2) eliminates the presumption that a general partner should consolidate a limited partnership and (3) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. The Company reviewed all of their legal entities in accordance with ASU 2015-02 and concluded that certain of its legal entities, including Boston Properties Limited Partnership, which had been consolidated in accordance with the voting interest model are now variable interest entities under the VIE model, as discussed below. The adoption of the guidance did not alter any of the Company’s consolidation conclusions, but resulted in additional disclosures. Consolidated VIEs are those where the Company is considered to be the primary beneficiary of a VIE. The primary beneficiary is the entity that has a controlling financial interest in the VIE, which is defined by the entity having both of the following characteristics: 1) the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and 2) the obligation to absorb losses or the right to receive the returns from the VIE that could potentially be significant to the VIE. The Company has determined that is it the primary beneficiary for seven of the eight entities which are VIEs. Consolidated Variable Interest Entities As of March 31, 2016, Boston Properties, Inc. has identified seven consolidated VIEs, including Boston Properties Limited Partnership. These are the entities which own the following in-service properties: 767 Fifth Avenue (the General Motors Building), Time Square Tower, 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street, the entity that owns the Salesforce Tower which is currently under development and Boston Properties Limited Partnership. The Company consolidates these VIEs as it is the primary beneficiary. The third parties’ interests in these consolidated entities, with the exception of Boston Properties Limited Partnership, are reflected as noncontrolling interest in property partnerships in the accompanying Consolidated Financial Statements (See Note 8). In addition, Boston Properties, Inc.’s significant asset is its investment in Boston Properties Limited Partnership, and consequently, substantially all of Boston Properties, Inc.’s assets and liabilities represent the assets and liabilities of Boston Properties Limited Partnership. All of Boston Properties, Inc.’s debt is an obligation of Boston Properties Limited Partnership. Variable Interest Entities Not Consolidated The Company has determined that its BNY Tower Holdings LLC joint venture is a VIE. The Company does not consolidate this entity as the Company does not have the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and therefore, the Company is not considered to be the primary beneficiary. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“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”). In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date (“ASU 2015-14”), which delayed the effective date of ASU 2014-09 by one year making it effective for the first interim period within annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the original effective date. The Company is currently assessing the potential impact that the adoption of ASU 2014-09 will have on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”), which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs is not affected. ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years and shall be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Early adoption is permitted for financial statements that have not been previously issued. On January 1, 2016, the Company adopted ASU 2015-03 and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented. Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $3.2 million and $31.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of March 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments – Overall: Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2016-01”). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset, and eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost. ASU 2016-01 is effective for the Company for reporting periods beginning after December 15, 2017. Early application is permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-01 will have on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “ Leases ” (“ASU 2016-02”) , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). ASU 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. ASU 2016-02 is expected to impact the Company’s consolidated financial statements as the Company has certain operating land lease arrangements for which it is the lessee. ASU 2016-02 supersedes previous leasing standards . ASU 2016-02 is effective for the Company for reporting periods beginning after December 15, 2018, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-02 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships” (“ASU 2016-05”) which provides guidance clarifying that a novation of party to a derivative instrument, whereby one of the parties to a derivative instrument is replaced with another party, does not, in and of itself, require de-designation of that hedging relationship provided that all other hedge criteria continue to be met. ASU 2016-05 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-05 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”) . ASU 2016-09 is intended to improve the accounting for share-based payments and affects all organizations that issue share-based payment awards to their employees. Several aspects of the accounting for share-based payment awards are simplified with ASU 2016-09, including income tax consequences, classification of awards as equity or liabilities and classification on the statement of cash flows. ASU 2016-09 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-09 will have on its consolidated financial statements.

Real Estate Activity During the

Real Estate Activity During the Three Months Ended March 31, 2016	3 Months Ended
	Mar. 31, 2016
Real Estate [Abstract]
Real Estate Activity During the Three Months Ended March 31, 2016	3. Real Estate Activity During the Three Months Ended March 31, 2016 Dispositions On February 1, 2016, the Company completed the sale of its 415 Main Street property located in Cambridge, Massachusetts to the tenant for a gross sale price of approximately $105.4 million . Net cash proceeds totaled approximately $104.9 million , resulting in a gain on sale of real estate totaling approximately $60.8 million for Boston Properties, Inc. and approximately $63.0 million for Boston Properties Limited Partnership. As part of its lease signed on July 14, 2004, the tenant was granted a fixed-price option to purchase the building at the beginning of the 11th lease year, which option was exercised by the tenant on October 22, 2014. 415 Main Street is an office property with approximately 231,000 net rentable square feet. 415 Main Street contributed approximately $1.2 million and $2.6 million of net income to the Company for the period from January 1, 2016 through January 31, 2016 and for the three months ended March 31, 2015, respectively. Lease Terminations On February 3, 2016, the Company entered into a lease termination agreement with a tenant for an approximately 85,000 square foot lease at its 250 West 55th Street property located in New York City. The lease was scheduled to expire on February 28, 2035. In consideration for the termination of the lease, the tenant paid the Company approximately $45.0 million , which was recognized as termination income and is included in Base Rent in the accompanying Consolidated Statements of Operations for the three months ended March 31, 2016.

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	3 Months Ended
	Mar. 31, 2016
Investments In Unconsolidated Joint Ventures [Abstract]
Investments In Unconsolidated Joint Ventures	4. Investments in Unconsolidated Joint Ventures The investments in unconsolidated joint ventures consist of the following at March 31, 2016 and December 31, 2015 : Nominal % Ownership Carrying Value of Investment (1) Entity Properties March 31, 2016 December 31, 2015 (in thousands) Square 407 Limited Partnership Market Square North 50.0 % $ (9,506 ) $ (9,951 ) The Metropolitan Square Associates LLC Metropolitan Square 51.0 % 9,238 9,179 BP/CRF 901 New York Avenue LLC 901 New York Avenue 25.0 % (2) (11,617 ) (11,958 ) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.3 % (3) 43,057 43,524 Annapolis Junction NFM, LLC Annapolis Junction 50.0 % (4) (5) 21,134 29,009 540 Madison Venture LLC 540 Madison Avenue 60.0 % 67,715 68,983 500 North Capitol LLC 500 North Capitol Street, NW 30.0 % (3,470 ) (3,292 ) 501 K Street LLC 1001 6th Street 50.0 % (6) 42,540 42,584 Podium Developer LLC The Hub on Causeway 50.0 % 23,881 18,508 1265 Main Office JV LLC 1265 Main Street 50.0 % 16,143 11,916 BNY Tower Holdings LLC Dock72 at the Brooklyn Navy Yard 50.0 % (7) 12,196 11,521 $ 211,311 $ 210,023 _______________ (1) Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015 , respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets. (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 four in-service buildings and two undeveloped land parcels. (5) See Note 13. (6) Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization. (7) Entity is a VIE (See Note 2). Certain of the Company’s unconsolidated joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures at an agreed upon fair value. Under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners. The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows: March 31, 2016 December 31, 2015 (in thousands) ASSETS Real estate and development in process, net $ 1,041,533 $ 1,072,412 Other assets 225,200 252,285 Total assets $ 1,266,733 $ 1,324,697 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 829,089 $ 830,125 Other liabilities 38,920 44,549 Members’/Partners’ equity 398,724 450,023 Total liabilities and members’/partners’ equity $ 1,266,733 $ 1,324,697 Company’s share of equity $ 238,166 $ 237,070 Basis differentials (1) (26,855 ) (27,047 ) Carrying value of the Company’s investments in unconsolidated joint ventures (2) $ 211,311 $ 210,023 _______________ (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. (2) Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015 , respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets. The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows: For the three months ended March 31, 2016 2015 (in thousands) Total revenue (1) $ 37,669 $ 39,532 Expenses Operating 16,667 16,275 Depreciation and amortization 9,064 9,071 Total expenses 25,731 25,346 Operating income 11,938 14,186 Other expense Interest expense 8,389 7,980 Net income $ 3,549 $ 6,206 Company’s share of net income $ 1,599 $ 14,642 (2) Basis differential 192 192 Income from unconsolidated joint ventures $ 1,791 $ 14,834 _______________ (1) Includes straight-line rent adjustments of approximately $2.2 million and $1.6 million for the three months ended March 31, 2016 and 2015 , respectively. (2) During the three months ended March 31, 2015, the Company received a distribution of approximately $24.5 million , which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10 -year mortgage loan totaling $225.0 million . The Company’s allocation of income and distributions for the three months ended March 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement.

Unsecured Senior Notes Unsecure

Unsecured Senior Notes Unsecured Senior Notes	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Unsecured Senior Notes	5. Unsecured Senior Notes The following summarizes the unsecured senior notes outstanding as of March 31, 2016 (dollars in thousands): Coupon/ Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 10 Year Unsecured Senior Notes 5.875 % 5.967 % $ 700,000 October 15, 2019 10 Year Unsecured Senior Notes 5.625 % 5.708 % 700,000 November 15, 2020 10 Year Unsecured Senior Notes 4.125 % 4.289 % 850,000 May 15, 2021 7 Year Unsecured Senior Notes 3.700 % 3.853 % 850,000 November 15, 2018 11 Year Unsecured Senior Notes 3.850 % 3.954 % 1,000,000 February 1, 2023 10.5 Year Unsecured Senior Notes 3.125 % 3.279 % 500,000 September 1, 2023 10.5 Year Unsecured Senior Notes 3.800 % 3.916 % 700,000 February 1, 2024 10 Year Unsecured Senior Notes 3.650 % 3.766 % 1,000,000 February 1, 2026 Total principal 6,300,000 Net unamortized discount (13,148 ) Deferred financing costs, net (31,250 ) Total $ 6,255,602 _______________ (1) Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs. (2) No principal amounts are due prior to maturity. The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60% , (2) a secured debt leverage ratio not to exceed 50% , (3) an interest coverage ratio of greater than 1.50 , and (4) an unencumbered asset value of not less than 150% of unsecured debt. At March 31, 2016 , Boston Properties Limited Partnership was in compliance with each of these financial restrictions and requirements. On January 20, 2016, Boston Properties Limited Partnership completed a public offering of $1.0 billion in aggregate principal amount of its 3.650% senior unsecured notes due 2026. The notes were priced at 99.708% of the principal amount to yield an effective rate (including financing fees) of 3.766% to maturity. The notes will mature on February 1, 2026, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $988.9 million after deducting underwriting discounts and transaction expenses.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities (Notes)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities [Text Block]	6. Derivative Instruments and Hedging Activities As of March 31, 2016 , Boston Properties Limited Partnership has entered into seventeen forward-starting interest rate swap contracts that fix the 10 -year swap rate at a weighted-average rate of approximately 2.423% per annum on notional amounts aggregating $550.0 million . These interest rate swap contracts were entered into in advance of a financing with a target commencement date in September 2016 and maturity in September 2026. In addition, as of March 31, 2016 , 767 Fifth Partners LLC, which is the consolidated entity (in which the Company has a 60% interest and owns 767 Fifth Avenue (the General Motors Building) in New York City), has entered into sixteen forward-starting interest rate swap contracts (including two contracts entered into during the three months ended March 31, 2016 with notional amounts aggregating $50.0 million ), which fix the 10 -year swap rate at a weighted-average rate of approximately 2.619% per annum on notional amounts aggregating $450.0 million . These interest rate swap contracts were entered into in advance of a financing with a target commencement date in June 2017 and maturity in June 2027. Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at March 31, 2016 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 550,000 September 1, 2016 September 1, 2026 2.129 % - 2.571 % Other Liabilities $ (36,561 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 450,000 June 7, 2017 June 7, 2027 2.336 % - 2.950 % Other Liabilities $ (32,387 ) $ 1,000,000 $ (68,948 ) Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2015 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 400,000 September 1, 2016 September 1, 2026 2.348 % - 2.571 % Other Liabilities $ (5,419 ) Interest Rate Swaps 150,000 September 1, 2016 September 1, 2026 2.129 % - 2.325 % Prepaid Expenses and Other Assets 1,188 $ 550,000 $ (4,231 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 250,000 June 7, 2017 June 7, 2027 2.677 % - 2.950 % Other Liabilities $ (7,247 ) Interest Rate Swaps 150,000 June 7, 2017 June 7, 2027 2.336 % - 2.430 % Prepaid Expenses and Other Assets 1,176 $ 400,000 $ (6,071 ) $ 950,000 $ (10,302 ) Boston Properties Limited Partnership entered into the interest rate swap contracts designated and qualifying as cash flow hedges to reduce its exposure to the variability in future cash flows attributable to changes in the 10 -year swap rate in contemplation of obtaining 10 -year fixed-rate financing in September 2016. The Company’s 767 Fifth Partners LLC consolidated entity entered into the interest rate swap contracts designated and qualifying as cash flow hedges to reduce its exposure to the variability in future cash flows attributable to changes in the 10 -year swap rate in contemplation of obtaining 10 -year fixed-rate financing in June 2017. Boston Properties Limited Partnership has formally documented all of its relationships between hedging instruments and hedged items, as well as its risk-management objective and strategy for undertaking various hedge transactions. Boston Properties Limited Partnership also assesses and documents, both at the hedging instrument’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows associated with the hedged items. All components of the forward-starting interest rate swap contracts were included in the assessment of hedge effectiveness. Boston Properties Limited Partnership has agreements with each of its derivative counterparties that contain a provision where it could be declared in default on its derivative obligations if repayment of its indebtedness is accelerated by the lender due to its default on the indebtedness. As of March 31, 2016 , the fair value of derivatives in a liability position, excluding any adjustment for nonperformance risk and excluding accrued interest, related to these agreements was approximately $69.3 million . As of March 31, 2016 , Boston Properties Limited Partnership has not posted any collateral related to these agreements. If Boston Properties Limited Partnership had breached any of these provisions at March 31, 2016 , it could have been required to settle its obligations under the agreements at their termination value of approximately $69.3 million . The Company accounts for the effective portion of changes in the fair value of a derivative in accumulated other comprehensive loss and subsequently reclassifies the effective portion to earnings over the term that the hedged transaction affects earnings. The Company accounts for the ineffective portion of changes in the fair value of a derivative directly in earnings. During the three months ended March 31, 2016 , the Company has recorded the changes in fair value of the swap contracts related to the effective portion of the interest rate contracts aggregating approximately $68.9 million in Other Liabilities and Accumulated Other Comprehensive Loss within the Company’s Consolidated Balance Sheets. During the three months ended March 31, 2016 , the Company did not record any hedge ineffectiveness. The Company expects that within the next twelve months it will reclassify into earnings as an increase to interest expense approximately $2.1 million of the amounts recorded within Accumulated Other Comprehensive Loss relating to the forward-starting interest rate swap contracts in effect and as of March 31, 2016 . The following table presents the location in the financial statements of the losses recognized related to the Company’s cash flow hedges for the three months ended March 31, 2016 and 2015 : Three months ended 2016 2015 (in thousands) Amount of loss related to the effective portion recognized in other comprehensive loss $ (58,646 ) $ (3,533 ) Amount of loss related to the effective portion subsequently reclassified to earnings (1) $ (627 ) $ (627 ) Amount of gain (loss) related to the ineffective portion and amount excluded from effectiveness testing $ — $ — ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015. Boston Properties, Inc. The following table reflects the changes in accumulated other comprehensive loss for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ (14,114 ) Effective portion of interest rate contracts (58,646 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 15,427 Balance at March 31, 2016 $ (56,706 ) Balance at December 31, 2014 $ (9,304 ) Effective portion of interest rate contracts (3,533 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 303 Balance at March 31, 2015 $ (11,907 ) ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015. Boston Properties Limited Partnership The following table reflects the changes in accumulated other comprehensive loss for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ (18,337 ) Effective portion of interest rate contracts (58,646 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 10,526 Balance at March 31, 2016 $ (65,830 ) Balance at December 31, 2014 $ (12,973 ) Effective portion of interest rate contracts (3,533 ) Amortization of interest rate contracts (1) 627 Balance at March 31, 2015 $ (15,879 ) ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015.

Commitments And Contingencies

Commitments And Contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	7. 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 related to lender and development requirements that total approximately $22.5 million . 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. 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 entity, 767 Venture, LLC, the Company guaranteed the consolidated joint venture’s obligation to fund various escrows, including tenant improvements, taxes and insurance in lieu of cash deposits. As of March 31, 2016 , the maximum funding obligation under the guarantee was approximately $16.2 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 767 Fifth Partners LLC entering into interest rate swap contracts (See Note 6 ), the Company guaranteed 767 Fifth Partners LLC’s obligations under the hedging agreements in favor of each hedge counterparty. 767 Fifth Partners LLC is the entity that owns 767 Fifth Avenue (the General Motors Building). It is a subsidiary of 767 Venture, LLC, a consolidated entity in which the Company has a 60% interest. 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 Fountain Square property located in Reston, Virginia, the Company has agreed to guarantee approximately $0.7 million related to its obligation to provide funds for certain tenant re-leasing costs. The mortgage financing is scheduled to mature on October 11, 2016 (See Note 13 ). 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 approximately $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 approximately $45.2 million . During 2014, the Company received a distribution totaling approximately $7.7 million . During 2015, the Company received distributions aggregating approximately $8.1 million , including approximately $4.5 million received on March 11, 2015, which is included in Base Rent in the accompanying Consolidated Statements of Operations for the three months ended March 31, 2015, leaving a remaining claim of approximately $29.4 million . The Company will continue to evaluate whether to attempt to sell the remaining claim or wait until the trustee distributes proceeds from the Lehman Brothers estate. Given the inherent uncertainties in bankruptcy proceedings, there can be no assurance as to the timing or amount of additional proceeds, if any, that the Company may ultimately realize on the remaining 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 March 31, 2016 . 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 and further extended to December 31, 2020 by the Terrorism Risk Insurance Program Reauthorization Act of 2015 (“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. 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 is backstopped by the Federal Government if the aggregate industry insured losses resulting from a certified act of terrorism exceed a “program trigger.” In 2016, the program trigger is $120 million and the coinsurance is 16% , however, both will increase in subsequent years pursuant to 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. 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 3% of the value of the affected property. Specifically, the Company currently carries earthquake insurance which covers its San Francisco region (excluding Salesforce Tower) with a $170 million per occurrence limit, and a $170 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 Salesforce Tower in San Francisco includes a $60 million per occurrence and annual aggregate limit of earthquake coverage. The amount of the Company’s earthquake insurance coverage may not be sufficient to cover losses from earthquakes. In addition, the amount of earthquake coverage could impact the Company’s ability to finance properties subject to earthquake risk. The Company may discontinue earthquake insurance or change the structure of its earthquake insurance program on some or all of its properties in the future if the premiums exceed the Company’s estimation of the value of the coverage. IXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s earthquake insurance coverage for its Greater San Francisco properties and the Company’s NBCR Coverage. Insofar as the Company owns IXP, it is responsible for its liquidity and capital resources, and the accounts of IXP 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 would also be responsible for any recoupment charges by the Federal Government in the event losses are paid out and its insurance policy is maintained after the payout by the Federal Government. If the Company experiences a loss and IXP is required to pay under its insurance policy, the Company would ultimately record the loss to the extent of the required payment. Therefore, insurance coverage provided by IXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In addition, Boston Properties Limited Partnership has issued a guarantee to cover liabilities of IXP in the amount of $20.0 million . The mortgages on the Company’s properties typically contain requirements concerning the financial ratings of the insurers who provide policies covering the property. The Company provides the lenders on a regular basis with the identity of the insurance companies in the Company’s insurance programs. The ratings of some of the Company’s insurers are below the rating requirements in some of the Company’s loan agreements and the lenders for these loans could attempt to claim that an event of default has occurred under the loan. The Company believes it could obtain insurance with insurers which satisfy the rating requirements. Additionally, in the future, the Company’s ability to obtain debt financing secured by individual properties, or the terms of such financing, may be adversely affected if lenders generally insist on ratings for insurers or amounts of insurance which are difficult to obtain or which result in a commercially unreasonable premium. There can be no assurance that a deficiency in the financial ratings of one or more of the Company’s insurers will not have a material adverse effect on the Company. The Company continues to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism and California earthquake risk in particular, but the Company cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, for which the Company cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes or other catastrophic events, if the Company experiences a loss that is uninsured or that exceeds policy limits, the Company could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that the Company could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect the Company’s business and financial condition and results of operations.

Noncontrolling Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interests	8. Noncontrolling Interests Noncontrolling interests relate to the interests in Boston Properties Limited Partnership not owned by Boston Properties, Inc. and interests in consolidated property partnerships not wholly-owned by the Company. As of March 31, 2016 , the noncontrolling interests in Boston Properties Limited Partnership consisted of 16,092,449 OP Units, 2,065,185 LTIP Units (including 215,709 2012 OPP Units and 103,882 2013 MYLTIP Units), 475,558 2014 MYLTIP Units, 367,936 2015 MYLTIP Units and 474,456 2016 MYLTIP Units held by parties other than Boston Properties, Inc. Noncontrolling Interest—Redeemable Preferred Units On June 25, 2015, Boston Properties Limited Partnership redeemed the remaining 12,667 Series Four Preferred Units for cash totaling approximately $0.6 million , plus accrued and unpaid distributions. The Series Four Preferred Units bore a preferred distribution equal to 2.00% per annum on a liquidation preference of $50.00 per unit and were not convertible into OP Units. The holders of Series Four Preferred Units had 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 Boston Properties Limited Partnership to redeem all of their units for cash at the redemption price of $50.00 per unit. Boston Properties Limited Partnership also had 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 was released. Due to the holders’ redemption option existing outside the control of the Company, the Series Four Preferred Units were presented outside of permanent equity in the Company’s Consolidated Balance Sheets. The following table reflects the activity of the noncontrolling interests—redeemable preferred units for the three months ended March 31, 2015 (in thousands): Balance at December 31, 2014 $ 633 Net income 3 Distributions (3 ) Balance at March 31, 2015 $ 633 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 50% interest in the joint venture. The Company contributed cash totaling approximately $87.0 million for its 50% interest, which cash was distributed to the joint venture partner. Pursuant to the joint venture agreement (i) the Company had rights to acquire the partner’s 50% interest and (ii) the partner had 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 were to expire on January 31, 2016 . The Company was consolidating this joint venture due to the Company’s right to acquire the partner’s 50% interest. The Company 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 was accreting 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 was recording the accretion after the allocation of net income and distributions of cash flow to the noncontrolling interest account balance. On August 6, 2015, the parties amended the joint venture agreement to require the Company to acquire its partner’s 50% interest on September 15, 2015 for approximately $100.9 million in cash. On September 15, 2015, the Company acquired its partner’s 50% interest in the consolidated entity that owns Fountain Square located in Reston Town Center in Reston, Virginia for cash of approximately $100.9 million plus working capital and closing prorations and the partner's share of assumed mortgage indebtedness totaling approximately $105.6 million . The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company’s Fountain Square consolidated entity for the three months ended March 31, 2015 (in thousands): Balance at December 31, 2014 $ 104,692 Net income 75 Distributions (1,400 ) Adjustment to reflect redeemable interest at redemption value 2,153 Balance at March 31, 2015 $ 105,520 Noncontrolling Interest—Common Units During the three months ended March 31, 2016 , 13,259 OP Units were presented by the holders for redemption (including 7,277 OP Units issued upon conversion of LTIP Units and 2012 OPP Units) and were redeemed by Boston Properties, Inc. in exchange for an equal number of shares of Common Stock. At March 31, 2016 , Boston Properties Limited Partnership had outstanding 475,558 2014 MYLTIP Units, 367,936 2015 MYLTIP Units and 474,456 2016 MYLTIP Units. Prior to the applicable measurement date (February 3, 2017 for 2014 MYLTIP Units, February 4, 2018 for 2015 MYLTIP Units and February 9, 2019 for 2016 MYLTIP Units), holders of 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 MYLTIP Units, both vested and unvested, that 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 February 6, 2015, the measurement period for the Company’s 2012 OPP Unit awards ended and Boston Properties, Inc.’s TSR performance was sufficient for employees to earn and therefore become eligible to vest in a portion of the 2012 OPP Unit awards. The final outperformance pool was determined to be approximately $32.1 million , or approximately 80% of the total maximum outperformance pool of $40.0 million . As a result, 174,549 2012 OPP Units were automatically forfeited. On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target or an aggregate of approximately $13.5 million . As a result, 205,762 2013 MYLTIP Units were automatically forfeited. The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units and, after the measurement date, the 2013 MYLTIP Units) and its distributions on the 2013 MYLTIP Units (prior to the February 4, 2016 measurement date), 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units (after the February 10, 2016 issuance date) for the periods presented: Record Date Payment Date Distributions on the OP Units and LTIP Units Distributions on MYLTIP Units March 31, 2016 April 29, 2016 $0.65 $0.065 December 31, 2015 January 28, 2016 $1.90 (1) $0.065 _______________ (1) Includes a special distribution of $1.25 per unit. A holder of an OP Unit may present such OP Unit to Boston Properties Limited Partnership 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, Boston Properties Limited Partnership must redeem such OP Unit for cash equal to the then value of a share of common stock of Boston Properties, Inc. Boston Properties, Inc. may, in its sole discretion, elect to assume and satisfy the redemption obligation by paying either cash or issuing one share of Common Stock. The value of the OP Units not owned by Boston Properties, Inc. and LTIP Units (including the 2012 OPP Units and 2013 MYLTIP Units) assuming that all conditions had been met for the conversion thereof had all of such units been redeemed at March 31, 2016 was approximately $2.3 billion based on the closing price of Boston Properties, Inc.’s common stock of $127.08 per share on March 31, 2016 . Boston Properties Limited Partnership The following table reflects the activity of noncontrolling interests—redeemable common units of Boston Properties Limited Partnership for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ 2,286,689 Contributions 30,808 Net income 21,393 Distributions (11,865 ) Conversion of redeemable partnership units (446 ) Unearned compensation (22,424 ) Accumulated other comprehensive loss (4,901 ) Adjustment to reflect redeemable partnership units at redemption value 8,218 Balance at March 31, 2016 $ 2,307,472 Balance at December 31, 2014 $ 2,310,046 Contributions 38,371 Net income 20,188 Distributions (11,705 ) Conversion of redeemable partnership units (8,689 ) Unearned compensation (18,597 ) Accumulated other comprehensive loss (303 ) Adjustment to reflect redeemable partnership units at redemption value 211,747 Balance at March 31, 2015 $ 2,541,058 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 $1.6 billion at March 31, 2016 and December 31, 2015 , are included in Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets. On September 18, 2015, a consolidated entity in which the Company has a 50% interest completed the sale of its 505 9th Street, N.W. property located in Washington, DC for approximately $318.0 million , including the assumption by the buyer of approximately $117.0 million of mortgage indebtedness. 505 9th Street, N.W. is an approximately 322,000 net rentable square foot Class A office building. Net cash proceeds totaled approximately $194.6 million , of which the partners’ share was approximately $97.3 million . The Company recognized a gain on sale of real estate totaling approximately $199.5 million and $199.7 million for Boston Properties, Inc. and Boston Properties Limited Partnership, respectively, of which approximately $101.1 million was allocated to the outside partners. The following table reflects the activity of the noncontrolling interests in property partnerships for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ 1,574,400 Capital contributions 2,489 Net income 10,464 Accumulated other comprehensive loss (10,526 ) Distributions (12,915 ) Balance at March 31, 2016 $ 1,563,912 Balance at December 31, 2014 $ 1,602,467 Capital contributions 629 Net income 12,980 Distributions (16,574 ) Balance at March 31, 2015 $ 1,599,502

Stockholders' Equity _ Partners

Stockholders' Equity / Partners'' Capital	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Stockholders' Equity / Partners' Capital	9. Stockholders’ Equity / Partners’ Capital As of March 31, 2016 , Boston Properties, Inc. had 153,604,966 shares of Common Stock outstanding. As of March 31, 2016 , Boston Properties, Inc. owned 1,717,626 general partnership units and 151,887,340 limited partnership units of Boston Properties Limited Partnership. On June 3, 2014, Boston Properties, Inc. established an “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. The Company intends to use the net proceeds from any offering for general business purposes, which may include investment opportunities and debt reduction. No shares of common stock have been issued under this ATM stock offering program since its inception. During the three months ended March 31, 2016 , Boston Properties, Inc. issued 13,259 shares of Common Stock in connection with the redemption of an equal number of redeemable OP Units from third parties. The following table presents Boston Properties, Inc.’s dividends per share and Boston Properties Limited Partnership’s distributions per unit for the periods presented: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 31, 2016 April 29, 2016 $0.65 $0.65 December 31, 2015 January 28, 2016 $1.90 (1) $1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/common unit. Preferred Stock As of March 31, 2016 , 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. pays 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. or its affiliates. The following table presents Boston Properties Inc.’s dividends per share on its outstanding Series B Preferred Stock: Record Date Payment Date Dividend (Per Share) May 5, 2016 May 16, 2016 $32.8125 February 5, 2016 February 16, 2016 $32.8125

Earnings Per Share _ Common Uni

Earnings Per Share / Common Unit	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share / Common Unit	10. Earnings Per Share / Common Unit Boston Properties, Inc. The following table provides a reconciliation of both the net income attributable to Boston Properties, Inc. common shareholders and the number of common shares used in the computation of basic earnings per share (“EPS”), which is calculated by dividing net income attributable to Boston Properties, Inc. common shareholders by the weighted-average number of common shares outstanding during the period. 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 the Company, LTIP Units, 2012 OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic EPS of the Company using the two -class method. Participating securities are included in the computation of diluted EPS of the Company using the if-converted method if the impact is dilutive. Because the 2012 OPP Units and 2013 MYLTIP Units required and the 2014-2016 MYLTIP Units require the Company 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 EPS calculation. Other potentially dilutive common shares, including stock options, restricted stock and other securities of Boston Properties Limited Partnership that are exchangeable for the Boston Properties, Inc.’s Common Stock, and the related impact on earnings, are considered when calculating diluted EPS. For the three months ended March 31, 2016 Income (Numerator) Shares (Denominator) Per Share Amount (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 153,626 $ 1.18 Allocation of undistributed earnings to participating securities (247 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 181,500 153,626 $ 1.18 Effect of Dilutive Securities: Stock Based Compensation — 291 — Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 181,500 153,917 $ 1.18 For the three months ended March 31, 2015 Income (Numerator) Shares (Denominator) Per Share Amount (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 171,182 153,230 $ 1.12 Allocation of undistributed earnings to participating securities (188 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 170,994 153,230 $ 1.12 Effect of Dilutive Securities: Stock Based Compensation — 643 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 170,994 153,873 $ 1.11 Boston Properties Limited Partnership The following table provides a reconciliation of both the net income attributable to Boston Properties Limited Partnership common unitholders 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 common unitholders by the weighted-average number of common units outstanding during the period. 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 Boston Properties Limited Partnership’s LTIP Units, 2012 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 2012 OPP Units and 2013 MYLTIP Units required and the 2014-2016 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, Boston Properties Limited Partnership 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 17,683,000 and 17,854,000 redeemable common units for the three months ended March 31, 2016 and 2015 , respectively. For the three months ended March 31, 2016 Income (Numerator) Units (Denominator) Per Unit Amount (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 171,309 $ 1.21 Allocation of undistributed earnings to participating securities (275 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,021 171,309 $ 1.21 Effect of Dilutive Securities: Stock Based Compensation — 291 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,021 171,600 $ 1.21 For the three months ended March 31, 2015 Income (Numerator) Units (Denominator) Per Unit Amount (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,369 171,084 $ 1.13 Allocation of undistributed earnings to participating securities (210 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,159 171,084 $ 1.13 Effect of Dilutive Securities: Stock Based Compensation — 643 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,159 171,727 $ 1.12

Stock Option and Incentive Plan

Stock Option and Incentive Plan	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plan	11. Stock Option and Incentive Plan On January 25, 2016, Boston Properties Inc.’s Compensation Committee approved the 2016 MYLTIP awards under Boston Properties Inc.’s 2012 Stock Option and Incentive Plan (the “2012 Plan”) to certain officers and employees of Boston Properties, Inc. The 2016 MYLTIP awards utilize TSR over a three -year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards will be based on Boston Properties, Inc.’s TSR relative to (i) the Cohen & Steers Realty Majors Portfolio Index ( 50% weight) and (ii) the NAREIT Office Index adjusted to include Vornado Realty Trust and exclude Boston Properties, Inc. ( 50% weight). Earned awards will range from zero to a maximum of approximately $49.3 million depending on Boston Properties, Inc.’s TSR relative to the two indices, with three tiers (threshold: approximately $9.9 million ; target: approximately $19.7 million ; high: approximately $49.3 million ) and linear interpolation between tiers. Earned awards measured on the basis of relative TSR performance are subject to an absolute TSR component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.’s annualized TSR is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.’s annualized TSR is more than 12% even though on a relative basis alone Boston Properties, Inc.’s TSR would not result in any earned awards. Earned awards (if any) will vest 50% on February 9, 2019 and 50% on February 9, 2020, 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, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 9, 2019, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2016 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 OP Units and no special distributions. Under the FASB’s ASC 718 “Compensation-Stock Compensation,” the 2016 MYLTIP awards have an aggregate value of approximately $17.3 million , which amount will generally be amortized into earnings over the four -year plan period under the graded vesting method. On February 6, 2015, the measurement period for the Company’s 2012 OPP Unit awards ended and Boston Properties, Inc.’s TSR performance was sufficient for employees to earn and therefore become eligible to vest in a portion of the 2012 OPP Unit awards. The final outperformance pool was determined to be approximately $32.1 million , or approximately 80% of the total maximum outperformance pool of $40.0 million . As a result, 174,549 2012 OPP Units were automatically forfeited. On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target or an aggregate of approximately $13.5 million . As a result, 205,762 2013 MYLTIP Units were automatically forfeited. During the three months ended March 31, 2016 , Boston Properties, Inc. issued 18,521 shares of restricted common stock and Boston Properties Limited Partnership issued 139,435 LTIP Units and 475,004 2016 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 2016 MYLTIP Unit. When issued, LTIP Units are not economically equivalent in value to a share of Common Stock, but over time can increase in value to one-for-one parity with Common Stock if there is sufficient appreciation in the value of the Company’s assets. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets. Grants of restricted stock and LTIP Units to employees vest in four equal annual installments. Restricted stock is measured at fair value on the date of grant based on the number of shares granted, as adjusted for forfeitures, and the closing price of Boston Properties, Inc.’s Common Stock on the date of grant as quoted on the New York Stock Exchange. Such value is recognized as an expense ratably over the corresponding employee service period. The shares of restricted stock granted during the three months ended March 31, 2016 were valued at approximately $2.1 million ( $111.14 per share). The LTIP Units granted were valued at approximately $14.4 million ( $103.26 per unit weighted-average fair value) using a Monte Carlo simulation method model. The per unit fair values of the LTIP Units granted were estimated on the dates of grant and for a substantial majority of such units were valued using the following assumptions: an expected life of 5.7 years , a risk-free interest rate of 1.61% and an expected price volatility of 33% . As the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units are subject to both a service condition and a market condition, the Company recognizes the compensation expense related to the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 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 Dividends in Excess of Earnings in Boston Properties, Inc.’s Consolidated Balance Sheets and Partners’ Capital in Boston Properties Limited Partnership’s Consolidated Balance Sheets. Aggregate stock-based compensation expense associated with restricted stock, non-qualified stock options, LTIP Units, 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units was approximately $9.4 million and $10.1 million for the three months ended March 31, 2016 and 2015 , respectively. At March 31, 2016 , there was $30.4 million of unrecognized compensation expense related to unvested restricted stock, LTIP Units, 2012 OPP Units and 2013 MYLTIP Units and $29.6 million of unrecognized compensation expense related to unvested 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 2.9 years .

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Segment Information	12. 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. The Company’s segments by geographic area are Boston, New York, San Francisco and Washington, DC. Segments by property type include: Office, 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, interest expense, depreciation and amortization expense, gains (losses) from investments in securities, income from unconsolidated joint ventures, gains on sales of real estate, noncontrolling interests and preferred dividends/distributions 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 GAAP, 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, Inc. common shareholders and net income attributable to Boston Properties Limited Partnership common unitholders. The Company has modified the presentation of its Office/Technical properties to be included within Office properties to align with its method of internal reporting, which shifted after the disposition of 415 Main Street in Cambridge, Massachusetts. As such, the amounts previously included in Office/Technical are now included in Office for all periods presented. Information by geographic area and property type (dollars in thousands): For the three months ended March 31, 2016 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 177,827 $ 291,858 $ 76,317 $ 100,488 $ 646,490 Residential 1,171 — — 2,878 4,049 Hotel 8,757 — — — 8,757 Total 187,755 291,858 76,317 103,366 659,296 % of Grand Totals 28.48 % 44.27 % 11.57 % 15.68 % 100.00 % Rental Expenses: Office 70,687 88,798 23,905 34,182 217,572 Residential 520 — — 1,080 1,600 Hotel 7,634 — — — 7,634 Total 78,841 88,798 23,905 35,262 226,806 % of Grand Totals 34.76 % 39.15 % 10.54 % 15.55 % 100.00 % Net operating income $ 108,914 $ 203,060 $ 52,412 $ 68,104 $ 432,490 % of Grand Totals 25.18 % 46.95 % 12.12 % 15.75 % 100.00 % For the three months ended March 31, 2015 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 176,027 $ 253,098 $ 71,911 $ 96,173 $ 597,209 Residential 1,178 — — 5,676 6,854 Hotel 9,085 — — — 9,085 Total 186,290 253,098 71,911 101,849 613,148 % of Grand Totals 30.38 % 41.28 % 11.73 % 16.61 % 100.00 % Rental Expenses: Office 76,451 85,061 22,821 33,471 217,804 Residential 509 — — 3,037 3,546 Hotel 7,576 — — — 7,576 Total 84,536 85,061 22,821 36,508 228,926 % of Grand Totals 36.92 % 37.16 % 9.97 % 15.95 % 100.00 % Net operating income $ 101,754 $ 168,037 $ 49,090 $ 65,341 $ 384,222 % of Grand Totals 26.48 % 43.73 % 12.78 % 17.01 % 100.00 % Boston Properties, Inc. The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties, Inc. common shareholders: Three months ended 2016 2015 (in thousands) Net Operating Income $ 432,490 $ 384,222 Add: Development and management services income 6,689 5,328 Income from unconsolidated joint ventures 1,791 14,834 Interest and other income 1,505 1,407 Gains from investments in securities 259 393 Gains on sales of real estate 67,623 95,084 Less: General and administrative expense 29,353 28,791 Transaction costs 25 327 Depreciation and amortization expense 159,448 154,223 Interest expense 105,309 108,757 Noncontrolling interests in property partnerships 10,464 15,208 Noncontrolling interest—redeemable preferred units of the Operating Partnership — 3 Noncontrolling interest—common units of the Operating Partnership 21,393 20,188 Preferred dividends 2,618 2,589 Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 $ 171,182 Boston Properties Limited Partnership The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership common unitholders: Three months ended 2016 2015 (in thousands) Net Operating Income $ 432,490 $ 384,222 Add: Development and management services income 6,689 5,328 Income from unconsolidated joint ventures 1,791 14,834 Interest and other income 1,505 1,407 Gains from investments in securities 259 393 Gains on sales of real estate 69,792 95,084 Less: General and administrative expense 29,353 28,791 Transaction costs 25 327 Depreciation and amortization expense 157,461 152,224 Interest expense 105,309 108,757 Noncontrolling interests in property partnerships 10,464 15,208 Noncontrolling interest—redeemable preferred units — 3 Preferred distributions 2,618 2,589 Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 $ 193,369

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events On April 4, 2016, a joint venture in which the Company has a 50% interest extended the loan collateralized by its Annapolis Junction Building Seven property. At the time of the extension, the outstanding balance of the construction loan totaled approximately $21.5 million and was scheduled to mature on April 4, 2016. The extended loan has a total commitment amount of $22.0 million , bears interest at a variable rate equal to LIBOR plus 1.65% per annum and matures on April 4, 2017, with one , one -year extension option, subject to certain conditions. Annapolis Junction Building Seven is a Class A office property with approximately 127,000 net rentable square feet located in Annapolis, Maryland. On April 11, 2016, the Company used available cash to repay the mortgage loan collateralized by its Fountain Square property located in Reston, Virginia totaling approximately $211.3 million . The mortgage loan bore interest at a fixed rate of 5.71% per annum and was scheduled to mature on October 11, 2016. There was no prepayment penalty. On April 11, 2016, a joint venture in which the Company has a 50% interest received a Notice of Event of Default from the lender for the loan collateralized by its Annapolis Junction Building One property. The Event of Default relates to the loan to value ratio not being in compliance with the loan agreement. The joint venture is currently in discussions with the lender regarding the Event of Default, although there can be no assurance as to the outcome of those discussions. The estimated fair value of the Company’s investment in the unconsolidated joint venture exceeds its carrying value. The loan has an outstanding balance of approximately $40.0 million , is non-recourse to the Company, bears interest at a variable rate equal to LIBOR plus 1.75% per annum and has a stated maturity date of March 31, 2018, with one , three -year extension option, subject to certain conditions. Annapolis Junction Building One is a Class A office property with approximately 118,000 net rentable square feet located in Annapolis, Maryland. On April 22, 2016, the Company acquired 3625-35 Peterson Way located in Santa Clara, California for a purchase price of approximately $78.0 million in cash. 3625-35 Peterson Way is an approximately 218,000 net rentable square foot office property. The property is 100% leased to a single tenant through March 2021. Upon the lease expiration, the Company intends to develop the site into a Class A office campus containing an aggregate of approximately 632,000 net rentable square feet.

Basis Of Presentation And Sum22

Basis Of Presentation And Summary Of Significant Accounting Policies Recent Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2016
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncement [Policy Text Block]	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“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”). In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date (“ASU 2015-14”), which delayed the effective date of ASU 2014-09 by one year making it effective for the first interim period within annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the original effective date. The Company is currently assessing the potential impact that the adoption of ASU 2014-09 will have on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”), which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs is not affected. ASU 2015-03 is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years and shall be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Early adoption is permitted for financial statements that have not been previously issued. On January 1, 2016, the Company adopted ASU 2015-03 and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented. Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $3.2 million and $31.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of March 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments – Overall: Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2016-01”). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset, and eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost. ASU 2016-01 is effective for the Company for reporting periods beginning after December 15, 2017. Early application is permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-01 will have on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “ Leases ” (“ASU 2016-02”) , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e. lessees and lessors). ASU 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. ASU 2016-02 is expected to impact the Company’s consolidated financial statements as the Company has certain operating land lease arrangements for which it is the lessee. ASU 2016-02 supersedes previous leasing standards . ASU 2016-02 is effective for the Company for reporting periods beginning after December 15, 2018, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-02 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships” (“ASU 2016-05”) which provides guidance clarifying that a novation of party to a derivative instrument, whereby one of the parties to a derivative instrument is replaced with another party, does not, in and of itself, require de-designation of that hedging relationship provided that all other hedge criteria continue to be met. ASU 2016-05 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-05 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”) . ASU 2016-09 is intended to improve the accounting for share-based payments and affects all organizations that issue share-based payment awards to their employees. Several aspects of the accounting for share-based payment awards are simplified with ASU 2016-09, including income tax consequences, classification of awards as equity or liabilities and classification on the statement of cash flows. ASU 2016-09 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The Company is currently assessing the potential impact that the adoption of ASU 2016-09 will have on its consolidated financial statements.

Basis Of Presentation And Sum23

Basis Of Presentation And Summary Of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value	The following table presents the aggregate carrying value of the Company’s indebtedness and the Company’s corresponding estimate of fair value as of March 31, 2016 and December 31, 2015 (in thousands): March 31, 2016 December 31, 2015 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Mortgage notes payable, net $ 3,416,622 $ 3,477,310 $ 3,435,242 $ 3,503,746 Mezzanine notes payable 308,142 306,089 308,482 306,103 Unsecured senior notes, net 6,255,602 6,705,353 5,264,819 5,547,738 Total $ 9,980,366 $ 10,488,752 $ 9,008,543 $ 9,357,587

Investments in Unconsolidated24

Investments in Unconsolidated Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2016
Investments In Unconsolidated Joint Ventures [Abstract]
Investments In Unconsolidated Joint Ventures	The investments in unconsolidated joint ventures consist of the following at March 31, 2016 and December 31, 2015 : Nominal % Ownership Carrying Value of Investment (1) Entity Properties March 31, 2016 December 31, 2015 (in thousands) Square 407 Limited Partnership Market Square North 50.0 % $ (9,506 ) $ (9,951 ) The Metropolitan Square Associates LLC Metropolitan Square 51.0 % 9,238 9,179 BP/CRF 901 New York Avenue LLC 901 New York Avenue 25.0 % (2) (11,617 ) (11,958 ) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.3 % (3) 43,057 43,524 Annapolis Junction NFM, LLC Annapolis Junction 50.0 % (4) (5) 21,134 29,009 540 Madison Venture LLC 540 Madison Avenue 60.0 % 67,715 68,983 500 North Capitol LLC 500 North Capitol Street, NW 30.0 % (3,470 ) (3,292 ) 501 K Street LLC 1001 6th Street 50.0 % (6) 42,540 42,584 Podium Developer LLC The Hub on Causeway 50.0 % 23,881 18,508 1265 Main Office JV LLC 1265 Main Street 50.0 % 16,143 11,916 BNY Tower Holdings LLC Dock72 at the Brooklyn Navy Yard 50.0 % (7) 12,196 11,521 $ 211,311 $ 210,023 _______________ (1) Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015 , respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets. (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 four in-service buildings and two undeveloped land parcels. (5) See Note 13. (6) Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization. (7) Entity is a VIE (See Note 2).
Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block]	The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows: March 31, 2016 December 31, 2015 (in thousands) ASSETS Real estate and development in process, net $ 1,041,533 $ 1,072,412 Other assets 225,200 252,285 Total assets $ 1,266,733 $ 1,324,697 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 829,089 $ 830,125 Other liabilities 38,920 44,549 Members’/Partners’ equity 398,724 450,023 Total liabilities and members’/partners’ equity $ 1,266,733 $ 1,324,697 Company’s share of equity $ 238,166 $ 237,070 Basis differentials (1) (26,855 ) (27,047 ) Carrying value of the Company’s investments in unconsolidated joint ventures (2) $ 211,311 $ 210,023 _______________ (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. (2) Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015 , respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets.
Statements Of Operations Of The Joint Ventures	The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows: For the three months ended March 31, 2016 2015 (in thousands) Total revenue (1) $ 37,669 $ 39,532 Expenses Operating 16,667 16,275 Depreciation and amortization 9,064 9,071 Total expenses 25,731 25,346 Operating income 11,938 14,186 Other expense Interest expense 8,389 7,980 Net income $ 3,549 $ 6,206 Company’s share of net income $ 1,599 $ 14,642 (2) Basis differential 192 192 Income from unconsolidated joint ventures $ 1,791 $ 14,834 _______________ (1) Includes straight-line rent adjustments of approximately $2.2 million and $1.6 million for the three months ended March 31, 2016 and 2015 , respectively. (2) During the three months ended March 31, 2015, the Company received a distribution of approximately $24.5 million , which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10 -year mortgage loan totaling $225.0 million . The Company’s allocation of income and distributions for the three months ended March 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement.

Unsecured Senior Notes (Tables)

Unsecured Senior Notes (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Senior Notes	The following summarizes the unsecured senior notes outstanding as of March 31, 2016 (dollars in thousands): Coupon/ Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 10 Year Unsecured Senior Notes 5.875 % 5.967 % $ 700,000 October 15, 2019 10 Year Unsecured Senior Notes 5.625 % 5.708 % 700,000 November 15, 2020 10 Year Unsecured Senior Notes 4.125 % 4.289 % 850,000 May 15, 2021 7 Year Unsecured Senior Notes 3.700 % 3.853 % 850,000 November 15, 2018 11 Year Unsecured Senior Notes 3.850 % 3.954 % 1,000,000 February 1, 2023 10.5 Year Unsecured Senior Notes 3.125 % 3.279 % 500,000 September 1, 2023 10.5 Year Unsecured Senior Notes 3.800 % 3.916 % 700,000 February 1, 2024 10 Year Unsecured Senior Notes 3.650 % 3.766 % 1,000,000 February 1, 2026 Total principal 6,300,000 Net unamortized discount (13,148 ) Deferred financing costs, net (31,250 ) Total $ 6,255,602 _______________ (1) Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs. (2) No principal amounts are due prior to maturity.

Derivative Instruments and He26

Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	These interest rate swap contracts were entered into in advance of a financing with a target commencement date in June 2017 and maturity in June 2027. Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at March 31, 2016 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 550,000 September 1, 2016 September 1, 2026 2.129 % - 2.571 % Other Liabilities $ (36,561 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 450,000 June 7, 2017 June 7, 2027 2.336 % - 2.950 % Other Liabilities $ (32,387 ) $ 1,000,000 $ (68,948 ) Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2015 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 400,000 September 1, 2016 September 1, 2026 2.348 % - 2.571 % Other Liabilities $ (5,419 ) Interest Rate Swaps 150,000 September 1, 2016 September 1, 2026 2.129 % - 2.325 % Prepaid Expenses and Other Assets 1,188 $ 550,000 $ (4,231 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 250,000 June 7, 2017 June 7, 2027 2.677 % - 2.950 % Other Liabilities $ (7,247 ) Interest Rate Swaps 150,000 June 7, 2017 June 7, 2027 2.336 % - 2.430 % Prepaid Expenses and Other Assets 1,176 $ 400,000 $ (6,071 ) $ 950,000 $ (10,302 )
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the location in the financial statements of the losses recognized related to the Company’s cash flow hedges for the three months ended March 31, 2016 and 2015 : Three months ended 2016 2015 (in thousands) Amount of loss related to the effective portion recognized in other comprehensive loss $ (58,646 ) $ (3,533 ) Amount of loss related to the effective portion subsequently reclassified to earnings (1) $ (627 ) $ (627 ) Amount of gain (loss) related to the ineffective portion and amount excluded from effectiveness testing $ — $ — ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Boston Properties, Inc. The following table reflects the changes in accumulated other comprehensive loss for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ (14,114 ) Effective portion of interest rate contracts (58,646 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 15,427 Balance at March 31, 2016 $ (56,706 ) Balance at December 31, 2014 $ (9,304 ) Effective portion of interest rate contracts (3,533 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 303 Balance at March 31, 2015 $ (11,907 ) ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015. Boston Properties Limited Partnership The following table reflects the changes in accumulated other comprehensive loss for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ (18,337 ) Effective portion of interest rate contracts (58,646 ) Amortization of interest rate contracts (1) 627 Other comprehensive loss attributable to noncontrolling interests 10,526 Balance at March 31, 2016 $ (65,830 ) Balance at December 31, 2014 $ (12,973 ) Effective portion of interest rate contracts (3,533 ) Amortization of interest rate contracts (1) 627 Balance at March 31, 2015 $ (15,879 ) ___________ (1) Consists of amounts from previous interest rate hedging programs entered into prior to 2015.

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Line Items]
Schedule Of redeemable preferred units	The following table reflects the activity of the noncontrolling interests—redeemable preferred units for the three months ended March 31, 2015 (in thousands): Balance at December 31, 2014 $ 633 Net income 3 Distributions (3 ) Balance at March 31, 2015 $ 633
Schedule of Redeemable Interest in Property Partnerships [Table Text Block]	The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company’s Fountain Square consolidated entity for the three months ended March 31, 2015 (in thousands): Balance at December 31, 2014 $ 104,692 Net income 75 Distributions (1,400 ) Adjustment to reflect redeemable interest at redemption value 2,153 Balance at March 31, 2015 $ 105,520
Distributions Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]	The following table presents Boston Properties, Inc.’s dividends per share and Boston Properties Limited Partnership’s distributions per unit for the periods presented: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 31, 2016 April 29, 2016 $0.65 $0.65 December 31, 2015 January 28, 2016 $1.90 (1) $1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/common unit.
Schedule Of Noncontrolling Interest Common Units [Table Text Block]	The following table reflects the activity of noncontrolling interests—redeemable common units of Boston Properties Limited Partnership for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ 2,286,689 Contributions 30,808 Net income 21,393 Distributions (11,865 ) Conversion of redeemable partnership units (446 ) Unearned compensation (22,424 ) Accumulated other comprehensive loss (4,901 ) Adjustment to reflect redeemable partnership units at redemption value 8,218 Balance at March 31, 2016 $ 2,307,472 Balance at December 31, 2014 $ 2,310,046 Contributions 38,371 Net income 20,188 Distributions (11,705 ) Conversion of redeemable partnership units (8,689 ) Unearned compensation (18,597 ) Accumulated other comprehensive loss (303 ) Adjustment to reflect redeemable partnership units at redemption value 211,747 Balance at March 31, 2015 $ 2,541,058
Schedule Of Noncontrolling Interest Property Partnerships [Table Text Block]	The following table reflects the activity of the noncontrolling interests in property partnerships for the three months ended March 31, 2016 and 2015 (in thousands): Balance at December 31, 2015 $ 1,574,400 Capital contributions 2,489 Net income 10,464 Accumulated other comprehensive loss (10,526 ) Distributions (12,915 ) Balance at March 31, 2016 $ 1,563,912 Balance at December 31, 2014 $ 1,602,467 Capital contributions 629 Net income 12,980 Distributions (16,574 ) Balance at March 31, 2015 $ 1,599,502
Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Distributions Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]	The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units and, after the measurement date, the 2013 MYLTIP Units) and its distributions on the 2013 MYLTIP Units (prior to the February 4, 2016 measurement date), 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units (after the February 10, 2016 issuance date) for the periods presented: Record Date Payment Date Distributions on the OP Units and LTIP Units Distributions on MYLTIP Units March 31, 2016 April 29, 2016 $0.65 $0.065 December 31, 2015 January 28, 2016 $1.90 (1) $0.065 _______________ (1) Includes a special distribution of $1.25 per unit.

Stockholders' Equity _ Partne28

Stockholders' Equity / Partners'' Capital Tables (Tables)	3 Months Ended
	Mar. 31, 2016
Class of Stock [Line Items]
Dividends Declared [Table Text Block]	The following table presents Boston Properties, Inc.’s dividends per share and Boston Properties Limited Partnership’s distributions per unit for the periods presented: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) March 31, 2016 April 29, 2016 $0.65 $0.65 December 31, 2015 January 28, 2016 $1.90 (1) $1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/common unit.
Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Dividends Declared [Table Text Block]	The following table presents Boston Properties Inc.’s dividends per share on its outstanding Series B Preferred Stock: Record Date Payment Date Dividend (Per Share) May 5, 2016 May 16, 2016 $32.8125 February 5, 2016 February 16, 2016 $32.8125

Earnings Per Share _ Common U29

Earnings Per Share / Common Unit (Tables)	3 Months Ended
	Mar. 31, 2016
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share	For the three months ended March 31, 2016 Income (Numerator) Shares (Denominator) Per Share Amount (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 153,626 $ 1.18 Allocation of undistributed earnings to participating securities (247 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 181,500 153,626 $ 1.18 Effect of Dilutive Securities: Stock Based Compensation — 291 — Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 181,500 153,917 $ 1.18 For the three months ended March 31, 2015 Income (Numerator) Shares (Denominator) Per Share Amount (in thousands, except for per share amounts) Basic Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 171,182 153,230 $ 1.12 Allocation of undistributed earnings to participating securities (188 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 170,994 153,230 $ 1.12 Effect of Dilutive Securities: Stock Based Compensation — 643 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 170,994 153,873 $ 1.11
Boston Properties Limited Partnership
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share	For the three months ended March 31, 2016 Income (Numerator) Units (Denominator) Per Unit Amount (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 171,309 $ 1.21 Allocation of undistributed earnings to participating securities (275 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,021 171,309 $ 1.21 Effect of Dilutive Securities: Stock Based Compensation — 291 — Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,021 171,600 $ 1.21 For the three months ended March 31, 2015 Income (Numerator) Units (Denominator) Per Unit Amount (in thousands, except for per unit amounts) Basic Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,369 171,084 $ 1.13 Allocation of undistributed earnings to participating securities (210 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,159 171,084 $ 1.13 Effect of Dilutive Securities: Stock Based Compensation — 643 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,159 171,727 $ 1.12

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Schedule Of Segment Information By Geographic Area And Property Type	Information by geographic area and property type (dollars in thousands): For the three months ended March 31, 2016 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 177,827 $ 291,858 $ 76,317 $ 100,488 $ 646,490 Residential 1,171 — — 2,878 4,049 Hotel 8,757 — — — 8,757 Total 187,755 291,858 76,317 103,366 659,296 % of Grand Totals 28.48 % 44.27 % 11.57 % 15.68 % 100.00 % Rental Expenses: Office 70,687 88,798 23,905 34,182 217,572 Residential 520 — — 1,080 1,600 Hotel 7,634 — — — 7,634 Total 78,841 88,798 23,905 35,262 226,806 % of Grand Totals 34.76 % 39.15 % 10.54 % 15.55 % 100.00 % Net operating income $ 108,914 $ 203,060 $ 52,412 $ 68,104 $ 432,490 % of Grand Totals 25.18 % 46.95 % 12.12 % 15.75 % 100.00 % For the three months ended March 31, 2015 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 176,027 $ 253,098 $ 71,911 $ 96,173 $ 597,209 Residential 1,178 — — 5,676 6,854 Hotel 9,085 — — — 9,085 Total 186,290 253,098 71,911 101,849 613,148 % of Grand Totals 30.38 % 41.28 % 11.73 % 16.61 % 100.00 % Rental Expenses: Office 76,451 85,061 22,821 33,471 217,804 Residential 509 — — 3,037 3,546 Hotel 7,576 — — — 7,576 Total 84,536 85,061 22,821 36,508 228,926 % of Grand Totals 36.92 % 37.16 % 9.97 % 15.95 % 100.00 % Net operating income $ 101,754 $ 168,037 $ 49,090 $ 65,341 $ 384,222 % of Grand Totals 26.48 % 43.73 % 12.78 % 17.01 % 100.00 %
Schedule Of Reconciliation Of Net Operating Income To Net Income	Boston Properties, Inc. The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties, Inc. common shareholders: Three months ended 2016 2015 (in thousands) Net Operating Income $ 432,490 $ 384,222 Add: Development and management services income 6,689 5,328 Income from unconsolidated joint ventures 1,791 14,834 Interest and other income 1,505 1,407 Gains from investments in securities 259 393 Gains on sales of real estate 67,623 95,084 Less: General and administrative expense 29,353 28,791 Transaction costs 25 327 Depreciation and amortization expense 159,448 154,223 Interest expense 105,309 108,757 Noncontrolling interests in property partnerships 10,464 15,208 Noncontrolling interest—redeemable preferred units of the Operating Partnership — 3 Noncontrolling interest—common units of the Operating Partnership 21,393 20,188 Preferred dividends 2,618 2,589 Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 $ 171,182 Boston Properties Limited Partnership The following is a reconciliation of Net Operating Income to net income attributable to Boston Properties Limited Partnership common unitholders: Three months ended 2016 2015 (in thousands) Net Operating Income $ 432,490 $ 384,222 Add: Development and management services income 6,689 5,328 Income from unconsolidated joint ventures 1,791 14,834 Interest and other income 1,505 1,407 Gains from investments in securities 259 393 Gains on sales of real estate 69,792 95,084 Less: General and administrative expense 29,353 28,791 Transaction costs 25 327 Depreciation and amortization expense 157,461 152,224 Interest expense 105,309 108,757 Noncontrolling interests in property partnerships 10,464 15,208 Noncontrolling interest—redeemable preferred units — 3 Preferred distributions 2,618 2,589 Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 $ 193,369

Organization (Details)

Organization (Details) ft² in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016ft²aseriesReal_Estate_Propertiesyrshares	Dec. 31, 2015shares
Real Estate Properties [Line Items]
Restriction on redemption of OP units from date of issuance (years) | yr	1
One OP unit is equivalent to one share of Common Stock (in shares) | shares	1
OP unit conversion rate (in shares) | shares	1
Number Of Series Of Preferred Units Outstanding | series	1
Area of undeveloped land parcels owned (in acres) | a	457.1
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	167
Net Rentable Area (in sf) | ft²	46.3
Total Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	11
Net Rentable Area (in sf) | ft²	4.6
Total Office Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	157
Office Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	9
Hotel Property [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Retail Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	5
Residential Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	4
Residential Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	2
Series B Cumulative Redeemable Preferred Stock [Member]
Real Estate Properties [Line Items]
Ratio of depository shares to shares of Series B Preferred Stock	0.01
Series B, Shares Outstanding (in shares) | shares	80,000	80,000
Series B, Dividend Rate, Percentage	5.25%
Depository shares of Series B Cumulative Redeemable Preferred [Member]
Real Estate Properties [Line Items]
Series B, Shares Outstanding (in shares) | shares	8,000,000
Series B Preferred Units [Member]
Real Estate Properties [Line Items]
Series B, Shares Outstanding (in shares) | shares	80,000
Boston Properties Inc
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership (percent)	89.40%	89.50%

Basis Of Presentation And Sum32

Basis Of Presentation And Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Mortgages [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	$ 3.2	$ 3.5
Unsecured Debt [Member]
Debt Instrument [Line Items]
Deferred Finance Costs, Net	$ 31.3	$ 24.5

Basis Of Presentation And Sum33

Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 3,416,622	$ 3,435,242
Mezzanine notes payable	308,142	308,482
Unsecured senior notes, net	6,255,602	5,264,819
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	3,477,310	3,503,746
Mezzanine notes payable	306,089	306,103
Unsecured senior notes, net	6,705,353	5,547,738
Total	10,488,752	9,357,587
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	3,416,622	3,435,242
Mezzanine notes payable	308,142	308,482
Unsecured senior notes, net	6,255,602	5,264,819
Total	$ 9,980,366	$ 9,008,543

Real Estate Activity During t34

Real Estate Activity During the Three Months Ended March 31, 2016 (Narrative) (Details) $ in Thousands	Feb. 03, 2016USD ($)ft²	Feb. 01, 2016USD ($)ft²	Jan. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)
Real Estate Properties [Line Items]
Net income				$ 250,353	$ 206,209
Proceeds from sales of real estate				104,816	194,821
Gains on sales of real estate				67,623	95,084
Revenues				665,985	618,476
415 Main Street [Member]
Real Estate Properties [Line Items]
Net income			$ 1,200		2,600
Sale Price Of Sold Property		$ 105,400
Proceeds from sales of real estate		$ 104,900
Net Rentable Area (in sf) | ft²		231,000
Terminated lease at 250 West 55thStreet in NYC [Member]
Real Estate Properties [Line Items]
Net Rentable Area (in sf) | ft²	85,000
Revenues	$ 45,000
Boston Properties Inc | 415 Main Street [Member]
Real Estate Properties [Line Items]
Gains on sales of real estate		$ 60,800
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
Net income				252,340	208,208
Proceeds from sales of real estate				104,816	194,821
Gains on sales of real estate				69,792	95,084
Revenues				$ 665,985	$ 618,476
Boston Properties Limited Partnership | 415 Main Street [Member]
Real Estate Properties [Line Items]
Gains on sales of real estate		$ 63,000

Investments in Unconsolidated35

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2016USD ($)ft²Land_ParcelsBuildingspayments	Dec. 31, 2015USD ($)
Schedule of Equity Method Investments [Line Items]
Carrying value of the Company's investments in unconsolidated joint ventures		$ 235,904	$ 235,224
Square 407 Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Market Square North
Ownership Percentage		50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ (9,506)	(9,951)
The Metropolitan Square Associates LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Metropolitan Square
Ownership Percentage		51.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 9,238	9,179
BP/CRF 901 New York Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		901 New York Avenue
Ownership Percentage	[2]	25.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ (11,617)	(11,958)
WP Project Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Wisconsin Place Land and Infrastructure
Ownership Percentage	[3]	33.30%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 43,057	43,524
Entity Owning Land And Infrastructure Of Project [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		33.30%
Annapolis Junction NFM, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Annapolis Junction
Ownership Percentage	[4],[5]	50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 21,134	29,009
Number of real estate properties | Buildings		4
Parcels of undeveloped land | Land_Parcels		2
540 Madison Venture LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		540 Madison Avenue
Ownership Percentage		60.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 67,715	68,983
500 North Capitol LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		500 North Capitol Street, NW
Ownership Percentage		30.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ (3,470)	(3,292)
501 K Street LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		1001 6th Street
Ownership Percentage	[6]	50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 42,540	42,584
Potential additonal payments to joint venture partner | payments		2
Minimum square footage to make a potential additional payment to joint venture partner (in sqft) | ft²		520,000
Podium Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		The Hub on Causeway
Ownership Percentage		50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 23,881	18,508
1265 Main Office JV LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		1265 Main Street
Ownership Percentage		50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 16,143	11,916
BNY Tower Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Dock72 at the Brooklyn Navy Yard
Ownership Percentage	[7]	50.00%
Carrying value of the Company's investments in unconsolidated joint ventures	[1]	$ 12,196	11,521
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value of the Company's investments in unconsolidated joint ventures		(24,600)	(25,200)
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Carrying value of the Company's investments in unconsolidated joint ventures	[1],[8]	$ 211,311	$ 210,023
[1]	Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015, respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets.
[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]	See Note 13.
[5]	The joint venture owns four in-service buildings and two undeveloped land parcels.
[6]	Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
[7]	Entity is a VIE (See Note 2).
[8]	(2)Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015, respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets.

Investments in Unconsolidated36

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
ASSETS
Real estate and development in process, net		$ 15,569,424	$ 15,555,641
Liabilities and Members'/Partners' Equity [Abstract]
Mortgage notes payable, net		3,416,622	3,435,242
Other Liabilities		498,290	483,601
Total liabilities and equity / capital		19,175,830	18,351,486
Carrying value of the Company's investments in unconsolidated joint ventures		235,904	235,224
Unconsolidated Joint Ventures [Member]
ASSETS
Real estate and development in process, net		1,041,533	1,072,412
Other assets		225,200	252,285
Total assets		1,266,733	1,324,697
Liabilities and Members'/Partners' Equity [Abstract]
Mortgage notes payable, net		829,089	830,125
Other Liabilities		38,920	44,549
Members'/Partners' equity		398,724	450,023
Total liabilities and equity / capital		1,266,733	1,324,697
Company's share of equity		238,166	237,070
Basis differentials	[1]	(26,855)	(27,047)
Carrying value of the Company's investments in unconsolidated joint ventures	[2],[3]	211,311	210,023
Unconsolidated Joint Ventures [Member]
Liabilities and Members'/Partners' Equity [Abstract]
Carrying value of the Company's investments in unconsolidated joint ventures		$ (24,600)	$ (25,200)
[1]	(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.
[2]	(2)Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015, respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets.
[3]	Investments with deficit balances aggregating approximately $24.6 million and $25.2 million at March 31, 2016 and December 31, 2015, respectively, have been reflected within Other Liabilities on the Company’s Consolidated Balance Sheets.

Investments in Unconsolidated37

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015		Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Total revenue		$ 665,985	$ 618,476
Expenses
Depreciation and amortization		159,448	154,223
Total expenses		415,632	412,267
Operating income		250,353	206,209
Other expense
Interest expense		105,309	108,757
Net income		216,222	209,170
Income from unconsolidated joint ventures		1,791	14,834
Distribution related to excess loan proceeds		0	24,527
Mortgage loan		3,416,622			$ 3,435,242
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Total revenue	[1]	37,669	39,532
Expenses
Operating		16,667	16,275
Depreciation and amortization		9,064	9,071
Total expenses		25,731	25,346
Operating income		11,938	14,186
Other expense
Interest expense		8,389	7,980
Net income		3,549	6,206
Company's share of net income		1,599	14,642	[2]
Basis differential		192	192
Income from unconsolidated joint ventures		1,791	14,834
Straight-line rent adjustments		2,200	1,600
Mortgage loan		$ 829,089			$ 830,125
BP/CRF 901 New York Avenue LLC [Member]
Other expense
Distribution related to excess loan proceeds			24,500
Mortgage loan			$ 225,000
[1]	Includes straight-line rent adjustments of approximately $2.2 million and $1.6 million for the three months ended March 31, 2016 and 2015, respectively.
[2]	During the three months ended March 31, 2015, the Company received a distribution of approximately $24.5 million, which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10-year mortgage loan totaling $225.0 million. The Company’s allocation of income and distributions for the three months ended March 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement.

Unsecured Senior Notes Schedule

Unsecured Senior Notes Schedule of Unsecured Senior Notes (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Jan. 20, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total		$ 6,255,602			$ 5,264,819
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Total		6,255,602			$ 5,264,819
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Principal Amount		6,300,000
Net unamortized discount		(13,148)
Deferred Finance Costs, Net		(31,250)
Total		$ 6,255,602
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 5.967%
Debt Instrument [Line Items]
Coupon/Stated Rate		5.875%
Effective Rate	[1]	5.967%
Principal Amount		$ 700,000
Maturity Date	[2]	Oct. 15, 2019
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 5.708%
Debt Instrument [Line Items]
Coupon/Stated Rate		5.625%
Effective Rate	[1]	5.708%
Principal Amount		$ 700,000
Maturity Date	[2]	Nov. 15, 2020
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 4.289%
Debt Instrument [Line Items]
Coupon/Stated Rate		4.125%
Effective Rate	[1]	4.289%
Principal Amount		$ 850,000
Maturity Date	[2]	May 15, 2021
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.853%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.70%
Effective Rate	[1]	3.853%
Principal Amount		$ 850,000
Maturity Date	[2]	Nov. 15, 2018
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.954%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.85%
Effective Rate	[1]	3.954%
Principal Amount		$ 1,000,000
Maturity Date	[2]	Feb. 1, 2023
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.279%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.125%
Effective Rate	[1]	3.279%
Principal Amount		$ 500,000
Maturity Date	[2]	Sep. 1, 2023
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.916%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.80%
Effective Rate	[1]	3.916%
Principal Amount		$ 700,000
Maturity Date	[2]	Feb. 1, 2024
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.766%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.65%		3.65%
Effective Rate		3.766%	[1]	3.766%
Principal Amount		$ 1,000,000		$ 1,000,000
Maturity Date	[2]	Feb. 1, 2026
[1]	Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.
[2]	No principal amounts are due prior to maturity.

Unsecured Senior Notes Unsecu39

Unsecured Senior Notes Unsecured Senior Notes (Narrative) (Details) - USD ($) $ in Thousands	Jan. 20, 2016	Mar. 31, 2016		Mar. 31, 2015
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt		$ 997,080		$ 0
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Proceeds from Issuance of Unsecured Debt		$ 997,080		$ 0
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Maximum Leverage Ratio		60.00%
Maximum Secured Debt Leverage Ratio		50.00%
Minimum Interest Coverage Ratio		1.50
Minimum Unencumbered Asset Value Percentage Of Unsecured Debt		150.00%
Principal Amount		$ 6,300,000
Unsecured Senior Notes 3.766% | Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Principal Amount	$ 1,000,000	$ 1,000,000
Coupon/Stated Rate	3.65%	3.65%
Senior Notes Pricing	99.708%
Effective Rate	3.766%	3.766%	[1]
Proceeds from Issuance of Unsecured Debt	$ 988,900
[1]	Yield on issuance date including the effects of discounts on the notes and the amortization of financing costs.

Derivative Instruments and He40

Derivative Instruments and Hedging Activities (Details) $ in Thousands	Jan. 06, 2016USD ($)swaps	Mar. 31, 2016USD ($)yrswaps	Dec. 31, 2015USD ($)
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value		$ 69,300
Assets Needed for Immediate Settlement, Aggregate Fair Value		69,300
Amount of loss related to the effective portion recognized in other comprehensive loss		68,900
Notional Amount		1,000,000	$ 950,000
Estimated current balance held in Accumulated Other Comprehensive Loss to be reclassified into earnings within the next twelve months		$ (2,100)
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Number of interest rate swap agreements entered into (swap contracts) | swaps		17
Term of anticipated mortgage loan (in years) | yr		10
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr		10
Average Fixed Interest Rate		2.423%
Notional Amount		$ 550,000	550,000
767 Fifth Partners LLC [Member]
Debt Instrument [Line Items]
Ownership Percentage by the Company		60.00%
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Number of interest rate swap agreements entered into (swap contracts) | swaps	2	16
Term of anticipated mortgage loan (in years) | yr		10
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr		10
Average Fixed Interest Rate		2.619%
Notional Amount	$ 50,000	$ 450,000	$ 400,000

Derivative Instruments and He41

Derivative Instruments and Hedging Activities Derivative Instrument and Hedging Activities Notional Table (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Jan. 06, 2016
Derivative [Line Items]
Fair Value	$ (58,646)	$ (3,533)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	1,000,000		$ 950,000
Fair Value	(68,948)		(10,302)
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	550,000		550,000
Fair Value	(36,561)		(4,231)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.129% - 2.571% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount	$ 550,000
Derivative, Lower Fixed Interest Rate Range	2.129%
Derivative, Higher Fixed Interest Rate Range	2.571%
Fair Value	$ (36,561)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.348% - 2.571% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount			$ 400,000
Derivative, Lower Fixed Interest Rate Range			2.348%
Derivative, Higher Fixed Interest Rate Range			2.571%
Fair Value			$ (5,419)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.129% - 2.325% [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount			$ 150,000
Derivative, Lower Fixed Interest Rate Range			2.129%
Derivative, Higher Fixed Interest Rate Range			2.325%
Fair Value			$ 1,188
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	450,000		400,000	$ 50,000
Fair Value	(32,387)		(6,071)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.336% - 2.950% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount	$ 450,000
Derivative, Lower Fixed Interest Rate Range	2.336%
Derivative, Higher Fixed Interest Rate Range	2.95%
Fair Value	$ (32,387)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.677% - 2.950% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount			$ 250,000
Derivative, Lower Fixed Interest Rate Range			2.677%
Derivative, Higher Fixed Interest Rate Range			2.95%
Fair Value			$ (7,247)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.336% - 2.430% [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount			$ 150,000
Derivative, Lower Fixed Interest Rate Range			2.336%
Derivative, Higher Fixed Interest Rate Range			2.43%
Fair Value			$ 1,176

Derivative Instruments and He42

Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Gain or Loss Recognized Related to Cash Flow hedges (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Derivative [Line Items]
Amount of loss related to the effective portion recognized in other comprehensive loss		$ (58,646)	$ (3,533)
Amount of loss related to the effective portion subsequently reclassified to earnings (1)	[1]	(627)	(627)
Amount of gain (loss) related to the ineffective portion and amount excluded from effectiveness testing		$ 0	$ 0
[1]	Consists of amounts from previous interest rate hedging programs entered into prior to 2015.

Derivative Instruments and He43

Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Accumulated Other Comprehensive Income or Loss [Roll Forward]
Beginning Balance		$ (14,114)	$ (9,304)	$ (9,304)
Effective portion of interest rate contracts		(58,646)	(3,533)
Amortization of interest rate contracts	[1],[2]	627	627
Other comprehensive loss attributable to noncontrolling interests		15,427	303
Ending Balance		(56,706)	(11,907)	(14,114)
Boston Properties Limited Partnership
Accumulated Other Comprehensive Income or Loss [Roll Forward]
Beginning Balance		(18,337)	(12,973)	(12,973)
Effective portion of interest rate contracts		(58,646)	(3,533)
Amortization of interest rate contracts	[2],[3]	627	627
Comprehensive loss attributable to noncontrolling interests		10,526
Ending Balance		$ (65,830)	$ (15,879)	$ (18,337)
[1]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties, Inc.’s Consolidated Statements of Operations.
[2]	Consists of amounts from previous interest rate hedging programs entered into prior to 2015.
[3]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties Limited Partnership's Consolidated Statements of Operations.

Commitments And Contingencies (

Commitments And Contingencies (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2009	Dec. 31, 2015	Mar. 11, 2015	Dec. 31, 2014	Jan. 10, 2014
Commitments And Contingencies [Line Items]
Letter of credit and performance obligations	$ 22.5
Property insurance program per occurrence limits	1,000
Per occurrence limit for NBCR Coverage	1,000
Value of program trigger	$ 120
Coinsurance of program trigger	16.00%
Deductible in insurance as a percentage of the value of the affected property, San Francisco	3.00%
Per occurrence limit of the earthquake insurance which covers San Francisco region	$ 170
Annual aggregate limit of the earthquake insurance which covers San Francisco region	170
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco	20
Earthquake Coverage Included In Builders Risk Policy For Salesforce Tower	60
767 Venture, LLC [Member]
Commitments And Contingencies [Line Items]
Maximum funding obligation	$ 16.2
Ownership Percentage by the Company	60.00%
Property insurance program per occurrence limits	$ 1,625
Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, amount filed by general creditor		$ 45.3
Bankruptcy claim amount allowed by court to creditor						$ 45.2
Bankruptcy Claims, Amount of Claims Settled			$ 8.1	$ 4.5	$ 7.7
Bankruptcy remaining claim amount allowed by court to creditor	29.4
Fountain Square [Member]
Commitments And Contingencies [Line Items]
Guarantee Obligation Related To Tenant Re-Leasing Costs	0.7
601 Lexington Avenue [Member]
Commitments And Contingencies [Line Items]
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	250
Boston Properties Limited Partnership
Commitments And Contingencies [Line Items]
Operating partnership guarantee to cover liabilities of IXP	$ 20

Noncontrolling Interests (Narra

Noncontrolling Interests (Narrative) (Details)	Mar. 31, 2016shares
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Operating Partnership (OP) Units (in shares)	16,092,449
Long-Term Incentive Plan (LTIP) Units (in shares)	2,065,185
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	215,709
2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2013 MYLTIP (in units)	103,882
Boston Properties Limited Partnership | MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIP (in units)	475,558
Boston Properties Limited Partnership | 2015 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS (in units)	367,936
Boston Properties Limited Partnership | 2016 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIPs (in units)	474,456

Noncontrolling Interests (Redee

Noncontrolling Interests (Redeemable Preferred Units) (Narrative) (Details) - Series Four Preferred Units [Member] - Noncontrolling Interests [Member] $ / shares in Units, $ in Millions	Jun. 25, 2015USD ($)$ / sharesshares
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Preferred Units Liquidation Preference | $ / shares	$ 50
Series Four Preferred Units Redeemed (in shares) | shares	12,667
Redemption of Series Four Preferred Units | $	$ 0.6
Series Four Preferred Units Annual Dividend Payable Rate	2.00%

Noncontrolling Interests (Red47

Noncontrolling Interests (Redeemable Preferred Units) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Activity of Noncontrolling Interests [Roll Forward]
Net Income	$ 0	$ (3)
Redeemable Preferred Units [Member]
Activity of Noncontrolling Interests [Roll Forward]
Beginning Balance		633
Net Income		3
Distributions		(3)
Ending Balance		$ 633

Noncontrolling Interests Redeem

Noncontrolling Interests Redeemable interest in property partnership (Narrative) (Details) - Fountain Square [Member] - USD ($) $ in Millions	Sep. 15, 2015	Aug. 06, 2015	Oct. 04, 2012
Noncontrolling Interest [Line Items]
Aggregate purchase price			$ 385
Indebtedness assumed			$ 211.3
Ownership Percentage	50.00%	50.00%	50.00%
Fixed Price to Acquire Remaining Portion of Joint venture		$ 100.9
Payments to Acquire Businesses, Gross			$ 87
Ownership Percentage by the Company			50.00%
Future Fixed Price to Acquire Remaining Portion of Joint venture			$ 102
Fixed Price Option Expiration Date			Jan. 31, 2016
Payments for Repurchase of Redeemable Noncontrolling Interest	$ 100.9
Mortgage debt assumed upon acquisition of noncontrolling interest	$ 105.6

Noncontrolling Interests Noncon

Noncontrolling Interests Noncontrolling Redeemable Property Partnerships (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2015USD ($)
Noncontrolling Interest Redeemable Property Partnership [Abstract]
Beginning Balance	$ 104,692
Net income	75
Distributions	(1,400)
Adjustment to Reflect Redeemable Interest at Redemption Value	2,153
Ending Balance	$ 105,520

(Common Units) (Narrative) (Det

(Common Units) (Narrative) (Details) $ / shares in Units, $ in Millions	Feb. 04, 2016USD ($)shares	Feb. 06, 2015USD ($)shares	Mar. 31, 2016USD ($)yr$ / sharesshares
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)			13,259
Redemption of OP units issued on conversion of LTIP Units (in shares)			7,277
Restriction on redemption of OP Unit to Common Stock (in years) | yr			1
Redemption of OP Unit equivalence to Common Stock (in shares)			1
Common units of operating partnership if converted value | $			$ 2,300
Closing price of common stock (in dollars per share) | $ / shares			$ 127.08
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards earned | $		$ 32.1
Potential maximum amount of Outperformance Awards earned (percent)		80.00%
Potential Awards Earned | $		$ 40
2012 OPP Units Forfeited		174,549
2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	109.50%
Value of MYLTIP Awards | $	$ 13.5
2013 MYLTIP Units Forfeited	205,762
Boston Properties Limited Partnership | OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance Awards LTIP Units distribution as percentage of OP Unit distribution prior to measurement date			10.00%
Boston Properties Limited Partnership | MYLTIP 2014 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIP (in units)			475,558
Boston Properties Limited Partnership | 2015 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS (in units)			367,936
Boston Properties Limited Partnership | 2016 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIPs (in units)			474,456

Noncontrolling Interests Common

Noncontrolling Interests Common units distributions (Details) - $ / shares		Jan. 28, 2016	Mar. 09, 2016
special dividend [Member]
Dividends Payable [Line Items]
Distributions Declared To OP And LTIP Units Per Unit (in dollars per unit)		$ 1.25
Boston Properties Limited Partnership
Dividends Payable [Line Items]
Distributions Declared To OP And LTIP Units Per Unit (in dollars per unit)			$ 0.65
Distributions Declared To MYLTIP Units Per Unit (in dollars per unit)			$ 0.065
Distributions made to OP and LTIP units per unit (in dollars per unit)	[1]	1.90
Distribution paid to outperformance awards, MYLTIP Units (in dollars per unit)		$ 0.065
[1]	Includes a special distribution of $1.25 per unit.

Noncontrolling Interests Comm52

Noncontrolling Interests Common units for Boston Properties LImited Partnership (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Conversion of redeemable partnership units		$ 0
Accumulated other comprehensive loss	$ (56,706)	(11,907)	$ (14,114)	$ (9,304)
Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Conversion of redeemable partnership units	438	(5,162)
Boston Properties Limited Partnership
Noncontrolling Interest [Line Items]
Accumulated other comprehensive loss	(65,830)	(15,879)	$ (18,337)	$ (12,973)
Boston Properties Limited Partnership | Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Beginning balance	2,286,689	2,310,046
Contributions	30,808	38,371
Net Income	21,393	20,188
Distributions	(11,865)	(11,705)
Conversion of redeemable partnership units	(446)	(8,689)
Unearned Compensation	(22,424)	(18,597)
Accumulated other comprehensive loss	(4,901)	(303)
Adjustments To Reflect Redeemable Preferred Units At Redemption Value	8,218	211,747
Ending balance	$ 2,307,472	$ 2,541,058

Noncontrolling Interests (Prope

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) $ in Thousands	Sep. 18, 2015USD ($)ft²	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)
Noncontrolling Interest [Line Items]
Proceeds from sales of real estate		$ 104,816	$ 194,821
Property partnerships		1,563,912		$ 1,574,400
Gains on sales of real estate		67,623	95,084
505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Proceeds from sales of real estate	$ 194,600
Ownership Percentage by the Company	50.00%
Sale Price Of Sold Property	$ 318,000
Mortgage notes payable assigned in connection with the sale of real estate	$ 117,000
Net Rentable Area (in sf) | ft²	322,000
Gains on sales of real estate	$ 199,500
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | 505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Proceeds from sales of real estate	97,300
Gains on sales of real estate	101,100
Boston Properties Limited Partnership
Noncontrolling Interest [Line Items]
Proceeds from sales of real estate		104,816	194,821
Gains on sales of real estate		$ 69,792	$ 95,084
Boston Properties Limited Partnership | 505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Gains on sales of real estate	$ 199,700

Noncontrolling Interests Proper

Noncontrolling Interests Property Partnerships (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Activity of Noncontrolling Interests [Roll Forward]
Beginning Balance	$ 1,574,400
Capital contributions	(2,489)	$ (629)
Net income	(10,464)	(15,208)
Accumulated other comprehensive loss	15,427	303
Ending Balance	1,563,912
Property Partnerships Member
Activity of Noncontrolling Interests [Roll Forward]
Beginning Balance	1,574,400	1,602,467
Capital contributions	2,489	629
Net income	10,464	12,980
Accumulated other comprehensive loss	(10,526)
Distributions	(12,915)	(16,574)
Ending Balance	$ 1,563,912	$ 1,599,502

Stockholders' Equity _ Partne55

Stockholders' Equity / Partners'' Capital Narrative (Details)	Jun. 03, 2014USD ($)yr	Mar. 31, 2016USD ($)$ / sharesshares	Mar. 27, 2018$ / shares	Dec. 31, 2015USD ($)$ / sharesshares
Class of Stock [Line Items]
Common stock, shares outstanding		153,604,966		153,579,966
Shares of Common Stock in connection with the redemption of an equal number of OP Units (in shares)		13,259
Common Stock, Value, Issued | $		$ 1,536,000		$ 1,536,000
Atm Program [Member]
Class of Stock [Line Items]
At the market stock offering program, aggregate value of common stock | $	$ 600,000,000
At Market Stock Offering Program Maximum Length Of Sale In Years | yr	3
Common Stock, Value, Issued | $		$ 0
Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		80,000		80,000
Series B, Dividend Rate, Percentage		5.25%
Series B, Liquidation Preference Per Share (dollars per share) | $ / shares		$ 2,500		$ 2,500
Ratio of depository shares to shares of Series B Preferred Stock		0.01
Depository shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		8,000,000
Series B, Liquidation Preference Per Share (dollars per share) | $ / shares		$ 25
Subsequent Event [Member] | Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Series B, Liquidation Preference Per Share (dollars per share) | $ / shares			$ 2,500
Subsequent Event [Member] | Depository shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Series B, Liquidation Preference Per Share (dollars per share) | $ / shares			$ 25
Boston Properties Limited Partnership
Class of Stock [Line Items]
General Partners' Capital Account, Units Outstanding		1,717,626		1,715,092
Limited Partners' Capital Account, Units Outstanding		151,887,340		151,864,874
Boston Properties Limited Partnership | Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		80,000		80,000
Series B, Liquidation Preference Per Share (dollars per share) | $ / shares		$ 2,500		$ 2,500

Stockholders' Equity _ Partne56

Stockholders' Equity / Partners'' Capital Stockholders' Equity / Partners' Capital Dividends / Distributions (Details) - $ / shares		Feb. 16, 2016	Jan. 28, 2016	Mar. 09, 2016
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit				$ 0.65
Dividends, Per Share / Unit	[1]		$ 1.90
Special dividend / distribution (per share / common unit amount)			1.25
Boston Properties Limited Partnership
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit				0.65
Dividends, Per Share / Unit	[1]		1.90
Special dividend / distribution (per share / common unit amount)			$ 1.25
Series B Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit				$ 32.8125
Dividends, Per Share / Unit		$ 32.8125
[1]	Includes a special dividend/distribution of $1.25 per share/common unit.

Earnings Per Share _ Common U57

Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 181,747	$ 171,182
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	153,626,000	153,230,000
Net income (in dollars per share / unit)	$ 1.18	$ 1.12
Allocation of undistributed earnings to participating securities	$ (247)	$ (188)
Allocation of undistributed earnings to participating securities (in shares / units)	0	0
Allocation of undistributed earnings to participating securities (per share / unit)	$ 0	$ 0
Net income attributable to the Company's common shareholders / unitholders	$ 181,500	$ 170,994
Net income attributable to the Company'scommon shareholders / unitholders(in shares / units)	153,626,000	153,230,000
Net income attributable tothe Company's common shareholders / unitholders (in dollars per share / unit)	$ 1.18	$ 1.12
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)	291,000	643,000
Stock Based Compensation, Per Share / Unit Amount (in dollars per share / unit)	$ 0	$ (0.01)
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 181,500	$ 170,994
Net income attributable to the Company's common shareholders / unitholders (in shares / units) (Denominator)	153,917,000	153,873,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 1.18	$ 1.11
Boston Properties Limited Partnership
Entity Information [Line Items]
Redeemable Common Units	17,683,000	17,854,000
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 207,296	$ 193,369
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	171,309,000	171,084,000
Net income (in dollars per share / unit)	$ 1.21	$ 1.13
Allocation of undistributed earnings to participating securities	$ (275)	$ (210)
Allocation of undistributed earnings to participating securities (in shares / units)	0	0
Allocation of undistributed earnings to participating securities (per share / unit)	$ 0	$ 0
Net income attributable to the Company's common shareholders / unitholders	$ 207,021	$ 193,159
Net income attributable to the Company'scommon shareholders / unitholders(in shares / units)	171,309,000	171,084,000
Net income attributable tothe Company's common shareholders / unitholders (in dollars per share / unit)	$ 1.21	$ 1.13
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)	291,000	643,000
Stock Based Compensation, Per Share / Unit Amount (in dollars per share / unit)	$ 0	$ (0.01)
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 207,021	$ 193,159
Net income attributable to the Company's common shareholders / unitholders (in shares / units) (Denominator)	171,600,000	171,727,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 1.21	$ 1.12

Stock Option and Incentive Pl58

Stock Option and Incentive Plan Stock Option and Incentive Plan (Narrative) (Details)	Feb. 04, 2016USD ($)shares	Jan. 25, 2016USD ($)yrindicestiers	Feb. 06, 2015USD ($)shares
2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
TSR Measurement, Years | yr		3
Indices Used to Compare TSR | indices		2
Number of Tiers | tiers		3
Percentage of annualized TSR 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		$ 17,300,000
MYLTIP Value Amortized Into Earnings, Years | yr		4
OPP Units 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned			$ 40,000,000
2012 OPP Units Forfeited | shares			174,549
Outperformance awards earned			$ 32,100,000
Potential maximum amount of Outperformance Awards earned (percent)			80.00%
2013 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of MYLTIP Awards	$ 13,500,000
Final awards percentage of target	109.50%
2013 MYLTIP Units Forfeited | shares	205,762
Cohen & Steers Realty Majors Portfolio Index [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
NAREIT Office Index adjusted [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
Threshold [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier		$ 9,900,000
Target [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier		19,700,000
High [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount of Each Tier		49,300,000
Maximum [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned		49,300,000
Minimum [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned		$ 0
MYLTIP vesting 2019 [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		50.00%
MYLTIP vesting 2020 [Member] | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		50.00%

Stock Option and Incentive Pl59

Stock Option and Incentive Plan (Restricted Stock) (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)VestingInstallments$ / sharesshares	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued | shares	153,683,866		153,658,866
Stock based Compensation Expense	$ 9,400	$ 10,100
Common Stock, Value, Issued	$ 1,536		$ 1,536
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued | shares	18,521
Employee and director payment per share (in dollars per share) | $ / shares	$ 0.01
Common Stock, Value, Issued	$ 2,100
Employee's weighted average cost per share (in dollars per share) | $ / shares	$ 111.14
LTIPs (including vested MYLTIPS) And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting annual installments | VestingInstallments	4
Unrecognized compensation expenses	$ 30,400
Unvested MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	$ 29,600
Weighted-average period (years)	2 years 10 months 24 days
Boston Properties Limited Partnership | LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares) | shares	139,435
Value of LTIP units issued	$ 14,400
Per unit fair value weighted-average (in dollars per share) | $ / shares	$ 103.26
Expected life assumed to calculate per unit fair value per LTIP unit (years)	5 years 8 months 12 days
Risk-free rate	1.61%
Expected price volatility	33.00%
Boston Properties Limited Partnership | 2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued (in shares) | shares	475,004
Boston Properties Limited Partnership | LTIPs and 2016 MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share) | $ / shares	$ 0.25

Segment Information (Schedule O

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Rental Revenue: Office	$ 646,490	$ 597,209
Rental Revenue: Residential	4,049	6,854
Rental Revenue: Hotel	8,757	9,085
Total revenue	$ 659,296	$ 613,148
Rental Revenue: % of Grand Totals	100.00%	100.00%
Rental Expenses: Office	$ 217,572	$ 217,804
Rental Expenses: Residential	1,600	3,546
Rental Expenses: Hotel	7,634	7,576
Rental Expenses: Total	$ 226,806	$ 228,926
Rental Expenses: % Of Grand Totals	100.00%	100.00%
Net operating Income	$ 432,490	$ 384,222
Net operating Income: % of Grand Totals	100.00%	100.00%
Boston [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Office	$ 177,827	$ 176,027
Rental Revenue: Residential	1,171	1,178
Rental Revenue: Hotel	8,757	9,085
Total revenue	$ 187,755	$ 186,290
Rental Revenue: % of Grand Totals	28.48%	30.38%
Rental Expenses: Office	$ 70,687	$ 76,451
Rental Expenses: Residential	520	509
Rental Expenses: Hotel	7,634	7,576
Rental Expenses: Total	$ 78,841	$ 84,536
Rental Expenses: % Of Grand Totals	34.76%	36.92%
Net operating Income	$ 108,914	$ 101,754
Net operating Income: % of Grand Totals	25.18%	26.48%
New York [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Office	$ 291,858	$ 253,098
Rental Revenue: Residential	0	0
Rental Revenue: Hotel	0	0
Total revenue	$ 291,858	$ 253,098
Rental Revenue: % of Grand Totals	44.27%	41.28%
Rental Expenses: Office	$ 88,798	$ 85,061
Rental Expenses: Residential	0	0
Rental Expenses: Hotel	0	0
Rental Expenses: Total	$ 88,798	$ 85,061
Rental Expenses: % Of Grand Totals	39.15%	37.16%
Net operating Income	$ 203,060	$ 168,037
Net operating Income: % of Grand Totals	46.95%	43.73%
San Francisco [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Office	$ 76,317	$ 71,911
Rental Revenue: Residential	0	0
Rental Revenue: Hotel	0	0
Total revenue	$ 76,317	$ 71,911
Rental Revenue: % of Grand Totals	11.57%	11.73%
Rental Expenses: Office	$ 23,905	$ 22,821
Rental Expenses: Residential	0	0
Rental Expenses: Hotel	0	0
Rental Expenses: Total	$ 23,905	$ 22,821
Rental Expenses: % Of Grand Totals	10.54%	9.97%
Net operating Income	$ 52,412	$ 49,090
Net operating Income: % of Grand Totals	12.12%	12.78%
Washington, DC [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Office	$ 100,488	$ 96,173
Rental Revenue: Residential	2,878	5,676
Rental Revenue: Hotel	0	0
Total revenue	$ 103,366	$ 101,849
Rental Revenue: % of Grand Totals	15.68%	16.61%
Rental Expenses: Office	$ 34,182	$ 33,471
Rental Expenses: Residential	1,080	3,037
Rental Expenses: Hotel	0	0
Rental Expenses: Total	$ 35,262	$ 36,508
Rental Expenses: % Of Grand Totals	15.55%	15.95%
Net operating Income	$ 68,104	$ 65,341
Net operating Income: % of Grand Totals	15.75%	17.01%

Segment Information (Schedule61

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	$ 250,353	$ 206,209
Development and management services income	6,689	5,328
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
General and administrative expense	29,353	28,791
Transaction costs	25	327
Depreciation and amortization expense	159,448	154,223
Interest expense	105,309	108,757
Noncontrolling interest in property partnerships	10,464	15,208
Noncontrolling interest-redeemable preferred units	0	3
Noncontrolling interest-common units of the Operating Partnership	21,393	20,188
Preferred dividends / distributions	2,618	2,589
Net income attributable to the Company's common shareholders / unitholders	181,747	171,182
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	432,490	384,222
Development and management services income	6,689	5,328
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
Gains on sales of real estate	67,623	95,084
General and administrative expense	29,353	28,791
Transaction costs	25	327
Depreciation and amortization expense	159,448	154,223
Interest expense	105,309	108,757
Noncontrolling interest in property partnerships	10,464	15,208
Noncontrolling interest-redeemable preferred units	0	3
Noncontrolling interest-common units of the Operating Partnership	21,393	20,188
Preferred dividends / distributions	2,618	2,589
Net income attributable to the Company's common shareholders / unitholders	181,747	171,182
Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	252,340	208,208
Development and management services income	6,689	5,328
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
General and administrative expense	29,353	28,791
Transaction costs	25	327
Depreciation and amortization expense	157,461	152,224
Interest expense	105,309	108,757
Noncontrolling interest in property partnerships	10,464	15,208
Noncontrolling interest-redeemable preferred units	0	3
Preferred dividends / distributions	2,618	2,589
Net income attributable to the Company's common shareholders / unitholders	207,296	193,369
Boston Properties Limited Partnership | Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net Operating Income	432,490	384,222
Development and management services income	6,689	5,328
Income from unconsolidated joint ventures	1,791	14,834
Interest and other income	1,505	1,407
Gains from investments in securities	259	393
Gains on sales of real estate	69,792	95,084
General and administrative expense	29,353	28,791
Transaction costs	25	327
Depreciation and amortization expense	157,461	152,224
Interest expense	105,309	108,757
Noncontrolling interest in property partnerships	10,464	15,208
Noncontrolling interest-redeemable preferred units	0	3
Preferred dividends / distributions	2,618	2,589
Net income attributable to the Company's common shareholders / unitholders	$ 207,296	$ 193,369

Subsequent Events subsequent Ev

Subsequent Events subsequent Events (Details) $ in Thousands	Apr. 11, 2016USD ($)ft²yr	Apr. 04, 2016USD ($)ft²yr	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Apr. 22, 2016USD ($)ft²	Dec. 31, 2015USD ($)
Subsequent Event [Line Items]
Mortgage loan			$ 3,416,622			$ 3,435,242
Repayments of Secured Debt			$ 6,265	$ 7,024
Secured Debt [Member] | Fountain Square [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Repayments of Secured Debt	$ 211,300
Coupon/Stated Rate	5.71%
Annapolis Junction Building One [Member] | Secured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage	50.00%
Mortgage loan	$ 40,000
Debt Instrument, Basis Spread on Variable Rate	1.75%
Number of extensions	1
Extension Option (in years) | yr	3
Net Rentable Area (in sf) | ft²	118,000
Peterson Way [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area (in sf) | ft²					218,000
Purchase price					$ 78,000
Portion of Building Leased (percentage)					100.00%
Peterson Way [Member] | Future development [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Net Rentable Area (in sf) | ft²					632,000
Construction Loans [Member] | Annapolis Junction Building Seven [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Ownership Percentage		50.00%
Construction Loan		$ 21,500
Construction Loan Facility Borrowing Capacity		$ 22,000
Debt Instrument, Basis Spread on Variable Rate		1.65%
Number of extensions		1
Extension Option (in years) | yr		1
Net Rentable Area (in sf) | ft²		127,000