Western Massachusetts Electric 10-Q 6 May 16 2016 Q1 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION	3 Months Ended
	Mar. 31, 2016USD ($)shares
Document And Entity [Line Items]
Entity Registrant Name	Eversource Energy
Document Period End Date	Mar. 31, 2016
Document Type	10-Q
Entity Central Index Key	72,741
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding | shares	317,207,036
Entity Public Float | $	$ 14,345,789,335
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Amendment Flag	false
trading	ES
The Connecticut Light And Power Company [Member]
Document And Entity [Line Items]
Entity Registrant Name	The Connecticut Light and Power Company
Entity Central Index Key	23,426
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Public Service Company Of New Hampshire [Member]
Document And Entity [Line Items]
Entity Registrant Name	Public Service Company of New Hampshire
Entity Central Index Key	315,256
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Western Massachusetts Electric Company [Member]
Document And Entity [Line Items]
Entity Registrant Name	Western Massachusetts Electric Company
Entity Central Index Key	106,170
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
NSTAR Electric Company [Member]
Document And Entity [Line Items]
Entity Registrant Name	NSTAR Electric Company
Entity Central Index Key	13,372
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current Assets:
Cash	$ 50,966	$ 23,947
Receivables, Net	890,977	775,480
Unbilled Revenues	192,084	202,647
Taxes Receivable	44,171	305,359
Fuel, Materials and Supplies	359,225	336,476
Regulatory Assets Current	919,311	845,843
Prepayments and Other Current Assets	133,813	129,034
Total Current Assets	2,590,547	2,618,786
Property, Plant and Equipment, Net	20,096,693	19,892,441
Deferred Debits and Other Assets:
Regulatory Assets Long Term	3,703,486	3,737,960
Goodwill	3,519,401	3,519,401
Marketable Securities	502,948	516,478
Other Long-Term Assets	299,400	295,243
Total Deferred Debits and Other Assets	8,025,235	8,069,082
Total Assets	30,712,475	30,580,309
Current Liabilities:
Notes Payable	769,500	1,160,953
Long-Term Debt - Current Portion	378,883	228,883
Accounts Payable - Current	646,440	813,646
Obligations to Third Party Suppliers	135,978	128,564
Renewable Portfolio Standards Compliance Obligation	170,021	130,354
Regulatory Liability Current	111,414	107,759
Other Liabilities - Current	381,678	419,631
Total Current Liabilities	2,593,914	2,989,790
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	5,284,255	5,147,678
Regulatory Liabilities Long-Term	526,452	513,595
Long-Term Derivative Liabilities	344,458	337,102
Accrued Pension, SERP and PBOP	1,355,422	1,407,288
Other Long-Term Liabilities	869,220	871,499
Total Deferred Credits and Other Liabilities	8,379,807	8,277,162
Capitalization:
Long-Term Debt	9,144,687	8,805,574
Noncontrolling Interest in Consolidated Subsidiary:
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	155,568	155,568
Common Shareholders' Equity:
Common Stock	1,669,392	1,669,313
Capital Surplus, Paid In	6,243,908	6,262,368
Retained Earnings	2,900,351	2,797,355
Accumulated Other Comprehensive Loss	(65,175)	(66,844)
Treasury Stock	(309,977)	(309,977)
Common Shareholders' Equity	10,438,499	10,352,215
Total Capitalization	19,738,754	19,313,357
Total Liabilities and Capitalization	30,712,475	30,580,309
The Connecticut Light And Power Company [Member]
Current Assets:
Cash	16,482	1,057
Receivables, Net	379,758	352,536
Accounts Receivable from Affiliated Companies	21,377	21,214
Unbilled Revenues	93,853	99,879
Taxes Receivable	4,650	137,643
Regulatory Assets Current	324,559	268,318
Materials and Supplies	48,083	43,124
Prepayments and Other Current Assets	49,753	32,234
Total Current Assets	938,515	956,005
Property, Plant and Equipment, Net	7,231,214	7,156,809
Deferred Debits and Other Assets:
Regulatory Assets Long Term	1,379,484	1,369,028
Other Long-Term Assets	113,017	111,115
Total Deferred Debits and Other Assets	1,492,501	1,480,143
Total Assets	9,662,230	9,592,957
Current Liabilities:
Notes Payable To Affiliated Companies	115,500	277,400
Long-Term Debt - Current Portion	150,000	0
Accounts Payable - Current	246,475	267,764
Accounts Payable to Affiliated Companies	59,275	66,456
Obligations to Third Party Suppliers	61,674	60,746
Regulatory Liability Current	62,999	61,155
Derivative Liabilities - Current	92,953	91,820
Other Liabilities - Current	118,697	110,631
Total Current Liabilities	907,573	935,972
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,881,725	1,820,865
Regulatory Liabilities Long-Term	77,744	74,830
Long-Term Derivative Liabilities	342,698	336,189
Accrued Pension, SERP and PBOP	267,706	271,056
Other Long-Term Liabilities	131,953	133,446
Total Deferred Credits and Other Liabilities	2,701,826	2,636,386
Capitalization:
Long-Term Debt	2,614,324	2,763,682
Noncontrolling Interest in Consolidated Subsidiary:
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	116,200	116,200
Common Shareholders' Equity:
Common Stock	60,352	60,352
Capital Surplus, Paid In	2,056,376	1,910,663
Retained Earnings	1,206,035	1,170,278
Accumulated Other Comprehensive Loss	(456)	(576)
Common Shareholders' Equity	3,322,307	3,140,717
Total Capitalization	6,052,831	6,020,599
Total Liabilities and Capitalization	9,662,230	9,592,957
NSTAR Electric Company [Member]
Current Assets:
Cash	3,504	3,346
Receivables, Net	256,760	229,936
Accounts Receivable from Affiliated Companies	2,990	4,034
Unbilled Revenues	28,596	29,464
Taxes Receivable	33,234	70,236
Fuel, Materials and Supplies	115,809	75,487
Regulatory Assets Current	361,307	348,408
Prepayments and Other Current Assets	13,957	11,448
Total Current Assets	816,157	772,359
Property, Plant and Equipment, Net	5,700,068	5,655,458
Deferred Debits and Other Assets:
Regulatory Assets Long Term	1,108,037	1,112,977
Other Long-Term Assets	58,323	62,467
Total Deferred Debits and Other Assets	1,166,360	1,175,444
Total Assets	7,682,585	7,603,261
Current Liabilities:
Notes Payable	148,500	62,500
Long-Term Debt - Current Portion	200,000	200,000
Accounts Payable - Current	189,594	228,250
Accounts Payable to Affiliated Companies	66,673	38,648
Obligations to Third Party Suppliers	62,588	56,718
Renewable Portfolio Standards Compliance Obligation	132,386	104,847
Regulatory Liability Current	4,997	3,281
Other Liabilities - Current	58,776	72,007
Total Current Liabilities	863,514	766,251
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,793,183	1,760,339
Regulatory Liabilities Long-Term	267,440	264,352
Accrued Pension, SERP and PBOP	188,974	209,153
Other Long-Term Liabilities	123,336	120,939
Total Deferred Credits and Other Liabilities	2,372,933	2,354,783
Capitalization:
Long-Term Debt	1,829,984	1,829,766
Noncontrolling Interest in Consolidated Subsidiary:
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	43,000	43,000
Common Shareholders' Equity:
Common Stock	0	0
Capital Surplus, Paid In	995,378	995,378
Retained Earnings	1,577,241	1,613,538
Accumulated Other Comprehensive Loss	535	545
Common Shareholders' Equity	2,573,154	2,609,461
Total Capitalization	4,446,138	4,482,227
Total Liabilities and Capitalization	7,682,585	7,603,261
Public Service Company Of New Hampshire [Member]
Current Assets:
Cash	3,580	1,733
Receivables, Net	89,138	77,546
Accounts Receivable from Affiliated Companies	7,667	2,352
Unbilled Revenues	36,497	38,207
Taxes Receivable	0	43,128
Fuel, Materials and Supplies	149,965	156,868
Regulatory Assets Current	101,633	104,971
Prepayments and Other Current Assets	5,963	24,302
Total Current Assets	394,443	449,107
Property, Plant and Equipment, Net	2,881,435	2,855,363
Deferred Debits and Other Assets:
Regulatory Assets Long Term	245,760	257,873
Other Long-Term Assets	34,703	34,176
Total Deferred Debits and Other Assets	280,463	292,049
Total Assets	3,556,341	3,596,519
Current Liabilities:
Notes Payable To Affiliated Companies	157,100	231,300
Accounts Payable - Current	64,717	87,925
Accounts Payable to Affiliated Companies	29,814	24,214
Regulatory Liability Current	4,723	6,898
Accrued Taxes	21,231	4,648
Other Liabilities - Current	43,132	39,273
Total Current Liabilities	320,717	394,258
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	723,110	705,894
Regulatory Liabilities Long-Term	47,930	47,851
Accrued Pension, SERP and PBOP	77,218	89,579
Other Long-Term Liabilities	50,453	50,746
Total Deferred Credits and Other Liabilities	898,711	894,070
Capitalization:
Long-Term Debt	1,071,275	1,071,017
Common Shareholders' Equity:
Common Stock	0	0
Capital Surplus, Paid In	760,134	748,634
Retained Earnings	511,559	494,901
Accumulated Other Comprehensive Loss	(6,055)	(6,361)
Common Shareholders' Equity	1,265,638	1,237,174
Total Capitalization	2,336,913	2,308,191
Total Liabilities and Capitalization	3,556,341	3,596,519
Western Massachusetts Electric Company [Member]
Current Assets:
Cash	2,269	834
Receivables, Net	59,324	50,912
Accounts Receivable from Affiliated Companies	8,612	18,633
Unbilled Revenues	13,753	15,065
Taxes Receivable	6,431	33,407
Regulatory Assets Current	61,363	56,166
Prepayments and Other Current Assets	8,396	7,882
Total Current Assets	160,148	182,899
Property, Plant and Equipment, Net	1,590,524	1,575,306
Deferred Debits and Other Assets:
Regulatory Assets Long Term	131,432	135,010
Other Long-Term Assets	26,148	24,875
Total Deferred Debits and Other Assets	157,580	159,885
Total Assets	1,908,252	1,918,090
Current Liabilities:
Notes Payable To Affiliated Companies	143,500	143,400
Accounts Payable - Current	34,240	58,364
Accounts Payable to Affiliated Companies	16,740	19,896
Renewable Portfolio Standards Compliance Obligation	11,899	6,395
Regulatory Liability Current	9,760	13,122
Other Liabilities - Current	18,404	23,532
Total Current Liabilities	234,543	264,709
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	480,250	470,539
Regulatory Liabilities Long-Term	13,775	11,597
Accrued Pension, SERP and PBOP	17,897	19,515
Other Long-Term Liabilities	39,566	36,819
Total Deferred Credits and Other Liabilities	551,488	538,470
Capitalization:
Long-Term Debt	517,200	517,329
Common Shareholders' Equity:
Common Stock	10,866	10,866
Capital Surplus, Paid In	391,398	391,398
Retained Earnings	205,467	198,140
Accumulated Other Comprehensive Loss	(2,710)	(2,822)
Common Shareholders' Equity	605,021	597,582
Total Capitalization	1,122,221	1,114,911
Total Liabilities and Capitalization	$ 1,908,252	$ 1,918,090

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Revenues	$ 2,055,635	$ 2,513,431
Operating Expenses:
Purchased Power and Transmission	754,859	1,162,049
Operations and Maintenance	320,136	333,382
Depreciation	173,986	163,837
Amortization of Regulatory Assets/(Liabilities), Net	20,997	60,604
Energy Efficiency Programs	137,175	146,603
Taxes Other Than Income Taxes	159,946	149,481
Total Operating Expenses	1,567,099	2,015,956
Operating Income	488,536	497,475
Interest Expense:
Total Interest Expense	98,212	94,843
Other Income [Abstract]
Other Income/(Loss), Net	2,011	5,727
Income Before Income Tax Expense	392,335	408,359
Income Tax Expense	146,302	153,226
Net Income	246,033	255,133
Net Income Attributable to Noncontrolling Interests	1,880	1,879
Net Income Attributable to Controlling Interests	$ 244,153	$ 253,254
Earnings Per Share Basic And Diluted	$ 0.77	$ 0.80
Common Stock Dividends Per Share Declared	$ 0.45	$ 0.42
Weighted Average Common Shares Outstanding:
Basic	317,517,141	317,090,841
Diluted	318,481,050	318,491,188
The Connecticut Light And Power Company [Member]
Operating Revenues	$ 735,317	$ 804,917
Operating Expenses:
Purchased Power and Transmission	272,600	333,619
Operations and Maintenance	110,843	117,357
Depreciation	56,969	52,902
Amortization of Regulatory Assets/(Liabilities), Net	9,878	48,306
Energy Efficiency Programs	38,090	42,807
Taxes Other Than Income Taxes	75,465	68,080
Total Operating Expenses	563,845	663,071
Operating Income	171,472	141,846
Interest Expense:
Total Interest Expense	36,498	36,624
Other Income [Abstract]
Other Income/(Loss), Net	936	2,159
Income Before Income Tax Expense	135,910	107,381
Income Tax Expense	48,863	38,147
Net Income	87,047	69,234
NSTAR Electric Company [Member]
Operating Revenues	614,216	766,808
Operating Expenses:
Purchased Power and Transmission	254,336	401,867
Operations and Maintenance	94,696	75,824
Depreciation	51,886	48,768
Amortization of Regulatory Assets/(Liabilities), Net	4,683	(5,565)
Energy Efficiency Programs	66,243	55,417
Taxes Other Than Income Taxes	32,555	30,962
Total Operating Expenses	504,399	607,273
Operating Income	109,817	159,535
Interest Expense:
Total Interest Expense	20,889	20,446
Other Income [Abstract]
Other Income/(Loss), Net	(334)	602
Income Before Income Tax Expense	88,594	139,691
Income Tax Expense	34,101	56,130
Net Income	54,493	83,561
Public Service Company Of New Hampshire [Member]
Operating Revenues	242,290	284,847
Operating Expenses:
Purchased Power and Transmission	50,214	99,579
Operations and Maintenance	59,213	58,428
Depreciation	28,235	25,646
Amortization of Regulatory Assets/(Liabilities), Net	8,518	15,132
Energy Efficiency Programs	3,620	3,772
Taxes Other Than Income Taxes	21,795	19,079
Total Operating Expenses	171,595	221,636
Operating Income	70,695	63,211
Interest Expense:
Total Interest Expense	12,461	11,272
Other Income [Abstract]
Other Income/(Loss), Net	150	382
Income Before Income Tax Expense	58,384	52,321
Income Tax Expense	22,326	20,276
Net Income	36,058	32,045
Western Massachusetts Electric Company [Member]
Operating Revenues	128,095	152,864
Operating Expenses:
Purchased Power and Transmission	39,563	69,661
Operations and Maintenance	21,805	19,784
Depreciation	11,371	10,375
Amortization of Regulatory Assets/(Liabilities), Net	1,212	3,927
Energy Efficiency Programs	10,856	11,075
Taxes Other Than Income Taxes	10,232	9,437
Total Operating Expenses	95,039	124,259
Operating Income	33,056	28,605
Interest Expense:
Total Interest Expense	6,004	6,823
Other Income [Abstract]
Other Income/(Loss), Net	(149)	575
Income Before Income Tax Expense	26,903	22,357
Income Tax Expense	10,076	9,113
Net Income	$ 16,827	$ 13,244

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net Income	$ 246,033	$ 255,133
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	534	509
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	264	132
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	871	954
Other Comprehensive Income (Loss), Net of Tax, Total	1,669	1,595
Comprehensive Income Attributable to Noncontrolling Interests	(1,880)	(1,879)
Comprehensive Income	245,822	254,849
The Connecticut Light And Power Company [Member]
Net Income	87,047	69,234
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	111	111
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	9	4
Other Comprehensive Income (Loss), Net of Tax, Total	120	115
Comprehensive Income	87,167	69,349
NSTAR Electric Company [Member]
Net Income	54,493	83,561
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(10)	(180)
Other Comprehensive Income (Loss), Net of Tax, Total	(10)	(180)
Comprehensive Income	54,483	83,381
Public Service Company Of New Hampshire [Member]
Net Income	36,058	32,045
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	290	291
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	16	8
Other Comprehensive Income (Loss), Net of Tax, Total	306	299
Comprehensive Income	36,364	32,344
Western Massachusetts Electric Company [Member]
Net Income	16,827	13,244
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	109	85
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	3	1
Other Comprehensive Income (Loss), Net of Tax, Total	112	86
Comprehensive Income	$ 16,939	$ 13,330

CONSOLIDATED STATEMENT OF CASH

CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Activities:
Net Income	$ 246,033	$ 255,133
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	173,986	163,837
Deferred Income Tax Expense (Benefit)	141,132	148,193
Pension, SERP and PBOP Expense	11,583	26,495
Pension and PBOP Contributions	(30,383)	(26,659)
Regulatory Over/(Under) Recoveries, Net	(82,772)	(110,748)
Amortization of Regulatory Assets/(Liabilities), Net	20,997	60,604
Other	(16,532)	(11,891)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(133,965)	(328,299)
Increase Decrease in Fuel, Materials and Supplies	(22,748)	68,172
Taxes Receivable/(Accrued)	279,106	272,021
Accounts Payable	(76,317)	(59,496)
Other Current Assets and Liabilities, Net	(10,156)	34,179
Net Cash Flows Provided by Operating Activities	499,964	491,541
Investing Activities:
Investments in Property, Plant and Equipment	(431,472)	(362,586)
Proceeds from Sales of Marketable Securities	136,805	114,730
Purchases of Marketable Securities	(135,427)	(116,735)
Other Investing Activities	5,494	66
Net Cash Flows Used in Investing Activities	(424,600)	(364,525)
Financing Activities:
Cash Dividends on Common Stock	(141,157)	(132,433)
Cash Dividends on Preferred Stock	(1,880)	(1,879)
Increase/(Decrease) in Short-Term Debt	(391,453)	(399,575)
Issuance of Long-Term Debt	500,000	450,000
Other Financing Activities	(13,855)	(10,805)
Net Cash Flows Provided by/(Used in) Financing Activities	(48,345)	(94,692)
Net Increase/(Decrease) in Cash	27,019	32,324
Cash - Beginning of Year	23,947	38,703
Cash - End of Year	50,966	71,027
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	87,047	69,234
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	56,969	52,902
Deferred Income Tax Expense (Benefit)	58,363	19,340
Regulatory Over/(Under) Recoveries, Net	(70,195)	(67,393)
Amortization of Regulatory Assets/(Liabilities), Net	9,878	48,306
Other	2,216	6,205
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(37,501)	(124,969)
Taxes Receivable/(Accrued)	141,951	158,163
Accounts Payable	(5,040)	(20,194)
Other Current Assets and Liabilities, Net	(22,533)	(7,727)
Net Cash Flows Provided by Operating Activities	221,155	133,867
Investing Activities:
Investments in Property, Plant and Equipment	(147,131)	(127,631)
Proceeds From Sale Of Property Plant And Equipment	9,047
Other Investing Activities	49	1,981
Net Cash Flows Used in Investing Activities	(138,035)	(125,650)
Financing Activities:
Cash Dividends on Common Stock	(49,900)	(49,000)
Cash Dividends on Preferred Stock	(1,390)	(1,390)
Increase/(Decrease) in Notes Payable to Affiliate	(161,900)	56,700
Capital Contributions from NU Parent	145,700	0
Other Financing Activities	(205)	(65)
Net Cash Flows Provided by/(Used in) Financing Activities	(67,695)	6,245
Net Increase/(Decrease) in Cash	15,425	14,462
Cash - Beginning of Year	1,057	2,356
Cash - End of Year	16,482	16,818
NSTAR Electric Company [Member]
Operating Activities:
Net Income	54,493	83,561
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	51,886	48,768
Deferred Income Tax Expense (Benefit)	32,878	41,297
Pension, SERP and PBOP Expense, Net of Contributions	(12,953)	1,164
Regulatory Over/(Under) Recoveries, Net	(16,746)	(103,142)
Amortization of Regulatory Assets/(Liabilities), Net	4,683	(5,565)
Bad Debt Expense	6,875	8,049
Other	(10,120)	(21,885)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(30,176)	(90,465)
Increase Decrease in Fuel, Materials and Supplies	(40,322)	(13,504)
Taxes Receivable/(Accrued)	33,938	96,319
Accounts Payable	(26,838)	29,210
Accounts Payable Related Parties	29,069	96,368
Other Current Assets and Liabilities, Net	19,600	51,157
Net Cash Flows Provided by Operating Activities	96,267	221,332
Investing Activities:
Investments in Property, Plant and Equipment	(91,319)	(79,776)
Other Investing Activities		53
Net Cash Flows Used in Investing Activities	(91,319)	(79,723)
Financing Activities:
Cash Dividends on Common Stock	(90,300)	(49,500)
Cash Dividends on Preferred Stock	(490)	(490)
Increase/(Decrease) in Short-Term Debt	86,000	(86,500)
Other Financing Activities	0	5
Net Cash Flows Provided by/(Used in) Financing Activities	(4,790)	(136,485)
Net Increase/(Decrease) in Cash	158	5,124
Cash - Beginning of Year	3,346	12,773
Cash - End of Year	3,504	17,897
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	36,058	32,045
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	28,235	25,646
Deferred Income Tax Expense (Benefit)	21,181	38,767
Regulatory Over/(Under) Recoveries, Net	(2,291)	(288)
Amortization of Regulatory Assets/(Liabilities), Net	8,518	15,132
Other	(9,166)	2,999
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(17,207)	(31,556)
Increase Decrease in Fuel, Materials and Supplies	6,903	34,572
Taxes Receivable/(Accrued)	57,935	(16,576)
Accounts Payable	2,100	(4,285)
Other Current Assets and Liabilities, Net	24,021	17,468
Net Cash Flows Provided by Operating Activities	156,287	113,924
Investing Activities:
Investments in Property, Plant and Equipment	(72,338)	(71,905)
Other Investing Activities	84	(2,277)
Net Cash Flows Used in Investing Activities	(72,254)	(74,182)
Financing Activities:
Cash Dividends on Common Stock	(19,400)	(26,500)
Increase/(Decrease) in Notes Payable to Affiliate	(74,200)	(8,500)
Capital Contributions from NU Parent	11,500
Other Financing Activities	(86)	(82)
Net Cash Flows Provided by/(Used in) Financing Activities	(82,186)	(35,082)
Net Increase/(Decrease) in Cash	1,847	4,660
Cash - Beginning of Year	1,733	489
Cash - End of Year	3,580	5,149
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	16,827	13,244
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	11,371	10,375
Deferred Income Tax Expense (Benefit)	9,921	12,759
Regulatory Over/(Under) Recoveries, Net	(6,100)	(14,442)
Amortization of Regulatory Assets/(Liabilities), Net	1,212	3,927
Other	(541)	(1,197)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	2,197	(26,298)
Taxes Receivable/(Accrued)	26,976	64
Accounts Payable	(11,011)	85
Other Current Assets and Liabilities, Net	(136)	65
Net Cash Flows Provided by Operating Activities	50,716	(1,418)
Investing Activities:
Investments in Property, Plant and Equipment	(39,891)	(35,899)
Proceeds from Sales of Marketable Securities	479	23,249
Purchases of Marketable Securities	(466)	(23,442)
Net Cash Flows Used in Investing Activities	(39,878)	(36,092)
Financing Activities:
Cash Dividends on Common Stock	(9,500)	(9,300)
Increase/(Decrease) in Notes Payable to Affiliate	100	49,100
Other Financing Activities	(3)	(245)
Net Cash Flows Provided by/(Used in) Financing Activities	(9,403)	39,555
Net Increase/(Decrease) in Cash	1,435	2,045
Cash - Beginning of Year	834	0
Cash - End of Year	$ 2,269	$ 2,045

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Significant Accounting Policies [Text Block]	EVERSOURCE ENERGY AND SUBSIDIARIES THE CONNECTICUT LIGHT AND POWER COMPANY NSTAR E LECTRIC COMPANY AND SUBSIDIARY PUBLIC SERVICE COMPANY O F NEW HAMPSHIRE AND SUBSIDIARY WESTERN MASSACHUSETTS ELECTRIC COMPANY COMBINED NOTES TO CONDENSED FINANCIAL STATEMENTS (Unaudited) Refer to the Glossary of Terms included in this combined Quarterly Report on Form 10- Q for abbreviations and acronyms used throughout the combined notes to the unaudited condensed financial statements. 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A . Basis of Presentation Eversource Energy is a public utility holding company primarily engaged , through its wholly owned regulated utility subsidiaries , in the energy delivery business. Eversource Energy 's wholly owned regulat ed utility subsidiaries consist of CL&P, NSTAR Electric, PSNH, WMECO, Yankee Gas and NSTAR Gas. Eversource provides energy deliv ery service to approximately 3.6 million electric and natural gas customers through these six regulated utilities in Connecticut, Ma ssachusetts and New Hampshire . The unaudited condensed consolidated financial stateme nts of Eversource , NSTAR Electric and PSNH include the accounts of each o f their respective subsidiaries. Intercompany transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements of Eversource , NSTAR Electric and PSNH and the unaudited condensed financial statements of CL&P and WMECO are herein collectively referred to as the "financial statements." The combined notes to the financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures included in annual financial statements prepared in accordance with GAAP have been omitted pursuant to such rules and regulations. The accompanying financial statements should be read in conjunction with the entirety of this combine d Quarterly Report on Form 10 -Q and the 201 5 combined Annual Report on Form 10 -K of Eversource , CL&P, NSTAR Electric, PS NH and WMECO, which w as filed with the SEC. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource 's, CL&P's, NSTAR Electric's, PSNH's and WMECO's financial position as of March 31, 2016 and December 31, 201 5 , and the results of operations , comprehensive income and cash flows for the three months ended March 31, 2016 and 201 5 . The results of operations , comprehensive income and cash flows for the three months ended March 31, 2016 and 201 5 are not necessarily indicative of the results expected for a full year. Eversource consolidates CYAPC and YAEC because CL&P's, NSTAR Electric's, PSNH's and WMECO's combined ownership interest in each of these entities is greater than 50 percent. Intercompany transactions between CL&P, NSTAR Electric, PSNH and WMECO and the CYAPC and YAEC companies have been eliminated in consolidation of the Eversource financial statements. Access Northeast is a natural gas pipeline and storage project (the "Project") being developed jointly by Eversource, Spectra Energy Corp and National Grid. Access Northeast will enhance the Algonquin and Maritimes & Northeast pipeline systems using existing routes. Eversource and Spectra Energy Corp each own a 40 percent interest in the Project, with the remaining 20 percent interest owned by National Grid. The total projected cost for both the pipeline and the LNG storage is expected to be approximately $3 billion, to be funded in proportion to ownership interest ( approximately $1.2 billion by Eversource), with anticipated in-service dates commencing in November 2018. Eversource's cumulative equity investment in the Project as of March 31, 2016 of $1 4.4 million is presented in Other Long-Term Assets. Eversource 's utility subsidiaries ' distribution (including generation ) and transmission businesses are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for entities with rate-regulated operations , which considers the effect of regulation on the d ifferences in the timing of the recognition of certain revenues and expenses from those of other businesses and industries. See Note 2, "Regulatory Accounting," for further information. Certain reclassifications of prior period data were made in the accompanying financial statements to conform to the current period presentation and as a result of the adoption of new accounting guidance . See Note 1B,"Summary of Significant Accounting Policies – Accounting Standards," for further information. B. Accounting Standards Accounting Standards Issued but not Yet Effective : In May 2014, the Financial Accounting Standards Board (FASB) issued an Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers , which amends existing revenue recognition guidance and is required to be applied retrospectively (either to each reporting period presented or cumulatively at the date of initial application). In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers – Deferral of the Effective Date , which defers the effective date of ASU 2014-09 to the first quarter of 2018, with 2017 application permitted. The guidance continues to be interpreted on an industry specific level. The Company is evaluating the requirements and potential impacts of ASU 2014-09 and will implement the standard in the first quarter of 2018. The ASU is not currently expected to have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Liabilities , which is required to be implemented in the first quarter of 2018. The Company is reviewing the requirements of the ASU. The ASU will remove the available-for-sale designation for equity securities, whereby changes in fair value are recorded in other comprehensive income in shareholders' equity, and will require changes in fair value of all equity securities to be recorded in earnings beginning on January 1, 2018, with the unrealized gain or loss on available-for-sale equity securities as of that date reclassified to retained earnings as a cumulative effect of adoption. The fair value of available-for-sale equity securities subject to this guidance as of March 31, 2016 was approximately $ 52 million. The remaining available-for-sale equity securities included in marketable securities on the balance sheet are held in nuclear decommissioning trusts and are subject to regulatory accounting treatment and will not be impacted by this guidance. Implementation of the ASU for other financial instruments is not expected to have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. In February 2016, the FASB issued ASU 2016-02, Leases , which changes existing lease accounting guidance and is required to be applied in the first quarter of 201 9, with earlier application permitted. The ASU is required to be implemented for leases beginning on the date of initial application. For prior periods presented, leases are required to be recognized and measured using a modified retrospective approach. The Company is reviewing the requirements of ASU 2016-02. Recently Adopted Accounting Standards : In February 2015, the FASB i ssued ASU 2015-02, Consolidation: Amendments to the Consolidation Analysis . As required, the Company implemented this guidance as of January 1, 2016, which had no effect on the financial position or r esults of operations of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. In April 2015, the FASB issued ASU 2015-05, Intangibles – Goodwill and Other – Internal-Use Software: Customer's Accounting for Fees Paid in a Cloud Computing Arrangement , effective for annual periods, including interim periods, beginning after December 15 , 2015. The ASU amends existing guidance on intangibles and internal-use software and may be applied prospectively or retrospectively. On January 1, 2016, Eversource adopted the new accounting guidance prospectively , which did not have an impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation: Improvements to Employee Share-Based Payment Accounting . The ASU is intended to simplify some aspects of the accounting for share-based payment transactions. The ASU is required to be implemented in the first quarter of 2017, with early adoption permitted. The Company implemented this guidance in the first quarter of 2016. Beginning in the first quarter of 2016, the excess tax benefit associated with the distribution of stock compensation awards, previously recognized in Capital Surplus, Paid In in Common Shareholders' Equity on the balance sheet , are recognized in income tax expense in the income statement. The implementation reduced income tax expense by $ 2.5 million for the three months ended March 31, 2016. Also, beginning in 2016 , in the statement of cash flows, the excess tax benefits are presented as an operating activity rather than a financing activity , and in both periods presented , cash paid to satisfy the statutory income tax withholding obligation previously reflected within operating activities in 2015 is now treated as a financing activity . The cash payments to satisfy this obligation for the three months ended March 31, 2016 and 2015 were $ 9.1 million and $ 9.7 million, respectively, and are included in Other Financing Activities on the statements of cash flows. C . Provision for Uncollectible Accounts Eversource, including CL&P, NSTAR Electric, PSNH and WMECO, presents its receivables at estimated net realizable value by maintaining a provision for uncollectible accounts. This provision is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. The estimate is based upon historical collection and write-off experience and management's assessment of collectability from customers. Management continuously assesses the collectability of receivables and adjusts collectability estimates based on actual experience. Receivable balances are written off against the provision for uncollectible accounts when the customer accounts are terminated and these balances are deemed to be uncollectible. The PURA allows CL&P and Yankee Gas to accelerate the recovery of accounts receivable balances attributable to qualified customers under financial or medical duress (uncollectible hardship accounts receivable) outstanding for greater than 180 days and 90 days, respectively . The DPU allows WMECO and NSTAR Gas to also recover in rates amounts associated with certain uncollectible hardship accounts receivable. Certain of NSTAR Electric 's uncollectible hardship accounts receivable are expected to be recovered in future rates, similar to WMECO and NSTAR Gas. These u ncollectible customer account balances, which are expected to be recovered in rates, are included in Regulatory Assets or Other Long-Term Assets on the balance sheets . The total provision for uncollectible accounts and for uncollectible hardship accounts , which is included in the total provision, are included in Re cei vables, Net on the balance sheets, and were as follows: Total Provision for Uncollectible Accounts Uncollectible Hardship (Millions of Dollars) As of March 31, 2016 As of December 31, 2015 As of March 31, 2016 As of December 31, 2015 Eversource $ 197.6 $ 190.7 $ 118.9 $ 118.5 CL&P 84.9 79.5 71.3 68.1 NSTAR Electric 51.5 52.6 22.7 25.3 PSNH 9.1 8.7 - - WMECO 13.6 14.0 7.1 7.4 D . Fair Value Measurements Fair value measurement guidance is applied to derivative contracts that are not elected or designated as "normal purchases or normal sales" (normal) and to the marketable securities held in trusts. Fair value measurement guidanc e is also applied to valuations of the investments used to calculate the funded statu s of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial ass ets such as goodwill and AROs, and the estimate d fair value of preferred stock and long-term debt. Fair Value Hierarchy: In measuring fair value, Eversource uses observabl e market data when available in order to minimize the use of unobservable inputs. Inputs used in fair value measurements are categorized into three fair value hierarchy levels for disclosure purposes. The entire fair value measurement is categorized based on the lowest level of input that is significant to the fair value measurement. Eversource evaluates the classification of assets and liabilities measured at fair value on a quarterly basis, and Eversource ' s policy is to recognize transfers between levels of the fair value hierarchy as of the end of the reporting period. The three levels of the fair value hierarchy are described below: Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 - Inputs are quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs are observable. Level 3 - Quoted market prices are not available. Fair value is derived from valuation techniques in which one or more significant inputs or assumptions are unobservable. Where possible, valuation techniques incorporate observable market inputs that can be validated to external sources such as industry exchanges, including prices of energy and energy-related products. Determination of Fair Value: The valuation techniques and inputs used in Eversource 's fair value measurements are described in Note 4 , "Derivative Instruments," Note 5 , "Marketable Securities," and Note 9 , "Fair Value of Financial Instruments," to the financial statements. E . Other Income, Net Items included within Other Income, Net on the statements of income primarily consist of investment income /( loss), interest income, AFUDC related to equity funds , and equity in earnings of equity method investees . Investment incom e /( loss) primarily relates to debt and equity securities held in trust . For further information, see Note 5, "Marketable Securities," to the financial statements. F . Other Taxes Gross receipts taxes levied by the state of Connecticut are collected by CL&P and Yankee Gas from their respective customers. These gross receipts taxes are shown separately with collections in Operating Revenues and with payments in Taxes Other Than I ncome Taxes on the statements of income as follows : For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 Eversource $ 42.2 $ 41.9 CL&P 36.0 33.0 As agents for state and local governments, Eversource' s companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income. G. Supplemental Cash Flow Information Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of March 31, 2016 As of March 31, 2015 Eversource $ 125.6 $ 110.4 CL&P 52.6 42.3 NSTAR Electric 11.7 21.9 PSNH 26.8 21.7 WMECO 10.7 8.3

REGULATORY ACCOUNTING

REGULATORY ACCOUNTING	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Public Utilities Disclosure [Text Block]	2 . REGULATORY ACCOUNTING Eversource's Regulated companies are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for rate-regulated operations, which considers the effect of regulation on the timing of the recognition of certain revenues and expenses. The Regulated companies' financial statements reflect the effects of the rate-making process. The rates charged to the customers of Eversource's Regulated companies are designed to collect each company's costs to provide service, including a return on investment. Management believes it is probable that each of the Regulated companies will recover their respective investments in long-lived assets, including regulatory assets. If management were to determine that it could no longer apply the accounting guidance applicable to rate-regulated enterprises to any of the Regulated companies' operations, or if management could not conclude it is probable that costs would be recovered from customers in future rates, the costs would be charged to net income in the period in which the determination is made. Regulatory Assets: The com ponents of regulatory assets were as follows: As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Benefit Costs $ 1,796.2 $ 1,828.2 Derivative Liabilities 389.6 388.0 Income Taxes, Net 646.6 650.9 Storm Restoration Costs 450.5 436.9 Goodwill-related 479.8 484.9 Regulatory Tracker Mechanisms 604.4 526.5 Contractual Obligations - Yankee Companies 130.4 134.4 Other Regulatory Assets 125.3 134.0 Total Regulatory Assets 4,622.8 4,583.8 Less: Current Portion 919.3 845.8 Total Long-Term Regulatory Assets $ 3,703.5 $ 3,738.0 As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Benefit Costs $ 406.3 $ 471.4 $ 161.5 $ 83.4 $ 413.6 $ 479.9 $ 164.2 $ 84.9 Derivative Liabilities 385.1 3.9 - - 380.8 1.3 - - Income Taxes, Net 444.3 85.7 29.9 31.3 444.4 85.7 34.5 31.8 Storm Restoration Costs 284.2 118.3 26.6 21.4 271.4 110.9 31.5 23.1 Goodwill-related - 411.9 - - - 416.3 - - Regulatory Tracker Mechanisms 104.3 325.9 98.1 45.3 45.1 311.0 101.2 40.1 Other Regulatory Assets 79.9 52.2 31.3 11.4 82.0 56.3 31.5 11.3 Total Regulatory Assets 1,704.1 1,469.3 347.4 192.8 1,637.3 1,461.4 362.9 191.2 Less: Current Portion 324.6 361.3 101.6 61.4 268.3 348.4 105.0 56.2 Total Long-Term Regulatory Assets $ 1,379.5 $ 1,108.0 $ 245.8 $ 131.4 $ 1,369.0 $ 1,113.0 $ 257.9 $ 135.0 Regulatory Costs in Other Long-Term Assets : T he Regulated companies had $ 76.1 million ( including $ 2.8 million for CL&P , $ 33 million for NSTAR Electric , $ 5.4 million for PSNH and $ 18 million for WMECO) and $ 75.3 million ( including $ 3.1 million for CL&P, $ 35.4 million for NSTAR Electric , $4.8 million for PSNH, and $ 16.7 million for WMECO) of additional regulatory costs as of March 31, 2016 and December 31, 201 5 , respectively, that were included in Other Long- Term Assets on the balance sheets. These amounts represent incurred costs for which recovery has not yet been specifically approved by the applicable regulatory agency. However, based on regulatory policies or past precedent on similar costs, m anagement believes it is probable that these costs will ultimately be approved and recovered from customers in rates . Regulatory Liabilities: The components of regulatory liabilities were as follows: As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Cost of Removal $ 444.7 $ 437.1 Regulatory Tracker Mechanisms 101.1 99.7 AFUDC - Transmission 65.9 66.1 Other Regulatory Liabilities 26.2 18.5 Total Regulatory Liabilities 637.9 621.4 Less: Current Portion 111.4 107.8 Total Long-Term Regulatory Liabilities $ 526.5 $ 513.6 As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Cost of Removal $ 26.7 $ 260.2 $ 47.3 $ 3.7 $ 24.1 $ 257.4 $ 47.2 $ 2.8 Regulatory Tracker Mechanisms 49.7 4.5 2.6 10.9 56.2 3.3 3.4 12.9 AFUDC - Transmission 51.2 5.8 - 8.9 51.5 5.7 - 8.9 Other Regulatory Liabilities 13.1 1.9 2.7 0.1 4.2 1.3 4.2 0.1 Total Regulatory Liabilities 140.7 272.4 52.6 23.6 136.0 267.7 54.8 24.7 Less: Current Portion 63.0 5.0 4.7 9.8 61.2 3.3 6.9 13.1 Total Long-Term Regulatory Liabilities $ 77.7 $ 267.4 $ 47.9 $ 13.8 $ 74.8 $ 264.4 $ 47.9 $ 11.6

PROPERTY, PLANT AND ACCUMULATED

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Property Plant And Equipment Disclosure [Text Block]	3. PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION The following tables summarize the investments in utility property, plant and equipment by asset category : As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Distribution - Electric $ 13,227.4 $ 13,054.8 Distribution - Natural Gas 2,759.1 2,727.2 Transmission - Electric 7,725.3 7,691.9 Generation 1,210.3 1,194.1 Electric and Natural Gas Utility 24,922.1 24,668.0 Other (1) 575.5 558.6 Property, Plant and Equipment, Gross 25,497.6 25,226.6 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,249.0) (6,141.1) Other (264.8) (255.6) Total Accumulated Depreciation (6,513.8) (6,396.7) Property, Plant and Equipment, Net 18,983.8 18,829.9 Construction Work in Progress 1,112.9 1,062.5 Total Property, Plant and Equipment, Net $ 20,096.7 $ 19,892.4 (1) These assets are primarily comprised of building improvements , computer software , hardware and equipment at Eversource S ervice . As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Distribution $ 5,429.5 $ 5,176.1 $ 1,839.5 $ 822.2 $ 5,377.2 $ 5,100.5 $ 1,804.8 $ 812.3 Transmission 3,631.3 2,137.7 936.1 971.0 3,618.0 2,131.3 928.2 964.9 Generation - - 1,174.3 36.0 - - 1,158.1 36.0 Property, Plant and Equipment, Gross 9,060.8 7,313.8 3,949.9 1,829.2 8,995.2 7,231.8 3,891.1 1,813.2 Less: Accumulated Depreciation (2,073.7) (1,924.4) (1,192.0) (317.0) (2,041.9) (1,886.8) (1,171.0) (307.0) Property, Plant and Equipment, Net 6,987.1 5,389.4 2,757.9 1,512.2 6,953.3 5,345.0 2,720.1 1,506.2 Construction Work in Progress 244.1 310.7 123.5 78.3 203.5 310.5 135.3 69.1 Total Property, Plant and Equipment, Net $ 7,231.2 $ 5,700.1 $ 2,881.4 $ 1,590.5 $ 7,156.8 $ 5,655.5 $ 2,855.4 $ 1,575.3 As of March 31, 2016 , PSNH had $ 1.2 billion in gross generation utility plant assets and related Accumulated Depreciation of $ 531.7 million. These generation assets are the subject of a divestiture agreement entered into on June 10 , 2015 between Eversource, PSNH and key New Hampshire officials whereby PSNH agreed to divest these generation assets upon NHPUC approval . Upon completion of the divestiture process , all remaining costs not recovered by the sale of these assets (stranded costs) will be recovered via bonds that will be secured by a non- bypassable charge or other recovery mechanisms in rates billed to PSNH's customers . See Note 8 E , " Commitments and Contingencies – PSNH Generation Restructuring, " for further information.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	4 . DERIVATIVE INSTRUMENTS The Regulated companies purchase and procure energy and energy-related products, which are subject to price volatility, for their customers. The costs associated with supplying energy to customers are recoverable from customers in future rates. The Regulated companies manage the risks associated with the price volatility of energy and energy-related products through the use of derivative and nonderivative contracts. Many of the derivative contracts meet the definition of, and are designated as, normal and qualify for accrual accounting under the applicable accounting guidance. The costs and benefits of derivative contracts that meet the definition of normal are recognized in Operating Expenses or Operating Revenues on the statements of income, as applicable, as electricity or natural gas is delivered. Derivative contracts that are not designated as normal are recorded at fair value as current or long-term Derivative Assets or Derivative Liabilities on the balance sheets. For the Regulated companies, regulatory assets or regulatory liabilities are recorded to offset the fair values of derivatives, as contract settlement amounts are recovered from, or refunded to, customers in their respective energy supply rates. The gross fair values of derivative assets and liabilities with the same counterparty are offset and reported as net Derivative Assets or Derivative Liabilities, with current and long-term portions, on the balance sheets. The following table presents the gross fair values of contracts, categorized by risk type, and the net amounts recorded as current or long-term derivative assets or liabilities : As of March 31, 2016 As of December 31, 2015 Commodity Supply Net Amount Commodity Supply Net Amount and Price Risk Recorded as and Price Risk Recorded as (Millions of Dollars) Management Netting (1) a Derivative Management Netting (1) a Derivative Current Derivative Assets: Level 3: Eversource $ 17.2 $ (11.0) $ 6.2 $ 16.7 $ (10.9) $ 5.8 CL&P 16.7 (11.0) 5.7 16.7 (10.9) 5.8 NSTAR Electric 0.5 - 0.5 - - - Long-Term Derivative Assets: Level 2: Eversource $ - $ - $ - $ 0.1 $ - $ 0.1 Level 3: Eversource 62.6 (16.9) 45.7 62.0 (19.3) 42.7 CL&P 61.8 (16.9) 44.9 60.7 (19.3) 41.4 NSTAR Electric 0.8 - 0.8 1.3 - 1.3 Current Derivative Liabilities: Level 2: Eversource $ (0.9) $ 0.2 $ (0.7) $ (5.8) $ - $ (5.8) Level 3: Eversource (95.1) - (95.1) (92.3) - (92.3) CL&P (93.0) - (93.0) (91.8) - (91.8) NSTAR Electric (2.1) - (2.1) (0.5) - (0.5) Long-Term Derivative Liabilities: Level 3: Eversource $ (344.5) $ - $ (344.5) $ (337.1) $ - $ (337.1) CL&P (342.7) - (342.7) (336.2) - (336.2) NSTAR Electric (1.8) - (1.8) (0.9) - (0.9) (1) Amounts represent derivativ e assets and liabilities that Eversource elected to record net on the balance sheets. These amounts are subject to master netting agreements or similar agreements for which the right of offset exists. For further information on the fair value of d erivative contracts, see Note 1 D , "Summary of Significant Accounting Policies - Fair Value Measurements ," to the financial statements. Deri vative Contract s at Fair Value with Offsetting Regulatory Amounts Commodity Supply and Price Risk Management : As required by regulation, CL&P, along with UI, has capacity-related contracts with generation facilities. CL&P has a sharing agreement with UI, with 80 percent of the costs or benefits of each contract borne by or allocated to CL&P and 20 percent borne by or allocated to UI. The combined capacity of these contracts is 787 MW. The capacity contracts extend through 2026 and obligate both CL&P and UI to make or receive payments on a monthly basis to or from the generation facilities based on the difference between a set capacity price and the capacity market price received in the ISO-NE capacity markets. In addition, CL&P has a contract to purchase 0.1 million MWh of energy per year through 2020. NSTAR Electric has a renewable energy contract to purchase 0.1 million MWh of energy per year through 2018 and a capacity-related contract to purchase up to 35 MW per year through 2019. As of March 31, 2016 and December 31, 2015, Eversource had NYMEX financial contracts for natural gas futures in order to reduce variability associated with the purchase price of approximately 5.3 million and 9.1 million MMBtu of natural gas, respectively. For the three months ended March 31, 2016 and 2015, there were losses of $ 30.5 million and $16.6 million, respectively, deferred as regulatory costs, which reflect the change in fair value associated with Eversource's derivative contracts. Credit Risk Certain of Eversource' s derivative contracts contain credit risk contingent provisions. These provisions require Eversource to maintain investment grade credit ratings from the major rating agencies and to post collateral for contracts in a net liability position over specified credit limits. As of March 31, 2016 and December 31, 2015, Eversource had $ 0.7 million and $ 5.8 million, respectively, of derivative contracts in a net liability position that were subject to credit risk contingent provisions and would have been required to post additional collateral of $ 0.9 million and $5.8 million, respectively, if certain of Eversource' s unsecured debt credit ratings had been downgraded to below investment grade. Fair Value Measurements of Derivative Instruments Derivative contracts classified as Level 2 in the fair value hierarchy relate to the financial contracts for natural gas futures. Prices are obtained from broker quotes and are based on actual market activity. The contracts are valued using NYMEX natural gas prices. Valuations of these contracts also incorporate discount rates using the yield curve approach. The fair value of derivative contracts classified as Level 3 utilizes significant unobservable inputs. The fair value is modeled using income techniques, such as discounted cash flow valuations adjusted for assumptions relating to exit price. Significant observable inputs for valuations of these contracts include energy and energy-related product prices in future years for which quoted prices in an active market exist. Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The future power and capacity prices for periods that are not quoted in an active market or established at auction are based on available market data and are escalated based on estimates of inflation in order to address the full time period of the contract. Valuations of derivative contracts using a discounted cash flow methodology include assumptions regarding the timing and likelihood of scheduled payments and also reflect non-performance risk, including credit, using the default probability approach based on the counterparty's credit rating for assets and the Company's credit rating for liabilities. Valuations incorporate estimates of premiums or discounts that would be required by a market participant to arrive at an exit price, using historical market transactions adjusted for the terms of the contract. The following is a summary of Eversource's , including CL&P's and NSTAR Electric's, Level 3 derivative contracts and the range of the significant unobservable inputs utilized in the valuations over the duration of the contracts: As of March 31, 2016 As of December 31, 2015 Range Period Covered Range Period Covered Capacity Prices: Eversource $ 11.08 - 15.82 per kW-Month 2017 - 2026 $ 10.81 - 15.82 per kW-Month 2016 - 2026 CL&P $ 11.08 - 12.60 per kW-Month 2020 - 2026 $ 10.81 - 12.60 per kW-Month 2019 - 2026 NSTAR Electric $ 12.11 - 15.82 per kW-Month 2017 - 2018 $ 10.81 - 15.82 per kW-Month 2016 - 2019 Forward Reserve: Eversource, CL&P $ 2.00 per kW-Month 2016 - 2024 $ 2.00 per kW-Month 2016 - 2024 REC Prices: Eversource, NSTAR Electric $ 30 - 35 per REC 2016 - 2018 $ 45 - 51 per REC 2016 - 2018 Exit price premiums of 5 percent through 22 percent are also applied on these contracts and reflect the uncertainty and illiquidity premiums that would be required based on the most recent market activity available for similar type contracts . Significant increases or decreases in future energy or capacity prices in isolation would decrease or increase, respectively, the fair value of the derivative l iability. Any increases in risk premiums would increase the fair value of the derivative li ability . Changes in these fair values are recorded as a regulat ory asset or liability and do not impact net income. Valuations using significant unobservable inputs: The following table present s changes in the Level 3 category of derivative assets and derivative liabilities measured at fair value on a recurring basis. The derivative assets and liabilities are presented on a net basis. For the Three Months Ended March 31, 2016 2015 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (380.9) $ (380.8) $ (0.1) $ (415.4) $ (410.9) $ (4.5) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (28.9) (24.6) (4.3) (12.1) (12.1) - Settlements 22.1 20.3 1.8 20.7 19.7 1.0 Fair Value as of End of Period $ (387.7) $ (385.1) $ (2.6) $ (406.8) $ (403.3) $ (3.5)

MARKETABLE SECURITIES

MARKETABLE SECURITIES	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Marketable Securities [Text Block]	5. MARKETABLE SECURITIES Eversource maintains trusts that hold marketable securities to fund certain non-qualified executive benefits. These trusts are not subject to regulatory oversight by state or federal agencies. CYAPC and YAEC maintain legally restricted trusts, each of which holds marketable securities, to fund the decommissioning and spent nuclear fuel removal obligations of their nuclear fuel storage facilities. Trading Securities: Eversource has elected to record certain equity securities a s trading securities, with the changes in fair values recorded in Other Income, Net on the statements of income. As of March 31, 2016 and December 31, 201 5 , these securities were classified as Leve l 1 in the fair value hierarchy and totaled $ 14.0 million and $ 14.2 million, respectively . For the three months ended March 31, 2016 and 2015, net gains on these securities of $0.2 million and $1.6 million, respectively , were recorded in Other Income, Net on the statements of income . Dividend income is recorded in Other Income, Net when dividends are declared. Available-for-Sale Securities: The following is a summary of available-for-sale securities , which are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of March 31, 2016 As of December 31, 2015 Pre-Tax Pre-Tax Pre-Tax Pre-Tax Eversource Amortized Unrealized Unrealized Amortized Unrealized Unrealized (Millions of Dollars) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Debt Securities $ 257.9 $ 7.0 $ (0.1) $ 264.8 $ 256.5 $ 4.5 $ (0.6) $ 260.4 Equity Securities 214.7 42.0 (3.5) 253.2 215.3 59.2 (3.4) 271.1 Eversource's debt and equity securities include CYAPC's and YAEC's marketable securities held in nuclear decommissioning trusts of $ 4 2 4.2 million and $ 436.9 million as of March 31, 2016 and December 31, 2015 , respectively. Unrealized gains and losses for the se nuclear decommissioning trusts are recorded in Marketable Securities with the corresponding offset to Other Long-Term Liabilities on the balance sheets, with no impact on the statements of income. Unrealized Losses and Other-than-Temporary Impairment: There have been no significant unrealized losses, other-than-temporary imp airments or credit losses for the three months ended March 31, 2016 and 2015 . Factors considered in determining whether a credit loss exists include the duration and severity of the impairment, adverse conditions specifically affecting the issuer, and the payment history, ratings and rating changes of the security. For asset-backed debt securities, underlying collateral and expected future cash flows are also evaluated. Realized Gains and Losses: Realized gains and losses on available-for-sale securities are reco rded in Other Income, Net for Eversource 's benefit trust and are offset in Other Long-Term Liabilities for CYAPC and YAEC. Eversource utilizes the specific ident ification basis method for the Eversource benefit trust , and the average cost basis method for the CYAPC and YAEC nuclear decommissioning trusts to compute the realized gains and losses on the sale of available-for-sale securities. Contractual Maturities : As of March 31 2016 , the contractual maturities of available-for-sale debt securities were as follows: Eversource Amortized (Millions of Dollars) Cost Fair Value Less than one year (1) $ 38.2 $ 38.2 One to five years 51.5 52.1 Six to ten years 42.7 44.4 Greater than ten years 125.5 130.1 Total Debt Securities $ 257.9 $ 264.8 1) Amou nts in the Less than one year category include securities in the CYAPC and YAEC nuclear decommissioning trusts, which are restricted and are classified in long-term Marketable Securities on the balance sheets. Fair Value Measurements: The following table presents the marketable securities recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Eversource (Millions of Dollars) As of March 31, 2016 As of December 31, 2015 Level 1: Mutual Funds and Equities $ 267.2 $ 285.3 Money Market Funds 32.1 26.9 Total Level 1 $ 299.3 $ 312.2 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 59.4 $ 46.6 Corporate Debt Securities 37.0 43.9 Asset-Backed Debt Securities 19.6 20.0 Municipal Bonds 108.0 111.4 Other Fixed Income Securities 8.7 11.6 Total Level 2 $ 232.7 $ 233.5 Total Marketable Securities $ 532.0 $ 545.7 U.S. government issued debt securities are valued using market approaches that incorporate transactions for the same or similar bonds and adjustments for yields and maturity dates. Corporate debt securities are valued using a market approach, utilizing recent trades of the same or similar instrument and also incorporating yield curves, credit spreads and specific bond terms and conditions. Asset-backed debt securities include collateralized mortgage obligations, commercial mortgage backed securities, and securities collateralized by auto loans, credit card loans or receivables. Asset-backed debt securities are valued using recent trades of similar instruments, prepayment assumptions, yield curves, issuance and maturity dates, and tranche information. Municipal bonds are valued using a market approach that incorporates reported trades and benchmark yields. Other fixed income securities are valued using pricing models, quoted prices of securities with similar characteristics, and discounted cash flows.

SHORT TERM DEBT

SHORT TERM DEBT	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Short Term Debt Text Block	6. SHORT-TERM AND LONG-TERM DEBT Commercial Paper Program s and Credit Agreements : Eversource parent has a $1.45 bil lion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. As of March 31, 2016 and December 31, 20 15, Eversource parent had $621 million and approximately $1.1 billion, respectively, in short-term borrowings outstanding under the Eversource parent commerci al paper program, leaving $829 million and $351.5 million of available borrowing capacity as of March 31, 2016 and December 31, 2015, respectively. The weighted-average interest rate on these borrowings as of March 31, 2016 and December 31, 2015 was 0.68 percent and 0.72 percent, respectively. As of March 31, 2016, there were intercompany loans from Eversource parent of $115.5 million to CL&P, $157.1 million to PSNH and $143.5 million to WMECO. As of December 31, 2015, there were intercompany loans from Eversource parent of $277.4 million to CL&P, $231.3 million to PSNH and $143.4 million to WMECO. Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas are parties to a five-year $1.45 billion revolving credit facility , which terminates on September 4, 2020. The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. NSTAR Electric has a $450 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. As of March 31, 2016 and December 31, 2015, NSTAR Electric had $148.5 million and $62.5 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $301.5 million and $387.5 million of available borrowing capacity as of March 31, 2016 and December 31, 2015, respectively. The weighted-average interest rate on these borrowings as of March 31, 2016 and December 31, 2015 was 0.38 percent and 0.40 percent, respectively. NSTAR Electric is a party to a five-year $450 mi llion revolving credit facility, which terminates on September 4, 2020. The revolving credit facility serves to backstop NSTAR Electric's $450 million commercial paper program . Except as described below, amounts outstanding under the commercial paper programs are included in Notes Payable for Eversource and NSTAR Electric and are classified in current liabilities on the balance sheets as all borrowings are outstanding for no more than 364 days at one time. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are included in Notes Payable to Eversource P arent and are classified in current liabilities on their respective balance sheets. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are eliminated in consolidation on Eversource's balance sheets. Long-Term Debt: In March 2016, Eversource parent issued $250 million of 2.5 0 percent Series I Senior Notes due to mature in 2021 and $250 million of 3.35 percent Series J Senior Notes due to mature in 2026. The proceed s , net of issuance costs, were used to repay short-term borrowings under the Eversource parent commercial paper program.

PENSION BENEFITS AND POSTRETIRE

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	7 . Pension Benefits and Postretirement Benefits Other than Pensions Eversource S ervice sponsors a defined benefit retirement plan (Pension Plan) that covers eligible employees, including , among others, employees of CL&P, NSTAR Electric, PSNH and WMECO . In addition to the Pension Plan, Eversource maintains non-qualified defined benefit retirement plans sponsored by Eversource Service (SERP Plans), which provide benefits in excess of Internal Revenue Code limitations to eligible participants consisting of current and retired employees . Eversource Se rvice also sponsors defined benefit postretirement plans that provide certain benefits, primarily medical, dental and life insurance, to retired employees that m et certain age and service eligibility requirements , including , among others, employees of CL&P, NSTAR Electric, PSNH and WMECO (PBOP Plan). Effective January 1, 2016, the Company refined its method of estimating the discount rate for the service and interest cost components of Pension and PBOP expense from the yield-curve approach to th e spot rate methodology, which provides a more precise measurement by matching projected cash flows to the corresponding spot rates on the yield curve. Historically, these components were estimated using the same weighted-average discount rate as for the funded status. The discount rates used to estimate the 2016 service cost were 4.89 percent and 5.14 percent for the Pension and PBOP plans, respectively. The discount rates used to estimate the 2016 interest cost were 3.80 percent and 3.72 percent for the Pension and PBOP plans, respectively. The total pre-tax benefit of this change on Pension and PBOP expense , prior to the capitalized portion and amounts deferred and recovered through rate reconciliation mechanisms, for the three months ended March 31, 2016 was approximately $12 million and $2.5 million for the Pension and PBOP plans, respectively. The components of net periodic benefit expense for the Pension, SERP and PBOP Plans are shown below. The net periodic benefit expense and the intercompany allocations less the capitalized portion of pension , SERP and PBOP amounts are included in Operations and Maintenance expense on the statements of income. Capitalized p ension and PBOP amounts relate to employees working on capital projects and are included in Property, Plant and Equipment, Net on the balance sheets . Pension, SERP and PBOP expense reflected in the statements of cash flows for CL&P, NSTAR Electric, PSNH and WMECO does not include the intercompany allocations or the corresponding capitalized portion, as these amounts are cash settled on a short-term basis. Pension and SERP Eversource For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 (1) Service Cost $ 19.4 $ 23.2 Interest Cost 46.5 56.6 Expected Return on Plan Assets (79.6) (84.3) Actuarial Loss 31.5 38.9 Prior Service Cost 0.9 0.9 Total Net Periodic Benefit Expense $ 18.7 $ 35.3 Capitalized Pension Expense $ 6.1 $ 9.6 PBOP Eversource For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 (1) Service Cost $ 3.1 $ 4.2 Interest Cost 9.7 11.9 Expected Return on Plan Assets (15.7) (16.8) Actuarial Loss 1.1 1.8 Prior Service Credit (0.1) (0.1) Total Net Periodic Benefit Expense/(Income) $ (1.9) $ 1.0 Capitalized PBOP Expense/(Income) $ (0.9) $ 0.2 Pension and SERP For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH (1) WMECO Service Cost $ 5.0 $ 3.4 $ 2.5 $ 0.9 $ 6.0 $ 3.8 $ 2.9 $ 1.1 Interest Cost 10.6 8.3 5.1 2.1 12.7 10.2 5.9 2.5 Expected Return on Plan Assets (18.2) (16.9) (9.7) (4.4) (19.7) (17.6) (10.0) (4.7) Actuarial Loss 6.7 8.4 2.5 1.4 8.2 9.6 3.0 1.6 Prior Service Cost 0.4 - 0.1 0.1 0.4 - 0.1 0.1 Total Net Periodic Benefit Expense $ 4.5 $ 3.2 $ 0.5 $ 0.1 $ 7.6 $ 6.0 $ 1.9 $ 0.6 Intercompany Allocations $ 3.3 $ 2.2 $ 1.0 $ 0.6 $ 6.4 $ 3.6 $ 1.7 $ 1.2 Capitalized Pension Expense $ 2.7 $ 1.8 $ 0.3 $ 0.2 $ 4.3 $ 2.8 $ 0.8 $ 0.5 PBOP For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH (1) WMECO Service Cost $ 0.5 $ 0.9 $ 0.3 $ 0.1 $ 0.6 $ 1.3 $ 0.4 $ 0.1 Interest Cost 1.4 4.0 0.8 0.3 1.8 4.8 1.0 0.4 Expected Return on Plan Assets (2.6) (6.4) (1.4) (0.6) (2.8) (6.8) (1.5) (0.6) Actuarial Loss 0.2 0.2 0.1 - 0.2 0.8 0.1 - Prior Service Credit - - - - - (0.1) - - Total Net Periodic Benefit Income $ (0.5) $ (1.3) $ (0.2) $ (0.2) $ (0.2) $ - $ - $ (0.1) Intercompany Allocations $ 0.2 $ 0.1 $ 0.0 $ 0.0 $ 0.5 $ 0.3 $ 0.1 $ 0.1 Capitalized PBOP Expense/(Income) $ (0.2) $ (0.6) $ 0.0 $ (0.1) $ 0.0 $ 0.1 $ - $ - (1) Amounts excluded approximately $1 million for the three months ended March 31, 2015 that represented amounts included in other deferred debits.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Commitments and Contingencies Disclosure [Text Block]	8 . COMMITMENTS AND CONTINGENCIES A. Environmental Matters E versource , CL&P, NSTAR Electric, PSNH and WMECO are subject to environmental laws and regulations intended to mitigate or remove the effect of past operations and improve or maintain the quality of the environment. These laws and regulations require the removal or the remedy of the effect on the environment of the disposal or release of certain specified hazardous substances at current and former operating sites. E versource , CL&P, NSTAR Electric , PSNH and WMECO have an active environmental auditing and training program and each believe s it is substantially in compliance with all enacted laws and regulations. The number of environmental sites and related reserves for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows : As of March 31, 2016 As of December 31, 2015 Reserve Reserve Number of Sites (in millions) Number of Sites (in millions) Eversource 64 $ 51.7 64 $ 51.1 CL&P 14 4.6 14 4.6 NSTAR Electric 15 2.3 15 2.4 PSNH 12 4.4 12 4.5 WMECO 4 0.6 4 0.6 Included in the Eversource number of sites and reserve amounts above are former MGP sites that were operated several decades ago and manufactured gas from coal and other processes, which resulted in certain by-products remaining in the environment that may pose a potential risk to human health and the environment , for which Eversource may have potential liability . The reserve balance s relat ed to these former MGP sites were $ 46.1 mi llion and $ 45.5 million as of March 31, 2016 and December 31, 201 5 , respectively, and related primarily to the natural gas business segment. These reserve estimates are subjective in nature as they take into consideration several different remediation options at each specific site. The reliability and precision of these estimates can be affected by several factors, including new information concerning either the level of contamination at the site, the extent of Eversource 's , CL&P 's , NSTAR Electric 's , PSNH 's , and WMECO's responsibility for remediation or the extent of remediation required, recently en acted laws and regulations or changes in cost estimates due to certain economic factors. It is possible that new information or future developments co u ld require a reassessment of the potential exposure to related environmental matters. As this information becomes available, management will continue to assess the potential exposure and adjust the reserves accordingly. B . Guarantees and Indemnifications In the normal course of business, Eversource parent provides credit assurances on behalf of its subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, in the form of guarantees. Eversource parent issued a declining balance guaranty on behalf of a wholly-owned subsidiary to guarantee the payment of the subsidiary's capital contributions for its investment in the Access Northeast project. The guarantee will n ot exceed $206 million and decrease s as capital contributions are made. The guaranty will expire upon the earlier of the full performance of the guaranteed obligations or December 31, 2021. Eversource parent issued a guaranty on behalf of its subsidiary, NPT, under which, beginning at the time the Northern Pass Transmission line goes into commercial operation, Eversource parent will guarantee the financial obligations of NPT under the TSA with HQ in an amount not to exceed $25 million. Eversource parent's obligations under the guaranty expire upon the full, final and indefeasible payment of the guaranteed obligations. Eversource parent has also guaranteed certain indemnification and other obligations as a result of the sale s of former unregulated subsidiar ies and the termination of an unregulated business , with maximum exposure s either not specified or not material. Management does not anticipate a material impact to Net Income as a result of these various guarantees and indemnifications. The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, an d guarantees to external parties, as of March 31, 2016: Maximum Exposure Company Description (in millions) Expiration Dates On behalf of subsidiaries: Eversource Gas Transmission LLC Access Northeast Project Capital Contributions Guarantee $ 187.9 2021 Various Surety Bonds (1) $ 38.7 2016 - 2018 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate $ 10.3 2019 and 2024 (1) Surety bo nd expiration dates reflect termination dates, the majority of which will be renewed or extended. C ertain surety bonds contain credit rating s triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource are downgraded . C. Spent Nuclear Fuel Litigation - Yankee Companies The Yankee Companies have filed separate complaints against the DOE in the Court of Federal Claims seeking monetary damages resulting from the DOE's failure to provide for a permanent facility to store spent nuclear fuel pursuant to the terms of the 1983 spent fuel and high level waste disposal contracts between t he Yankee Companies and the DOE. The court had previously awarded the Yankee Companies damages for Phase I and Phase II of litigation resulting from the DOE's failure to meet its contractual obligations. Phase I covered damages incurred in the years 1998 through 2002 and Phase II covered damages incurred in the years 2001 through 2008 for CYAPC and YAEC and from 2002 through 2008 for MYAPC. DOE Phase III Damages - In August 2013, the Yankee Companies each filed subsequent lawsuits against the DOE seeking recovery of actual damages incurred in the years 2009 through 2012. The DOE Phase III trial concluded on July 1, 2015, followed by a post-trial briefing that concluded on October 14, 2015. On March 25, 2016, the court issued its decision, awarding C YAPC, YAEC and MYAPC damages of $32.6 million, $19.6 million and $24.6 m illion, respectively . In total, the Yankee Companies were awarded $76.8 million of the $77.9 million in damages sought by the Yankee Companies in Phase III. Any amounts refunded to Eversource utilities , which include CL&P, N STAR Electric, PSNH and WMECO, will ultimately be refunded to utility customers. The parties have 60 days following the final judgment date to appeal. At this time, management cannot predict the timing or amount of damages that will ultimately be awarded. D . FERC ROE Complaints FERC ROE Complaints I, II and III : Three separate complaints have been filed at FERC by combinations of New England state attorneys general, state regulatory commissions, consumer advocates, consumer groups, municipal parties and other parties (the "Complainants"). In these three separate complaints, the Complainants challenged the NETOs' base ROE of 11.14 percent that had been utilized since 2006 and sought an order to reduce it prospectively from the date of the final FERC order and for the 15-month complaint refund periods stipulated in the separate complaints. In 2014, the FERC ordered a 10.57 percent base ROE for the first complaint refund period and prospectively from October 16, 2014, and that a utility's total or maximum ROE shall not exceed the top of the new zone of reasonableness, which was set at 11.74 percent. In late 2014, the NETOs made a compliance filing, and the Company began issuing refunds to customers from the first c omplaint period. The Company has refunded all amounts associated with the first complaint period. As a result of developments in this matter, the Company recorded reserves across the complaint periods at its electric subsidiaries in the first quarter of 2015 and recognized a pre-tax charge to earnings (excluding interest) of $ 20 million, of which $ 12.5 million was recorded at CL&P, $ 2.4 million at NSTAR Electric, $ 1 million at PSNH, and $ 4.1 million at WMECO. The pre-tax charge was recorded as a regulatory liability and as a reduction to Operating Revenues. The NETOs and Complainants have filed appeals for the first complaint to the D.C. Circuit Court of Appeals. A court decision is expected in late 2016. For the second and third complaints, the state parties, municipal utilities and FERC trial staff each believe that the base ROE should be reduced to an amount lower than 10.57 percent. The NETOs believe that the Complainants' positions are without merit. On March 22, 2016, the FERC ALJ issued an initial decision on the second and third FERC ROE complaints. For the second complaint period, the FERC ALJ recommended a zone of reasonableness of 7.12 percent to 10.42 percent and a base ROE of 9.59 percent. For the third complaint period, the FERC ALJ recommended a zone of reasonableness of 7.04 percent to 12.19 percent and a base ROE of 10.90 percent. The FERC ALJ also affirmed that the maximum ROE for transmission incentive projects should be the top of the zone of reasonableness. The NETOs filed briefs on April 21, 2016, in which the NETOs identified corrections and requested changes that should be made to the FERC ALJ's recommendations. A final FERC order is expected in late 2016 or early 2017. The Company believes that the range of potential loss for the second complaint period (the 15-month period beginning December 27, 2012) is from a base ROE of 10.57 percent to a base ROE of 9.59 percent. As the FERC ALJ initial decision on the third complaint recommended a base ROE of 10.90 percent, the Company concluded there is currently no range of potential loss for that complaint period. Given the differences between the recommended base ROEs in the FERC ALJ's initial decision on the second and third complaints, as well as other factors, the Company is unable to predict the outcome of the final FERC order on these complaints. The Company does not believe any base ROE outcome within the 10.57 percent to 9.59 percent range is more likely than the base ROEs used to record the current revenues and reserves, and therefore the Company believes that the current reserves for the second complaint period are appropriate at this time . The impact of a 10 basis point change to the existing base ROE of 10.57 percent would affect Eversource's after-tax earnings by approximately $3 million for each of the 15 -month second and third complaint periods. If the Company adjusted its reserves based on the recommendations in the FERC ALJ initial decision (for both the base ROE and maximum ROE for transmission incentive projects) for the second and third complaints, then it would result in an after-tax increase of approximately $34 million and an after-tax decrease of approximately $8 million, respectively, to the existing reserves. FERC ROE Complaint IV: On April 29, 2016, a fourth complaint was filed with the FERC. At this time, the Company is unable to predict the outcome of this complaint. E . PSNH Generation Restructuring On June 10, 2015, Eversource and PSNH entered into the 2015 Public Service Company of New Hampshire Restructuring and Rate Stabilization Agreement (the Agreement) with the New Hampshire Office of Energy and Planning, certain members of the NHPUC staff, the Office of Consumer Advocate, two State Senators, and several other parties. The Agreement was filed with the NHPUC on the same day. Under the t erms of the Agreement, PSNH agreed to divest its generation assets upon NHPUC approval. The Agreement is designed to provide a resolution of issues pertaining to PSNH's generation assets in pending regulatory proceedings before the NHPUC. The Agreement provided for the Clean Air Project prudence proceeding to be resolved and all remaining Clean Air Project costs to be included in rates effective January 1, 2016. As part of the Agreement, PSNH agreed to forego recovery of $25 million of the deferred equity return related to the Clean Air Project. In addition, PSNH will not seek a general distribution rate increase effective before July 1, 2017 and will contribute $5 million to create a clean energy fund, which will not be recoverable from its customers. In 2015, PSNH recorded the $5 million contribution as a long-term liability and an increase to Operations and Maintenance expense on the statements of income. Upon completion of the divestiture process, all remaining stranded costs will be recovered via bonds that will be secured by a non- bypassable charge or through other recoveries in rates billed to PSNH customers. On January 26, 2016, Advisory Staff of the NHPUC and the parties to the Agreement filed a stipulation with the NHPUC agreeing that near-term divestiture of PSNH's generation was in the public interest and that the Agreement should be approved. Implementation of the Agreement is subject to NHPUC appro val, which is expected in 2016. If the NHPUC approves the settlements and the sal e of the plants, the Company expects the plants will be sold in the first half of 2017. The sales price of the generating assets could be less than the carrying value, but the Company believe s that full recovery of PSNH's generation assets is probable through a combination of cash flows during the remaining operating period, sales proceeds upon divestiture, and recovery of stranded costs in future rates.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Fair Value Disclosures [Text Block]	9 . FAIR VALUE OF FINANCIAL INSTRUMENTS The following methods and assumptions were used to estimate the fair value of each of the following financial instruments: Preferred Stock and Long-Term Debt: The fair value of CL& P's and NSTAR Electric' s preferred stock is based upon pricing models that incorporate interest rates and other market factors, valuations or trades of similar securities and cash flow project ions. The fair value of long-term debt securities is based upon pricing models that incorporate quoted market prices for those issues or similar issues adjusted for market conditions, credit ratings of the respective companies and treasury benchmark yields. The fair values provided in the tables below are classified as Level 2 within the fair value hierarchy . Carrying amounts and estimated fair values are as follows : As of March 31, 2016 As of December 31, 2015 Eversource Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 155.8 $ 155.6 $ 157.9 Long-Term Debt 9,523.6 10,190.4 9,034.5 9,425.9 As of March 31, 2016 CL&P NSTAR Electric PSNH WMECO Carrying Fair Carrying Fair Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 113.7 $ 43.0 $ 42.1 $ - $ - $ - $ - Long-Term Debt 2,764.3 3,155.9 2,030.0 2,240.7 1,071.3 1,139.5 517.2 556.8 As of December 31, 2015 CL&P NSTAR Electric PSNH WMECO Carrying Fair Carrying Fair Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 114.9 $ 43.0 $ 43.0 $ - $ - $ - $ - Long-Term Debt 2,763.7 3,031.6 2,029.8 2,182.4 1,071.0 1,121.2 517.3 551.8 Derivative Instruments: Derivative instruments are carried at fair value. For further information, see Note 4, "Derivative Instruments," to the financial statements. Marketable Securities : Investments in marketable securities are carried at fair value. For further information, see Note 5, "Marketable Securities," to the financial statements. See Note 1D, "Summary of Significant Accounting Policies - Fair Value Measurements," for the fair value measurement policy and the fair value hierarchy .

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Comprehensive Income Note [Text Block]	10. ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) The change s in accumulated other comprehensive income /( loss) by component , net of tax, is as follows : For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 Qualified Unrealized Qualified Unrealized Cash Flow Gains/(Losses) Defined Cash Flow Gains on Defined Eversource Hedging on Marketable Benefit Hedging Marketable Benefit (Millions of Dollars) Instruments Securities Plans Total Instruments Securities Plans Total Balance as of Beginning of Period $ (10.3) $ (1.9) $ (54.6) $ (66.8) $ (12.4) $ 0.7 $ (62.3) $ (74.0) OCI Before Reclassifications - 0.2 - 0.2 - 0.1 - 0.1 Amounts Reclassified from AOCI 0.5 - 0.9 1.4 0.5 - 1.0 1.5 Net OCI 0.5 0.2 0.9 1.6 0.5 0.1 1.0 1.6 Balance as of End of Period $ (9.8) $ (1.7) $ (53.7) $ (65.2) $ (11.9) $ 0.8 $ (61.3) $ (72.4) E versource 's qualified cash flow hedging instruments represent interest rate swap agreements on debt issuances that were settled in prior years. The settlement amount was recorded in AOCI and is being amortized into Net Income over the term of the underlying debt instrument. CL&P, PSNH and WMECO continue to amortize interest rate swaps settled in prior years from AOCI into Interest Expense over the remaining life of the associated long-term debt. Such interest rate swaps are not material to their respective financial statements. The amortization expense of actuarial gains and losses on the defined benefit plans is amortized from AOCI into Operations and Maintenance expense over the average future employee service period, and is reflected in amounts reclassified from AOCI.

COMMON SHARES

COMMON SHARES	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule of Stock by Class [Text Block]	11 . COMMON SHARES The following table sets fo rth the E ve r s ource parent common shares and th e shares of common stock of CL&P, NSTAR Electric , PSNH and WMECO that were authorized and issued as well as the respective per share par values : Shares Authorized as of Per Share March 31, 2016 and Issued as of Par Value December 31, 2015 March 31, 2016 December 31, 2015 Eversource $ 5 380,000,000 333,878,402 333,862,615 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 100 100 PSNH $ 1 100,000,000 301 301 WMECO $ 25 1,072,471 434,653 434,653 As of both March 31, 2016 and December 31, 2015 , there were 16,671,366 E versour ce common shares held as treasury shares. As of March 31, 2016 and December 31, 2015 , Eversource common sha res outstanding were 317,207,036 and 317,191,249 , respectively .

COMMON SHARESHOLDERS' EQUITY AN

COMMON SHARESHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (NU)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	12 . COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS D ividends on the preferred stock of CL&P and NSTAR Electric totaled $1.9 million for the three months ended March 31, 2016 and 2015 . These dividends w ere presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. Noncontrolling Interest – Preferred Stock of Subsidiaries on the Eversource balance sheets totaled $155.6 million as of March 31, 2016 and December 31, 2015. Common Shareholders' Equity was fully attributable to the parent and Noncontrolling Interest – Preferred Stock of Subsidiaries was fully attributable to the noncontrolling interest on the Eversource balance sheets.

EARNINGS PER SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Earnings Per Share [Text Block]	13 . EARNINGS PER SHARE Basic EPS is computed based upon the weighted average number of common shares outstanding during each period. Diluted EPS is compu ted on the basis of the weighted average number of common shares outstanding plus the potential dilut ive effect of certain share-based compensation awards as if they were converted into common shares . The dilut ive effect of unvested RSU and performance share awards and unexercised stock options is calculated using the treasury stock method. RSU and performance share award s are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. For the three months ended March 31, 2016 and 2015, there were no antidilutive share awards excluded from the computation. The following table sets forth the components of basic and diluted EPS: Eversource For the Three Months Ended (Millions of Dollars, except share information) March 31, 2016 March 31, 2015 Net Income Attributable to Common Shareholders $ 244.2 $ 253.3 Weighted Average Common Shares Outstanding: Basic 317,517,141 317,090,841 Dilutive Effect 963,909 1,400,347 Diluted 318,481,050 318,491,188 Basic and Diluted EPS $ 0.77 $ 0.80

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Segment Reporting Disclosure [Text Block]	14 . SEGMENT INFORMATION Presentation: Eversource is organized into the Electric Distribution, Electric Transmission and Natural Gas Distribution reportable segments and Other based on a combination of factors, including the characteristics of each segments ' products and services, the sources of operating revenues and expenses and the regulatory environment i n which each segment operates. These reportable segments rep resent substantially all of Eversource 's total consolidated revenues. Revenues from the sale of electricity and natural gas primarily are derived from residential, commercial and industrial customers and are not dependent on any single customer. The Electric Distribution reportable segment includes the generation activities of PSNH and WMECO. The remainder of Eversource ' s operations is presented as Other in the tables below and primarily consists of 1) the equity in earnings of E versource parent from its subsidiaries and intercompany interest income, both of which are eliminated in consolidation, and interest e xpense related to the debt of Eversource parent, 2) the revenues and ex penses of Eversource Service , most of which are eliminated in consolidation, 3) the o perations of CYAPC and YAEC, 4 ) the results of Eversource Gas Transmission LLC and 5 ) the results of other un regulated subsidiaries, which are not part of its core business. Cash flows used for investments in plant included in the segment information below are cash capital expenditures that do not include amounts incurred but not paid, cost of removal, AFU DC related to equity funds, and the capitalized portions of pension e xpense. Eversource 's reportable segments are determined based upon the level at which Eversource 's chief operating decision maker assesses performance and makes decisions about the allocation o f company resources. Each of Eversource 's subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, has one reportable segment. Eversource 's operating segments and reporting units are consistent with its reportable business segments . Eversource 's segment information is as follows : For the Three Months Ended March 31, 2016 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,436.1 $ 342.6 $ 283.3 $ 214.2 $ (220.6) $ 2,055.6 Depreciation and Amortization (127.7) (15.8) (45.1) (6.9) 0.5 (195.0) Other Operating Expenses (1,088.9) (233.5) (73.0) (197.3) 220.6 (1,372.1) Operating Income 219.5 93.3 165.2 10.0 0.5 488.5 Interest Expense (48.0) (10.1) (28.0) (14.1) 2.0 (98.2) Other Income/(Loss), Net - (0.3) 2.6 305.5 (305.8) 2.0 Net Income Attributable to Common Shareholders $ 108.4 $ 50.9 $ 85.7 $ 302.5 $ (303.3) $ 244.2 Cash Flows Used for Investments in Plant $ 184.2 $ 52.1 $ 172.4 $ 22.8 $ - $ 431.5 For the Three Months Ended March 31, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,760.1 $ 507.4 $ 249.0 $ 240.0 $ (243.1) $ 2,513.4 Depreciation and Amortization (159.1) (18.2) (40.4) (7.2) 0.5 (224.4) Other Operating Expenses (1,342.8) (388.5) (74.1) (229.2) 243.1 (1,791.5) Operating Income 258.2 100.7 134.5 3.6 0.5 497.5 Interest Expense (47.6) (9.0) (27.6) (11.8) 1.2 (94.8) Other Income/(Loss), Net 2.2 (0.2) 2.9 314.9 (314.1) 5.7 Net Income Attributable to Common Shareholders $ 130.6 $ 55.6 $ 66.6 $ 312.9 $ (312.4) $ 253.3 Cash Flows Used for Investments in Plant $ 172.5 $ 30.0 $ 150.0 $ 10.1 $ - $ 362.6 The following table summarizes Eversource's segmented total assets: Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total As of March 31, 2016 $ 17,999.8 $ 3,134.1 $ 8,127.2 $ 13,335.6 $ (11,884.2) $ 30,712.5 As of December 31, 2015 17,981.3 3,104.5 8,019.3 13,256.7 (11,781.5) 30,580.3

SIGNIFCANT ACCOUNTING POLICIES

SIGNIFCANT ACCOUNTING POLICIES (Policies)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Notes To Consolidated Financial Statements [Abstract]
Organization Consolidation And Presentation Of Financial Statements Disclosure Text Block	A . Basis of Presentation Eversource Energy is a public utility holding company primarily engaged , through its wholly owned regulated utility subsidiaries , in the energy delivery business. Eversource Energy 's wholly owned regulat ed utility subsidiaries consist of CL&P, NSTAR Electric, PSNH, WMECO, Yankee Gas and NSTAR Gas. Eversource provides energy deliv ery service to approximately 3.6 million electric and natural gas customers through these six regulated utilities in Connecticut, Ma ssachusetts and New Hampshire . The unaudited condensed consolidated financial stateme nts of Eversource , NSTAR Electric and PSNH include the accounts of each o f their respective subsidiaries. Intercompany transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements of Eversource , NSTAR Electric and PSNH and the unaudited condensed financial statements of CL&P and WMECO are herein collectively referred to as the "financial statements." The combined notes to the financial statements have been prepared pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures included in annual financial statements prepared in accordance with GAAP have been omitted pursuant to such rules and regulations. The accompanying financial statements should be read in conjunction with the entirety of this combine d Quarterly Report on Form 10 -Q and the 201 5 combined Annual Report on Form 10 -K of Eversource , CL&P, NSTAR Electric, PS NH and WMECO, which w as filed with the SEC. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource 's, CL&P's, NSTAR Electric's, PSNH's and WMECO's financial position as of March 31, 2016 and December 31, 201 5 , and the results of operations , comprehensive income and cash flows for the three months ended March 31, 2016 and 201 5 . The results of operations , comprehensive income and cash flows for the three months ended March 31, 2016 and 201 5 are not necessarily indicative of the results expected for a full year. Eversource consolidates CYAPC and YAEC because CL&P's, NSTAR Electric's, PSNH's and WMECO's combined ownership interest in each of these entities is greater than 50 percent. Intercompany transactions between CL&P, NSTAR Electric, PSNH and WMECO and the CYAPC and YAEC companies have been eliminated in consolidation of the Eversource financial statements. Access Northeast is a natural gas pipeline and storage project (the "Project") being developed jointly by Eversource, Spectra Energy Corp and National Grid. Access Northeast will enhance the Algonquin and Maritimes & Northeast pipeline systems using existing routes. Eversource and Spectra Energy Corp each own a 40 percent interest in the Project, with the remaining 20 percent interest owned by National Grid. The total projected cost for both the pipeline and the LNG storage is expected to be approximately $3 billion, to be funded in proportion to ownership interest ( approximately $1.2 billion by Eversource), with anticipated in-service dates commencing in November 2018. Eversource's cumulative equity investment in the Project as of March 31, 2016 of $1 4.4 million is presented in Other Long-Term Assets. Eversource 's utility subsidiaries ' distribution (including generation ) and transmission businesses are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for entities with rate-regulated operations , which considers the effect of regulation on the d ifferences in the timing of the recognition of certain revenues and expenses from those of other businesses and industries. See Note 2, "Regulatory Accounting," for further information. Certain reclassifications of prior period data were made in the accompanying financial statements to conform to the current period presentation and as a result of the adoption of new accounting guidance . See Note 1B,"Summary of Significant Accounting Policies – Accounting Standards," for further information.
Receivables Policy Text Block	Eversource, including CL&P, NSTAR Electric, PSNH and WMECO, presents its receivables at estimated net realizable value by maintaining a provision for uncollectible accounts. This provision is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. The estimate is based upon historical collection and write-off experience and management's assessment of collectability from customers. Management continuously assesses the collectability of receivables and adjusts collectability estimates based on actual experience. Receivable balances are written off against the provision for uncollectible accounts when the customer accounts are terminated and these balances are deemed to be uncollectible.
Fair Value Of Financial Instruments Policy	Fair value measurement guidance is applied to derivative contracts that are not elected or designated as "normal purchases or normal sales" (normal) and to the marketable securities held in trusts. Fair value measurement guidanc e is also applied to valuations of the investments used to calculate the funded statu s of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial ass ets such as goodwill and AROs, and the estimate d fair value of preferred stock and long-term debt. Fair Value Hierarchy: In measuring fair value, Eversource uses observabl e market data when available in order to minimize the use of unobservable inputs. Inputs used in fair value measurements are categorized into three fair value hierarchy levels for disclosure purposes. The entire fair value measurement is categorized based on the lowest level of input that is significant to the fair value measurement. Eversource evaluates the classification of assets and liabilities measured at fair value on a quarterly basis, and Eversource ' s policy is to recognize transfers between levels of the fair value hierarchy as of the end of the reporting period. The three levels of the fair value hierarchy are described below: Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 - Inputs are quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-derived valuations in which all significant inputs are observable. Level 3 - Quoted market prices are not available. Fair value is derived from valuation techniques in which one or more significant inputs or assumptions are unobservable. Where possible, valuation techniques incorporate observable market inputs that can be validated to external sources such as industry exchanges, including prices of energy and energy-related products. Derivative contracts classified as Level 2 in the fair value hierarchy relate to the financial contracts for natural gas futures. Prices are obtained from broker quotes and are based on actual market activity. The contracts are valued using NYMEX natural gas prices. Valuations of these contracts also incorporate discount rates using the yield curve approach. The fair value of derivative contracts classified as Level 3 utilizes significant unobservable inputs. The fair value is modeled using income techniques, such as discounted cash flow valuations adjusted for assumptions relating to exit price. Significant observable inputs for valuations of these contracts include energy and energy-related product prices in future years for which quoted prices in an active market exist. Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The future power and capacity prices for periods that are not quoted in an active market or established at auction are based on available market data and are escalated based on estimates of inflation in order to address the full time period of the contract. Valuations of derivative contracts using a discounted cash flow methodology include assumptions regarding the timing and likelihood of scheduled payments and also reflect non-performance risk, including credit, using the default probability approach based on the counterparty's credit rating for assets and the Company's credit rating for liabilities. Valuations incorporate estimates of premiums or discounts that would be required by a market participant to arrive at an exit price, using historical market transactions adjusted for the terms of the contract. U.S. government issued debt securities are valued using market approaches that incorporate transactions for the same or similar bonds and adjustments for yields and maturity dates. Corporate debt securities are valued using a market approach, utilizing recent trades of the same or similar instrument and also incorporating yield curves, credit spreads and specific bond terms and conditions. Asset-backed debt securities include collateralized mortgage obligations, commercial mortgage backed securities, and securities collateralized by auto loans, credit card loans or receivables. Asset-backed debt securities are valued using recent trades of similar instruments, prepayment assumptions, yield curves, issuance and maturity dates, and tranche information. Municipal bonds are valued using a market approach that incorporates reported trades and benchmark yields. Other fixed income securities are valued using pricing models, quoted prices of securities with similar characteristics, and discounted cash flows. The following methods and assumptions were used to estimate the fair value of each of the following financial instruments: Preferred Stock and Long-Term Debt: The fair value of CL& P's and NSTAR Electric' s preferred stock is based upon pricing models that incorporate interest rates and other market factors, valuations or trades of similar securities and cash flow project ions. The fair value of long-term debt securities is based upon pricing models that incorporate quoted market prices for those issues or similar issues adjusted for market conditions, credit ratings of the respective companies and treasury benchmark yields. The fair values provided in the tables below are classified as Level 2 within the fair value hierarchy .
Other Taxes Policy	Gross receipts taxes levied by the state of Connecticut are collected by CL&P and Yankee Gas from their respective customers. These gross receipts taxes are shown separately with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the statements of income As agents for state and local governments, Eversource's companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income.
Public Utilities Policy Text Block	Eversource's Regulated companies are subject to rate-regulation that is based on cost recovery and meets the criteria for application of accounting guidance for rate-regulated operations, which considers the effect of regulation on the timing of the recognition of certain revenues and expenses. The Regulated companies' financial statements reflect the effects of the rate-making process. The rates charged to the customers of Eversource's Regulated companies are designed to collect each company's costs to provide service, including a return on investment. Management believes it is probable that each of the Regulated companies will recover their respective investments in long-lived assets, including regulatory assets. If management were to determine that it could no longer apply the accounting guidance applicable to rate-regulated enterprises to any of the Regulated companies' operations, or if management could not conclude it is probable that costs would be recovered from customers in future rates, the costs would be charged to net income in the period in which the determination is made.
Marketable Securities Policy	Unrealized Losses and Other-than-Temporary Impairment: There have been no significant unrealized losses, other-than-temporary imp airments or credit losses for the three months ended March 31, 2016 and 2015 . Factors considered in determining whether a credit loss exists include the duration and severity of the impairment, adverse conditions specifically affecting the issuer, and the payment history, ratings and rating changes of the security. For asset-backed debt securities, underlying collateral and expected future cash flows are also evaluated. Realized Gains and Losses: Realized gains and losses on available-for-sale securities are reco rded in Other Income, Net for Eversource 's benefit trust and are offset in Other Long-Term Liabilities for CYAPC and YAEC. Eversource utilizes the specific ident ification basis method for the Eversource benefit trust , and the average cost basis method for the CYAPC and YAEC nuclear decommissioning trusts to compute the realized gains and losses on the sale of available-for-sale securities.	. Dividend income is recorded in Other Income, Net when dividends are declared.
Environmental Costs Policy	Environmental Matters E versource , CL&P, NSTAR Electric, PSNH and WMECO are subject to environmental laws and regulations intended to mitigate or remove the effect of past operations and improve or maintain the quality of the environment. These laws and regulations require the removal or the remedy of the effect on the environment of the disposal or release of certain specified hazardous substances at current and former operating sites. E versource , CL&P, NSTAR Electric , PSNH and WMECO have an active environmental auditing and training program and each believe s it is substantially in compliance with all enacted laws and regulations.
Earnings Per Share Policy Text Block	Basic EPS is computed based upon the weighted average number of common shares outstanding during each period. Diluted EPS is compu ted on the basis of the weighted average number of common shares outstanding plus the potential dilut ive effect of certain share-based compensation awards as if they were converted into common shares . The dilut ive effect of unvested RSU and performance share awards and unexercised stock options is calculated using the treasury stock method. RSU and performance share award s are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied.
Segment Reporting Policy Policy Text Block	SEGMENT INFORMATION Presentation: Eversource is organized into the Electric Distribution, Electric Transmission and Natural Gas Distribution reportable segments and Other based on a combination of factors, including the characteristics of each segments ' products and services, the sources of operating revenues and expenses and the regulatory environment i n which each segment operates. These reportable segments rep resent substantially all of Eversource 's total consolidated revenues. Revenues from the sale of electricity and natural gas primarily are derived from residential, commercial and industrial customers and are not dependent on any single customer. The Electric Distribution reportable segment includes the generation activities of PSNH and WMECO. The remainder of Eversource ' s operations is presented as Other in the tables below and primarily consists of 1) the equity in earnings of E versource parent from its subsidiaries and intercompany interest income, both of which are eliminated in consolidation, and interest e xpense related to the debt of Eversource parent, 2) the revenues and ex penses of Eversource Service , most of which are eliminated in consolidation, 3) the o perations of CYAPC and YAEC, 4 ) the results of Eversource Gas Transmission LLC and 5 ) the results of other un regulated subsidiaries, which are not part of its core business. Cash flows used for investments in plant included in the segment information below are cash capital expenditures that do not include amounts incurred but not paid, cost of removal, AFU DC related to equity funds, and the capitalized portions of pension e xpense.

Provision for Uncollectible Acc

Provision for Uncollectible Accounts (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Accounts Notes Loans And Financing Receivable Text Block	Total Provision for Uncollectible Accounts Uncollectible Hardship (Millions of Dollars) As of March 31, 2016 As of December 31, 2015 As of March 31, 2016 As of December 31, 2015 Eversource $ 197.6 $ 190.7 $ 118.9 $ 118.5 CL&P 84.9 79.5 71.3 68.1 NSTAR Electric 51.5 52.6 22.7 25.3 PSNH 9.1 8.7 - - WMECO 13.6 14.0 7.1 7.4

Other Taxes (Tables)

Other Taxes (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
State Of Connecticut Gross Earnings Taxes [Table Text Block]	For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 Eversource $ 42.2 $ 41.9 CL&P 36.0 33.0

Supplemental Cash Flow Informat

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	G. Supplemental Cash Flow Information Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of March 31, 2016 As of March 31, 2015 Eversource $ 125.6 $ 110.4 CL&P 52.6 42.3 NSTAR Electric 11.7 21.9 PSNH 26.8 21.7 WMECO 10.7 8.3

REGULATORY ACCOUNTING (Tables)

REGULATORY ACCOUNTING (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Regulatory Assets Text Block	As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Benefit Costs $ 1,796.2 $ 1,828.2 Derivative Liabilities 389.6 388.0 Income Taxes, Net 646.6 650.9 Storm Restoration Costs 450.5 436.9 Goodwill-related 479.8 484.9 Regulatory Tracker Mechanisms 604.4 526.5 Contractual Obligations - Yankee Companies 130.4 134.4 Other Regulatory Assets 125.3 134.0 Total Regulatory Assets 4,622.8 4,583.8 Less: Current Portion 919.3 845.8 Total Long-Term Regulatory Assets $ 3,703.5 $ 3,738.0 As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Benefit Costs $ 406.3 $ 471.4 $ 161.5 $ 83.4 $ 413.6 $ 479.9 $ 164.2 $ 84.9 Derivative Liabilities 385.1 3.9 - - 380.8 1.3 - - Income Taxes, Net 444.3 85.7 29.9 31.3 444.4 85.7 34.5 31.8 Storm Restoration Costs 284.2 118.3 26.6 21.4 271.4 110.9 31.5 23.1 Goodwill-related - 411.9 - - - 416.3 - - Regulatory Tracker Mechanisms 104.3 325.9 98.1 45.3 45.1 311.0 101.2 40.1 Other Regulatory Assets 79.9 52.2 31.3 11.4 82.0 56.3 31.5 11.3 Total Regulatory Assets 1,704.1 1,469.3 347.4 192.8 1,637.3 1,461.4 362.9 191.2 Less: Current Portion 324.6 361.3 101.6 61.4 268.3 348.4 105.0 56.2 Total Long-Term Regulatory Assets $ 1,379.5 $ 1,108.0 $ 245.8 $ 131.4 $ 1,369.0 $ 1,113.0 $ 257.9 $ 135.0
Schedule Of Regulatory Liabilities Text Block	As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Cost of Removal $ 444.7 $ 437.1 Regulatory Tracker Mechanisms 101.1 99.7 AFUDC - Transmission 65.9 66.1 Other Regulatory Liabilities 26.2 18.5 Total Regulatory Liabilities 637.9 621.4 Less: Current Portion 111.4 107.8 Total Long-Term Regulatory Liabilities $ 526.5 $ 513.6 As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Cost of Removal $ 26.7 $ 260.2 $ 47.3 $ 3.7 $ 24.1 $ 257.4 $ 47.2 $ 2.8 Regulatory Tracker Mechanisms 49.7 4.5 2.6 10.9 56.2 3.3 3.4 12.9 AFUDC - Transmission 51.2 5.8 - 8.9 51.5 5.7 - 8.9 Other Regulatory Liabilities 13.1 1.9 2.7 0.1 4.2 1.3 4.2 0.1 Total Regulatory Liabilities 140.7 272.4 52.6 23.6 136.0 267.7 54.8 24.7 Less: Current Portion 63.0 5.0 4.7 9.8 61.2 3.3 6.9 13.1 Total Long-Term Regulatory Liabilities $ 77.7 $ 267.4 $ 47.9 $ 13.8 $ 74.8 $ 264.4 $ 47.9 $ 11.6

PROPERTY, PLANT AND ACCUMULAT25

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule of Public Utility Property, Plant, and Equipment [Text Block]	As of March 31, 2016 As of December 31, 2015 (Millions of Dollars) Eversource Eversource Distribution - Electric $ 13,227.4 $ 13,054.8 Distribution - Natural Gas 2,759.1 2,727.2 Transmission - Electric 7,725.3 7,691.9 Generation 1,210.3 1,194.1 Electric and Natural Gas Utility 24,922.1 24,668.0 Other (1) 575.5 558.6 Property, Plant and Equipment, Gross 25,497.6 25,226.6 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,249.0) (6,141.1) Other (264.8) (255.6) Total Accumulated Depreciation (6,513.8) (6,396.7) Property, Plant and Equipment, Net 18,983.8 18,829.9 Construction Work in Progress 1,112.9 1,062.5 Total Property, Plant and Equipment, Net $ 20,096.7 $ 19,892.4 As of March 31, 2016 As of December 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Distribution $ 5,429.5 $ 5,176.1 $ 1,839.5 $ 822.2 $ 5,377.2 $ 5,100.5 $ 1,804.8 $ 812.3 Transmission 3,631.3 2,137.7 936.1 971.0 3,618.0 2,131.3 928.2 964.9 Generation - - 1,174.3 36.0 - - 1,158.1 36.0 Property, Plant and Equipment, Gross 9,060.8 7,313.8 3,949.9 1,829.2 8,995.2 7,231.8 3,891.1 1,813.2 Less: Accumulated Depreciation (2,073.7) (1,924.4) (1,192.0) (317.0) (2,041.9) (1,886.8) (1,171.0) (307.0) Property, Plant and Equipment, Net 6,987.1 5,389.4 2,757.9 1,512.2 6,953.3 5,345.0 2,720.1 1,506.2 Construction Work in Progress 244.1 310.7 123.5 78.3 203.5 310.5 135.3 69.1 Total Property, Plant and Equipment, Net $ 7,231.2 $ 5,700.1 $ 2,881.4 $ 1,590.5 $ 7,156.8 $ 5,655.5 $ 2,855.4 $ 1,575.3

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value Text Block	As of March 31, 2016 As of December 31, 2015 Commodity Supply Net Amount Commodity Supply Net Amount and Price Risk Recorded as and Price Risk Recorded as (Millions of Dollars) Management Netting (1) a Derivative Management Netting (1) a Derivative Current Derivative Assets: Level 3: Eversource $ 17.2 $ (11.0) $ 6.2 $ 16.7 $ (10.9) $ 5.8 CL&P 16.7 (11.0) 5.7 16.7 (10.9) 5.8 NSTAR Electric 0.5 - 0.5 - - - Long-Term Derivative Assets: Level 2: Eversource $ - $ - $ - $ 0.1 $ - $ 0.1 Level 3: Eversource 62.6 (16.9) 45.7 62.0 (19.3) 42.7 CL&P 61.8 (16.9) 44.9 60.7 (19.3) 41.4 NSTAR Electric 0.8 - 0.8 1.3 - 1.3 Current Derivative Liabilities: Level 2: Eversource $ (0.9) $ 0.2 $ (0.7) $ (5.8) $ - $ (5.8) Level 3: Eversource (95.1) - (95.1) (92.3) - (92.3) CL&P (93.0) - (93.0) (91.8) - (91.8) NSTAR Electric (2.1) - (2.1) (0.5) - (0.5) Long-Term Derivative Liabilities: Level 3: Eversource $ (344.5) $ - $ (344.5) $ (337.1) $ - $ (337.1) CL&P (342.7) - (342.7) (336.2) - (336.2) NSTAR Electric (1.8) - (1.8) (0.9) - (0.9)
Rollforward Of Net Derivative Asset Liabilities Valued Using Unobservable Inputs [Table Text Block]	For the Three Months Ended March 31, 2016 2015 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (380.9) $ (380.8) $ (0.1) $ (415.4) $ (410.9) $ (4.5) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (28.9) (24.6) (4.3) (12.1) (12.1) - Settlements 22.1 20.3 1.8 20.7 19.7 1.0 Fair Value as of End of Period $ (387.7) $ (385.1) $ (2.6) $ (406.8) $ (403.3) $ (3.5)
Fairvalueinputsliabilitiesquantitativeinformationtabletextblock	As of March 31, 2016 As of December 31, 2015 Range Period Covered Range Period Covered Capacity Prices: Eversource $ 11.08 - 15.82 per kW-Month 2017 - 2026 $ 10.81 - 15.82 per kW-Month 2016 - 2026 CL&P $ 11.08 - 12.60 per kW-Month 2020 - 2026 $ 10.81 - 12.60 per kW-Month 2019 - 2026 NSTAR Electric $ 12.11 - 15.82 per kW-Month 2017 - 2018 $ 10.81 - 15.82 per kW-Month 2016 - 2019 Forward Reserve: Eversource, CL&P $ 2.00 per kW-Month 2016 - 2024 $ 2.00 per kW-Month 2016 - 2024 REC Prices: Eversource, NSTAR Electric $ 30 - 35 per REC 2016 - 2018 $ 45 - 51 per REC 2016 - 2018

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Available For Sale Securities Reconciliation [Table TextBlock]	As of March 31, 2016 As of December 31, 2015 Pre-Tax Pre-Tax Pre-Tax Pre-Tax Eversource Amortized Unrealized Unrealized Amortized Unrealized Unrealized (Millions of Dollars) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Debt Securities $ 257.9 $ 7.0 $ (0.1) $ 264.8 $ 256.5 $ 4.5 $ (0.6) $ 260.4 Equity Securities 214.7 42.0 (3.5) 253.2 215.3 59.2 (3.4) 271.1
Investments Classified by Contractual Maturity Date [Table Text Block]	Eversource Amortized (Millions of Dollars) Cost Fair Value Less than one year (1) $ 38.2 $ 38.2 One to five years 51.5 52.1 Six to ten years 42.7 44.4 Greater than ten years 125.5 130.1 Total Debt Securities $ 257.9 $ 264.8
Fair Value Heirarchy [Table Text Block]	Eversource (Millions of Dollars) As of March 31, 2016 As of December 31, 2015 Level 1: Mutual Funds and Equities $ 267.2 $ 285.3 Money Market Funds 32.1 26.9 Total Level 1 $ 299.3 $ 312.2 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 59.4 $ 46.6 Corporate Debt Securities 37.0 43.9 Asset-Backed Debt Securities 19.6 20.0 Municipal Bonds 108.0 111.4 Other Fixed Income Securities 8.7 11.6 Total Level 2 $ 232.7 $ 233.5 Total Marketable Securities $ 532.0 $ 545.7

Pension Benefits and Postreti28

Pension Benefits and Postretirement Benefits Other Than Pensions (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Net Benefit Costs [Table Text Block]	Pension and SERP Eversource For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 (1) Service Cost $ 19.4 $ 23.2 Interest Cost 46.5 56.6 Expected Return on Plan Assets (79.6) (84.3) Actuarial Loss 31.5 38.9 Prior Service Cost 0.9 0.9 Total Net Periodic Benefit Expense $ 18.7 $ 35.3 Capitalized Pension Expense $ 6.1 $ 9.6 PBOP Eversource For the Three Months Ended (Millions of Dollars) March 31, 2016 March 31, 2015 (1) Service Cost $ 3.1 $ 4.2 Interest Cost 9.7 11.9 Expected Return on Plan Assets (15.7) (16.8) Actuarial Loss 1.1 1.8 Prior Service Credit (0.1) (0.1) Total Net Periodic Benefit Expense/(Income) $ (1.9) $ 1.0 Capitalized PBOP Expense/(Income) $ (0.9) $ 0.2 Pension and SERP For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH (1) WMECO Service Cost $ 5.0 $ 3.4 $ 2.5 $ 0.9 $ 6.0 $ 3.8 $ 2.9 $ 1.1 Interest Cost 10.6 8.3 5.1 2.1 12.7 10.2 5.9 2.5 Expected Return on Plan Assets (18.2) (16.9) (9.7) (4.4) (19.7) (17.6) (10.0) (4.7) Actuarial Loss 6.7 8.4 2.5 1.4 8.2 9.6 3.0 1.6 Prior Service Cost 0.4 - 0.1 0.1 0.4 - 0.1 0.1 Total Net Periodic Benefit Expense $ 4.5 $ 3.2 $ 0.5 $ 0.1 $ 7.6 $ 6.0 $ 1.9 $ 0.6 Intercompany Allocations $ 3.3 $ 2.2 $ 1.0 $ 0.6 $ 6.4 $ 3.6 $ 1.7 $ 1.2 Capitalized Pension Expense $ 2.7 $ 1.8 $ 0.3 $ 0.2 $ 4.3 $ 2.8 $ 0.8 $ 0.5 PBOP For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH (1) WMECO Service Cost $ 0.5 $ 0.9 $ 0.3 $ 0.1 $ 0.6 $ 1.3 $ 0.4 $ 0.1 Interest Cost 1.4 4.0 0.8 0.3 1.8 4.8 1.0 0.4 Expected Return on Plan Assets (2.6) (6.4) (1.4) (0.6) (2.8) (6.8) (1.5) (0.6) Actuarial Loss 0.2 0.2 0.1 - 0.2 0.8 0.1 - Prior Service Credit - - - - - (0.1) - - Total Net Periodic Benefit Income $ (0.5) $ (1.3) $ (0.2) $ (0.2) $ (0.2) $ - $ - $ (0.1) Intercompany Allocations $ 0.2 $ 0.1 $ 0.0 $ 0.0 $ 0.5 $ 0.3 $ 0.1 $ 0.1 Capitalized PBOP Expense/(Income) $ (0.2) $ (0.6) $ 0.0 $ (0.1) $ 0.0 $ 0.1 $ - $ - (1) Amounts excluded approximately $1 million for the three months ended March 31, 2015 that represented amounts included in other deferred debits.

Environmental Matters (Tables)

Environmental Matters (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Environmental Loss Contingencies By Site Text Block	As of March 31, 2016 As of December 31, 2015 Reserve Reserve Number of Sites (in millions) Number of Sites (in millions) Eversource 64 $ 51.7 64 $ 51.1 CL&P 14 4.6 14 4.6 NSTAR Electric 15 2.3 15 2.4 PSNH 12 4.4 12 4.5 WMECO 4 0.6 4 0.6

Guarantees and Indemnifications

Guarantees and Indemnifications (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Guarantee Obligations Text Block	Maximum Exposure Company Description (in millions) Expiration Dates On behalf of subsidiaries: Eversource Gas Transmission LLC Access Northeast Project Capital Contributions Guarantee $ 187.9 2021 Various Surety Bonds (1) $ 38.7 2016 - 2018 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate $ 10.3 2019 and 2024

FAIR VALUE OF FINANCIAL INSTR31

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Fair Value By Balance Sheet Grouping Text Block	As of March 31, 2016 As of December 31, 2015 Eversource Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 155.8 $ 155.6 $ 157.9 Long-Term Debt 9,523.6 10,190.4 9,034.5 9,425.9 As of March 31, 2016 CL&P NSTAR Electric PSNH WMECO Carrying Fair Carrying Fair Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 113.7 $ 43.0 $ 42.1 $ - $ - $ - $ - Long-Term Debt 2,764.3 3,155.9 2,030.0 2,240.7 1,071.3 1,139.5 517.2 556.8 As of December 31, 2015 CL&P NSTAR Electric PSNH WMECO Carrying Fair Carrying Fair Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 114.9 $ 43.0 $ 43.0 $ - $ - $ - $ - Long-Term Debt 2,763.7 3,031.6 2,029.8 2,182.4 1,071.0 1,121.2 517.3 551.8

ACCUMULATED OTHER COMPREHENSI32

ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Accumulated Other Comprehensive Income Loss Table Text Block	For the Three Months Ended March 31, 2016 For the Three Months Ended March 31, 2015 Qualified Unrealized Qualified Unrealized Cash Flow Gains/(Losses) Defined Cash Flow Gains on Defined Eversource Hedging on Marketable Benefit Hedging Marketable Benefit (Millions of Dollars) Instruments Securities Plans Total Instruments Securities Plans Total Balance as of Beginning of Period $ (10.3) $ (1.9) $ (54.6) $ (66.8) $ (12.4) $ 0.7 $ (62.3) $ (74.0) OCI Before Reclassifications - 0.2 - 0.2 - 0.1 - 0.1 Amounts Reclassified from AOCI 0.5 - 0.9 1.4 0.5 - 1.0 1.5 Net OCI 0.5 0.2 0.9 1.6 0.5 0.1 1.0 1.6 Balance as of End of Period $ (9.8) $ (1.7) $ (53.7) $ (65.2) $ (11.9) $ 0.8 $ (61.3) $ (72.4)

COMMON SHARES (Tables)

COMMON SHARES (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule of Stock by Class [Text Block]	11 . COMMON SHARES The following table sets fo rth the E ve r s ource parent common shares and th e shares of common stock of CL&P, NSTAR Electric , PSNH and WMECO that were authorized and issued as well as the respective per share par values : Shares Authorized as of Per Share March 31, 2016 and Issued as of Par Value December 31, 2015 March 31, 2016 December 31, 2015 Eversource $ 5 380,000,000 333,878,402 333,862,615 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 100 100 PSNH $ 1 100,000,000 301 301 WMECO $ 25 1,072,471 434,653 434,653 As of both March 31, 2016 and December 31, 2015 , there were 16,671,366 E versour ce common shares held as treasury shares. As of March 31, 2016 and December 31, 2015 , Eversource common sha res outstanding were 317,207,036 and 317,191,249 , respectively .

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2016
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Earnings Per Share Basic And Diluted [Table Text Block]	Eversource For the Three Months Ended (Millions of Dollars, except share information) March 31, 2016 March 31, 2015 Net Income Attributable to Common Shareholders $ 244.2 $ 253.3 Weighted Average Common Shares Outstanding: Basic 317,517,141 317,090,841 Dilutive Effect 963,909 1,400,347 Diluted 318,481,050 318,491,188 Basic and Diluted EPS $ 0.77 $ 0.80

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting Information [Line Items]
Schedule Of Segment Reporting Information By Segment Text Block	For the Three Months Ended March 31, 2016 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,436.1 $ 342.6 $ 283.3 $ 214.2 $ (220.6) $ 2,055.6 Depreciation and Amortization (127.7) (15.8) (45.1) (6.9) 0.5 (195.0) Other Operating Expenses (1,088.9) (233.5) (73.0) (197.3) 220.6 (1,372.1) Operating Income 219.5 93.3 165.2 10.0 0.5 488.5 Interest Expense (48.0) (10.1) (28.0) (14.1) 2.0 (98.2) Other Income/(Loss), Net - (0.3) 2.6 305.5 (305.8) 2.0 Net Income Attributable to Common Shareholders $ 108.4 $ 50.9 $ 85.7 $ 302.5 $ (303.3) $ 244.2 Cash Flows Used for Investments in Plant $ 184.2 $ 52.1 $ 172.4 $ 22.8 $ - $ 431.5 For the Three Months Ended March 31, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,760.1 $ 507.4 $ 249.0 $ 240.0 $ (243.1) $ 2,513.4 Depreciation and Amortization (159.1) (18.2) (40.4) (7.2) 0.5 (224.4) Other Operating Expenses (1,342.8) (388.5) (74.1) (229.2) 243.1 (1,791.5) Operating Income 258.2 100.7 134.5 3.6 0.5 497.5 Interest Expense (47.6) (9.0) (27.6) (11.8) 1.2 (94.8) Other Income/(Loss), Net 2.2 (0.2) 2.9 314.9 (314.1) 5.7 Net Income Attributable to Common Shareholders $ 130.6 $ 55.6 $ 66.6 $ 312.9 $ (312.4) $ 253.3 Cash Flows Used for Investments in Plant $ 172.5 $ 30.0 $ 150.0 $ 10.1 $ - $ 362.6 The following table summarizes Eversource's segmented total assets: Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total As of March 31, 2016 $ 17,999.8 $ 3,134.1 $ 8,127.2 $ 13,335.6 $ (11,884.2) $ 30,712.5 As of December 31, 2015 17,981.3 3,104.5 8,019.3 13,256.7 (11,781.5) 30,580.3

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2016
Description of Consolidation of Yankee Companies	Eversource consolidates CYAPC and YAEC because CL&P's, NSTAR Electric's, PSNH's and WMECO's combined ownership interest in each of these entities is greater than 50 percent. Intercompany transactions between CL&P, NSTAR Electric, PSNH and WMECO and the CYAPC and YAEC companies have been eliminated in consolidation of the Eversource financial statements. Access Northeast is a natural gas pipeline and storage project (the "Project") being developed jointly by Eversource, Spectra Energy Corp and National Grid. Access Northeast will enhance the Algonquin and Maritimes & Northeast pipeline systems using existing routes. Eversource and Spectra Energy Corp each own a 40 percent interest in the Project, with the remaining 20 percent interest owned by National Grid. The total projected cost for both the pipeline and the LNG storage is expected to be approximately $3 billion, to be funded in proportion to ownership interest (approximately $1.2 billion by Eversource), with anticipated in-service dates commencing in November 2018. Eversource’s cumulative equity investment in the Project as of March 31, 2016 of $14.4 million is presented in Other Long-Term Assets.

ACCOUNTING STANDARDS (Details)

ACCOUNTING STANDARDS (Details) - USD ($) $ in Millions	Mar. 31, 2016	Mar. 31, 2015
Available for sale securities subject to new accounting guidance	$ 52
Impact of share based compensation accounting guidance on income tax	2.5
Impact of new accounting standard on cash flow statement	$ 9.1	$ 9.7

Provision for Uncollectible A38

Provision for Uncollectible Accounts (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	$ 197.6	$ 190.7
Uncollectible Hardship Accounts Receivable Reserve	118.9	118.5
The Connecticut Light And Power Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	84.9	79.5
Uncollectible Hardship Accounts Receivable Reserve	71.3	68.1
NSTAR Electric Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	51.5	52.6
Uncollectible Hardship Accounts Receivable Reserve	22.7	25.3
Public Service Company Of New Hampshire [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	9.1	8.7
Western Massachusetts Electric Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	13.6	14
Uncollectible Hardship Accounts Receivable Reserve	$ 7.1	$ 7.4

Other Taxes (Details)

Other Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Excise And Sales Taxes	$ 42.2	$ 41.9
The Connecticut Light And Power Company [Member]
Excise And Sales Taxes	$ 36	$ 33

Supplemental Cash Flow Inform40

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Capital Expenditures Incurred But Not Yet Paid	$ 125.6	$ 110.4
The Connecticut Light And Power Company [Member]
Capital Expenditures Incurred But Not Yet Paid	52.6	42.3
NSTAR Electric Company [Member]
Capital Expenditures Incurred But Not Yet Paid	11.7	21.9
Public Service Company Of New Hampshire [Member]
Capital Expenditures Incurred But Not Yet Paid	26.8	21.7
Western Massachusetts Electric Company [Member]
Capital Expenditures Incurred But Not Yet Paid	$ 10.7	$ 8.3

REGULATORY ACCOUNTING (Details)

REGULATORY ACCOUNTING (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Regulatory Asset [Line Items]
Regulatory Assets, Total	$ 4,622,800	$ 4,583,800
Regulatory Assets Current	919,311	845,843
Regulatory Assets Long Term	3,703,486	3,737,960
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	$ 76,100	75,300
Public Utilities Disclosure Of Regulatory Matters
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	$ 637,900	621,400
Regulatory Liability Current	111,414	107,759
Regulatory Liabilities Long-Term	526,452	513,595
The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,704,100	1,637,300
Regulatory Assets Current	324,559	268,318
Regulatory Assets Long Term	1,379,484	1,369,028
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	2,800	3,100
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	140,700	136,000
Regulatory Liability Current	62,999	61,155
Regulatory Liabilities Long-Term	77,744	74,830
NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,469,300	1,461,400
Regulatory Assets Current	361,307	348,408
Regulatory Assets Long Term	1,108,037	1,112,977
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	33,000	35,400
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	272,400	267,700
Regulatory Liability Current	4,997	3,281
Regulatory Liabilities Long-Term	267,440	264,352
Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	347,400	362,900
Regulatory Assets Current	101,633	104,971
Regulatory Assets Long Term	245,760	257,873
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	5,400	4,800
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	52,600	54,800
Regulatory Liability Current	4,723	6,898
Regulatory Liabilities Long-Term	47,930	47,851
Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	192,800	191,200
Regulatory Assets Current	61,363	56,166
Regulatory Assets Long Term	131,432	135,010
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	18,000	16,700
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	23,600	24,700
Regulatory Liability Current	9,760	13,122
Regulatory Liabilities Long-Term	13,775	11,597
Cost Of Removal [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	444,700	437,100
Cost Of Removal [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	26,700	24,100
Cost Of Removal [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	260,200	257,400
Cost Of Removal [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	47,300	47,200
Cost Of Removal [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	3,700	2,800
Regulatory Tracker Deferrals Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	101,100	99,700
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	49,700	56,200
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	4,500	3,300
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	2,600	3,400
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	10,900	12,900
AFUDC Transmission Incentive [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	65,900	66,100
AFUDC Transmission Incentive [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	51,200	51,500
AFUDC Transmission Incentive [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	5,800	5,700
AFUDC Transmission Incentive [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	8,900	8,900
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	26,200	18,500
Other Regulatory Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	13,100	4,200
Other Regulatory Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	1,900	1,300
Other Regulatory Liabilities [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	2,700	4,200
Other Regulatory Liabilities [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	100	100
Benefit Costs [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,796,200	1,828,200
Benefit Costs [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	406,300	413,600
Benefit Costs [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	471,400	479,900
Benefit Costs [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	161,500	164,200
Benefit Costs [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	83,400	84,900
Regulatory Assets Offsetting Derivative Liabilities [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	389,600	388,000
Regulatory Assets Offsetting Derivative Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	385,100	380,800
Regulatory Assets Offsetting Derivative Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	3,900	1,300
Regulatory Assets Offsetting Derivative Liabilities [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	0	0
Regulatory Assets Offsetting Derivative Liabilities [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	0	0
Deferred Income Tax Charges Member
Regulatory Asset [Line Items]
Regulatory Assets, Total	646,600	650,900
Deferred Income Tax Charges Member | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	444,300	444,400
Deferred Income Tax Charges Member | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	85,700	85,700
Deferred Income Tax Charges Member | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	29,900	34,500
Deferred Income Tax Charges Member | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	31,300	31,800
Storm Restoration Costs [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	450,500	436,900
Storm Restoration Costs [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	284,200	271,400
Storm Restoration Costs [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	118,300	110,900
Storm Restoration Costs [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	26,600	31,500
Storm Restoration Costs [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	21,400	23,100
Goodwill Regulatory Asset [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	479,800	484,900
Goodwill Regulatory Asset [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	411,900	416,300
Regulatory Tracker Deferrals Regulatory Assets [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	604,400	526,500
Regulatory Tracker Deferrals Regulatory Assets [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	104,300	45,100
Regulatory Tracker Deferrals Regulatory Assets [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	325,900	311,000
Regulatory Tracker Deferrals Regulatory Assets [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	98,100	101,200
Regulatory Tracker Deferrals Regulatory Assets [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	45,300	40,100
Unrecovered Contractual Obligations [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	130,400	134,400
Other Regulatory Assets [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	125,300	134,000
Other Regulatory Assets [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	79,900	82,000
Other Regulatory Assets [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	52,200	56,300
Other Regulatory Assets [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	31,300	31,500
Other Regulatory Assets [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	$ 11,400	$ 11,300

PROPERTY, PLANT AND ACCUMULAT42

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	$ 13,227,400	$ 13,054,800
Public Utilities Property Plant And Equipment Distribution Natural Gas	2,759,100	2,727,200
Public Utilities Property Plant And Equipment Transmission	7,725,300	7,691,900
Public Utilities Property Plant And Equipment Generation Or Processing	1,210,300	1,194,100
Public Utilities Property Plant And Equipment Electric And Natural Gas Utility Total	24,922,100	24,668,000
Public Utilities Property Plant And Equipment Other Property Plant And Equipment	575,500	558,600
Public Utilities Property Plant And Equipment Plant In Service	25,497,600	25,226,600
Less Accumulated Depreciation [Abstract]
Electric And Natural Gas Utility Accumulated Depreciation	(6,249,000)	(6,141,100)
Other Accumulated Depreciation	(264,800)	(255,600)
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(6,513,800)	(6,396,700)
Property Plant And Equipment Net Excluding Construction Work In Progress	18,983,800	18,829,900
Public Utilities Property Plant And Equipment Construction Work In Progress	1,112,900	1,062,500
Property, Plant and Equipment, Net	20,096,693	19,892,441
The Connecticut Light And Power Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	5,429,500	5,377,200
Public Utilities Property Plant And Equipment Transmission	3,631,300	3,618,000
Public Utilities Property Plant And Equipment Generation Or Processing	0	0
Public Utilities Property Plant And Equipment Plant In Service	9,060,800	8,995,200
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(2,073,700)	(2,041,900)
Property Plant And Equipment Net Excluding Construction Work In Progress	6,987,100	6,953,300
Public Utilities Property Plant And Equipment Construction Work In Progress	244,100	203,500
Property, Plant and Equipment, Net	7,231,214	7,156,809
NSTAR Electric Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	5,176,100	5,100,500
Public Utilities Property Plant And Equipment Transmission	2,137,700	2,131,300
Public Utilities Property Plant And Equipment Generation Or Processing	0	0
Public Utilities Property Plant And Equipment Plant In Service	7,313,800	7,231,800
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(1,924,400)	(1,886,800)
Property Plant And Equipment Net Excluding Construction Work In Progress	5,389,400	5,345,000
Public Utilities Property Plant And Equipment Construction Work In Progress	310,700	310,500
Property, Plant and Equipment, Net	5,700,068	5,655,458
Public Service Company Of New Hampshire [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	1,839,500	1,804,800
Public Utilities Property Plant And Equipment Transmission	936,100	928,200
Public Utilities Property Plant And Equipment Generation Or Processing	1,174,300	1,158,100
Public Utilities Property Plant And Equipment Plant In Service	3,949,900	3,891,100
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(1,192,000)	(1,171,000)
Property Plant And Equipment Net Excluding Construction Work In Progress	2,757,900	2,720,100
Public Utilities Property Plant And Equipment Construction Work In Progress	123,500	135,300
Property, Plant and Equipment, Net	2,881,435	2,855,363
Public Service Company Of New Hampshire [Member] | Generation Plant [Member]
Less Accumulated Depreciation [Abstract]
Electric And Natural Gas Utility Accumulated Depreciation	(531,700)
Western Massachusetts Electric Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	822,200	812,300
Public Utilities Property Plant And Equipment Transmission	971,000	964,900
Public Utilities Property Plant And Equipment Generation Or Processing	36,000	36,000
Public Utilities Property Plant And Equipment Plant In Service	1,829,200	1,813,200
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(317,000)	(307,000)
Property Plant And Equipment Net Excluding Construction Work In Progress	1,512,200	1,506,200
Public Utilities Property Plant And Equipment Construction Work In Progress	78,300	69,100
Property, Plant and Equipment, Net	$ 1,590,524	$ 1,575,306

DERIVATIVE INSTURMENTS (Details

DERIVATIVE INSTURMENTS (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)$ / KWmo	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)$ / KWmo$ / REC
Derivative Instrument Detail Abstract
Derivative Liabilities, Noncurrent	$ (344,458)		$ (337,102)
Other Derivatives Not Designated As Hedging Instruments At Fair Value Net Total Abstract
Description of Derivative Activity Volume	Commodity Supply and Price Risk Management: As required by regulation, CL&P, along with UI, has capacity-related contracts with generation facilities. CL&P has a sharing agreement with UI, with 80 percent of the costs or benefits of each contract borne by or allocated to CL&P and 20 percent borne by or allocated to UI. The combined capacity of these contracts is 787 MW. The capacity contracts extend through 2026 and obligate both CL&P and UI to make or receive payments on a monthly basis to or from the generation facilities based on the difference between a set capacity price and the capacity market price received in the ISO-NE capacity markets. In addition, CL&P has a contract to purchase 0.1 million MWh of energy per year through 2020. NSTAR Electric has a renewable energy contract to purchase 0.1 million MWh of energy per year through 2018 and a capacity-related contract to purchase up to 35 MW per year through 2019. As of March 31, 2016 and December 31, 2015, Eversource had NYMEX financial contracts for natural gas futures in order to reduce variability associated with the purchase price of approximately 5.3 million and 9.1 million MMBtu of natural gas, respectively.
Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net Abstract
Derivative Instruments Gain Loss Recognized In Regulatory Asset Liability	$ (30,500)	$ (16,600)
Derivative Credit Risk Related Contingent Features Abstract
Derivative Net Liability Position Aggregate Fair Value	(700)		(5,800)
Additional Collateral Aggregate Fair Value	$ 900		5,800
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsExitPricePremium	Exit price premiums of 5 percent through 22 percent are also applied on these contracts and reflect the uncertainty and illiquidity premiums that would be required based on the most recent market activity available for similar type contracts
The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	$ (92,953)		(91,820)
Derivative Liabilities, Noncurrent	(342,698)		(336,189)
Fair Value Inputs Level 2 [Member] | Subsidiaries [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	(700)		(5,800)
Derivative Assets Noncurrent			100
Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	6,200		5,800
Derivative Liabilities - Current	(95,100)		(92,300)
Derivative Liabilities, Noncurrent	(344,500)		(337,100)
Derivative Assets Noncurrent	$ 45,700		$ 42,700
Fair Value Inputs Level 3 [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	11.08		10.81
FairValueInputsRenewableEnergyCreditPrices | $ / KWmo	30		45
FairValueInputsForwardReserve | $ / KWmo	2		2
Fair Value Inputs Level 3 [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	15.82		15.82
FairValueInputsRenewableEnergyCreditPrices	35		51
FairValueInputsForwardReserve | $ / KWmo
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	$ 5,700		$ 5,800
Derivative Liabilities - Current	(93,000)		(91,800)
Derivative Liabilities, Noncurrent	(342,700)		(336,200)
Derivative Assets Noncurrent	$ 44,900		$ 41,400
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	11.08		10.81
FairValueInputsForwardReserve | $ / KWmo	2		2
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	12.60		12.60
FairValueInputsForwardReserve | $ / KWmo
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	$ 500
Derivative Liabilities - Current	(2,100)		$ (500)
Derivative Liabilities, Noncurrent	(1,800)		(900)
Derivative Assets Noncurrent	$ 800		$ 1,300
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	12.11		10.81
FairValueInputsRenewableEnergyCreditPrices	30		45
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	15.82		15.82
FairValueInputsRenewableEnergyCreditPrices	35		51
Amount Offset Against Derivatives [Member] | Fair Value Inputs Level 2 [Member] | Subsidiaries [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	$ 200
Amount Offset Against Derivatives [Member] | Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	(11,000)		$ (10,900)
Derivative Liabilities - Current	0
Derivative Assets Noncurrent	(16,900)		(19,300)
Amount Offset Against Derivatives [Member] | Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	(11,000)		(10,900)
Derivative Assets Noncurrent	(16,900)		(19,300)
Commodity [Member] | Fair Value Inputs Level 2 [Member] | Subsidiaries [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	(900)		(5,800)
Derivative Assets Noncurrent			100
Commodity [Member] | Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	17,200		16,700
Derivative Liabilities - Current	(95,100)		(92,300)
Derivative Liabilities, Noncurrent	(344,500)		(337,100)
Derivative Assets Noncurrent	62,600		62,000
Commodity [Member] | Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	16,700		16,700
Derivative Liabilities - Current	(93,000)		(91,800)
Derivative Liabilities, Noncurrent	(342,700)		(336,200)
Derivative Assets Noncurrent	61,800		60,700
Commodity [Member] | Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	500
Derivative Liabilities - Current	(2,100)		(500)
Derivative Liabilities, Noncurrent	(1,800)		(900)
Derivative Assets Noncurrent	$ 800		$ 1,300

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ (380.9)	$ (415.4)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	(28.9)	(12.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	22.1	20.7
Ending Balance	(387.7)	(406.8)
The Connecticut Light And Power Company [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	(380.8)	(410.9)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	(24.6)	(12.1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	20.3	19.7
Ending Balance	(385.1)	(403.3)
NSTAR Electric Company [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	(0.1)	(4.5)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	(4.3)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	1.8	1
Ending Balance	$ (2.6)	$ (3.5)

MARKETABLE SECURITIES (Details)

MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Marketable Securities, Restricted	$ 424.2		$ 436.9
Available For Sale Securities Debt Maturities Fair Value Abstract
Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value	44.4
Available For Sale Securities Debt Maturities After Ten Years Fair Value	130.1
Available For Sale Securities Debt Maturities After One Year Through Five Years Fair Value	52.1
Available For Sale Securities Debt Maturities Within One Year Fair Value	38.2
Available For Sale Securities Debt Maturities Fair Value	264.8
Available For Sale Securities Debt Maturities Amortized Cost Abstract
Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost	51.5
Available For Sale Securities Debt Maturities Within One Year Amortized Cost	38.2
Available For Sale Securities Debt Maturities After Ten Years Amortized Cost	125.5
Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost	42.7
Available For Sale Securities Debt Maturities Amortized Cost	257.9
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	532		545.7
TradingSecuritiesEquity	14		14.2
IncreaseDecreaseInTradingSecurities	0.2	$ 1.6
Fair Value Inputs Level 1 Member
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	299.3		312.2
Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	232.7		233.5
US Government Debt Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	59.4		46.6
Corporate Bond Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	37		43.9
Asset Backed Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	19.6		20
Municipal Bonds Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	108		111.4
Other Debt Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	8.7		11.6
Cash And Cash Equivalents Member | Fair Value Inputs Level 1 Member
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	32.1		26.9
Mutual Funds [Member] | Fair Value Inputs Level 1 Member
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	267.2		285.3
Debt Securities
Investments, Debt and Equity Securities [Abstract]
Available For Sale Securities Fair Value Disclosure	264.8		260.4
Available-for-sale Securities, Gross Unrealized Gains	7		4.5
AvailableForSaleSecuritiesGrossUnrealizedLoss	(0.1)		(0.6)
Available For Sale Securities Amortized Cost	257.9		256.5
Equity Securities
Investments, Debt and Equity Securities [Abstract]
Available For Sale Securities Fair Value Disclosure	253.2		271.1
Available-for-sale Securities, Gross Unrealized Gains	42		59.2
AvailableForSaleSecuritiesGrossUnrealizedLoss	(3.5)		(3.4)
Available For Sale Securities Amortized Cost	$ 214.7		$ 215.3

SHORT-TERM DEBT AND LONG-TERM D

SHORT-TERM DEBT AND LONG-TERM DEBT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Line of Credit Facility, Description	Commercial Paper Programs and Credit Agreements: Eversource parent has a $1.45 billion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. As of March 31, 2016 and December 31, 2015, Eversource parent had $621 million and approximately $1.1 billion, respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $829 million and $351.5 million of available borrowing capacity as of March 31, 2016 and December 31, 2015, respectively. The weighted-average interest rate on these borrowings as of March 31, 2016 and December 31, 2015 was 0.68 percent and 0.72 percent, respectively. As of March 31, 2016, there were intercompany loans from Eversource parent of $115.5 million to CL&P, $157.1 million to PSNH and $143.5 million to WMECO. As of December 31, 2015, there were intercompany loans from Eversource parent of $277.4 million to CL&P, $231.3 million to PSNH and $143.4 million to WMECO. Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas are parties to a five-year $1.45 billion revolving credit facility, which terminates on September 4, 2020. The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. NSTAR Electric has a $450 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. As of March 31, 2016 and December 31, 2015, NSTAR Electric had $148.5 million and $62.5 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $301.5 million and $387.5 million of available borrowing capacity as of March 31, 2016 and December 31, 2015, respectively. The weighted-average interest rate on these borrowings as of March 31, 2016 and December 31, 2015 was 0.38 percent and 0.40 percent, respectively. NSTAR Electric is a party to a five-year $450 million revolving credit facility, which terminates on September 4, 2020. The revolving credit facility serves to backstop NSTAR Electric's $450 million commercial paper program.
Notes Payable	$ 769,500	$ 1,160,953
Long-term Debt, Description	Long-Term Debt: Long-Term Debt: In March 2016, Eversource parent issued $250 million of 2.50 percent Series I Senior Notes due to mature in 2021 and $250 million of 3.35 percent Series J Senior Notes due to mature in 2026. The proceeds, net of issuance costs, were used to repay short-term borrowings under the Eversource parent commercial paper program.
The Connecticut Light And Power Company [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	$ 115,500	277,400
NSTAR Electric Company [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	450,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 301,500	$ 388,000
Short-term Debt, Weighted Average Interest Rate	0.38%	0.40%
CommercialPaper	$ 148,500	$ 63,000
Notes Payable	148,500	62,500
Public Service Company Of New Hampshire [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	157,100	231,300
Western Massachusetts Electric Company [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	143,500	143,400
Eversource Parent [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	1,450,000
Line of Credit Facility, Remaining Borrowing Capacity	829,000	351,500
Letters Of Credit Outstanding Under Line of Credit	$ 621,000	$ 1,100
Short-term Debt, Weighted Average Interest Rate	0.68%	0.72%

PENSION BENEFITS AND POSTRETI47

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	$ 1,355,422		$ 1,407,288
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Amount That Represents Deferred Regulatory Assets		$ 1,000
Impact of Change in Accounting Estimate Spot Rate Discount Rate	2,500
Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	19,400	23,200
Defined Benefit Plan Interest Cost	46,500	56,600
Defined Benefit Plan, Expected Return on Plan Assets	(79,600)	(84,300)
Defined Benefit Plan, Amortization of Gains (Losses)	31,500	38,900
Defined Benefit Plan Amortization Of Prior Service Cost Credit	900	900
Defined Benefit Plan Net Periodic Benefit Cost	18,700	35,300
Amount Capitalized Defined Benefit Expense	$ 6,100	9,600
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Service Cost Discount Rate Under Spot Rate	4.89%
Interest Cost Discount Rate under spot rate methodology	3.80%
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Impact of Change in Accounting Estimate Spot Rate Discount Rate	$ 12,000
PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	3,100	4,200
Defined Benefit Plan Interest Cost	9,700	11,900
Defined Benefit Plan, Expected Return on Plan Assets	(15,700)	(16,800)
Defined Benefit Plan, Amortization of Gains (Losses)	1,100	1,800
Defined Benefit Plan Amortization Of Prior Service Cost Credit	(100)	(100)
Defined Benefit Plan Net Periodic Benefit Cost	(1,900)	1,000
Amount Capitalized Defined Benefit Expense	$ (900)	200
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Service Cost Discount Rate Under Spot Rate	5.14%
Interest Cost Discount Rate under spot rate methodology	3.72%
The Connecticut Light And Power Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	$ 267,706		271,056
The Connecticut Light And Power Company [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	5,000	6,000
Defined Benefit Plan Interest Cost	10,600	12,700
Defined Benefit Plan, Expected Return on Plan Assets	(18,200)	(19,700)
Defined Benefit Plan, Amortization of Gains (Losses)	6,700	8,200
Defined Benefit Plan Amortization Of Prior Service Cost Credit	400	400
Defined Benefit Plan Net Periodic Benefit Cost	4,500	7,600
Related Intercompany Allocationsof Defined Benefit Expense	3,300	6,400
Amount Capitalized Defined Benefit Expense	2,700	4,300
The Connecticut Light And Power Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	500	600
Defined Benefit Plan Interest Cost	1,400	1,800
Defined Benefit Plan, Expected Return on Plan Assets	(2,600)	(2,800)
Defined Benefit Plan, Amortization of Gains (Losses)	200	200
Defined Benefit Plan Net Periodic Benefit Cost	(500)	(200)
Related Intercompany Allocationsof Defined Benefit Expense	200	500
Amount Capitalized Defined Benefit Expense	(200)	0
NSTAR Electric Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	188,974		209,153
NSTAR Electric Company [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	3,400	3,800
Defined Benefit Plan Interest Cost	8,300	10,200
Defined Benefit Plan, Expected Return on Plan Assets	(16,900)	(17,600)
Defined Benefit Plan, Amortization of Gains (Losses)	8,400	9,600
Defined Benefit Plan Amortization Of Prior Service Cost Credit	0	0
Defined Benefit Plan Net Periodic Benefit Cost	3,200	6,000
Related Intercompany Allocationsof Defined Benefit Expense	2,200	3,600
Amount Capitalized Defined Benefit Expense	1,800	2,800
NSTAR Electric Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	900	1,300
Defined Benefit Plan Interest Cost	4,000	4,800
Defined Benefit Plan, Expected Return on Plan Assets	(6,400)	(6,800)
Defined Benefit Plan, Amortization of Gains (Losses)	200	800
Defined Benefit Plan Net Periodic Benefit Cost	(1,300)	0
Related Intercompany Allocationsof Defined Benefit Expense	100	300
Amount Capitalized Defined Benefit Expense	(600)	100
Public Service Company Of New Hampshire [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	77,218		89,579
Public Service Company Of New Hampshire [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	2,500	2,900
Defined Benefit Plan Interest Cost	5,100	5,900
Defined Benefit Plan, Expected Return on Plan Assets	(9,700)	(10,000)
Defined Benefit Plan, Amortization of Gains (Losses)	2,500	3,000
Defined Benefit Plan Amortization Of Prior Service Cost Credit	100	100
Defined Benefit Plan Net Periodic Benefit Cost	500	1,900
Related Intercompany Allocationsof Defined Benefit Expense	1,000	1,700
Amount Capitalized Defined Benefit Expense	300	800
Public Service Company Of New Hampshire [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	300	400
Defined Benefit Plan Interest Cost	800	1,000
Defined Benefit Plan, Expected Return on Plan Assets	(1,400)	(1,500)
Defined Benefit Plan, Amortization of Gains (Losses)	100	100
Defined Benefit Plan Net Periodic Benefit Cost	(200)	0
Related Intercompany Allocationsof Defined Benefit Expense	0	100
Amount Capitalized Defined Benefit Expense	0	0
Western Massachusetts Electric Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	17,897		$ 19,515
Western Massachusetts Electric Company [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	900	1,100
Defined Benefit Plan Interest Cost	2,100	2,500
Defined Benefit Plan, Expected Return on Plan Assets	(4,400)	(4,700)
Defined Benefit Plan, Amortization of Gains (Losses)	1,400	1,600
Defined Benefit Plan Amortization Of Prior Service Cost Credit	100	100
Defined Benefit Plan Net Periodic Benefit Cost	100	600
Related Intercompany Allocationsof Defined Benefit Expense	600	1,200
Amount Capitalized Defined Benefit Expense	200	500
Western Massachusetts Electric Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	100	100
Defined Benefit Plan Interest Cost	300	400
Defined Benefit Plan, Expected Return on Plan Assets	(600)	(600)
Defined Benefit Plan, Amortization of Gains (Losses)	0	0
Defined Benefit Plan Net Periodic Benefit Cost	(200)	(100)
Related Intercompany Allocationsof Defined Benefit Expense	0	100
Amount Capitalized Defined Benefit Expense	$ (100)	$ 0

Environmental Matters (Details)

Environmental Matters (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Site Contingency [Line Items]
Environmental Site Quantity	64	64
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 51.1
Ending Balance	51.7	$ 51.1
MGP Site accrual [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	45.5
Ending Balance	$ 46.1	$ 45.5
The Connecticut Light And Power Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	14	14
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 4.6
Ending Balance	$ 4.6	$ 4.6
NSTAR Electric Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	15	15
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 2.4
Ending Balance	$ 2.3	$ 2.4
Public Service Company Of New Hampshire [Member]
Site Contingency [Line Items]
Environmental Site Quantity	12	12
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 4.5
Ending Balance	$ 4.4	$ 4.5
Western Massachusetts Electric Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	4	4
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 0.6
Ending Balance	$ 0.6	$ 0.6

Guarantees and Indemnificatio49

Guarantees and Indemnifications (Details) $ in Millions	Mar. 31, 2016USD ($)
Guarantee Of Financial Obligations Of Npt [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 25
Various Subsidiary Surety Bonds And Performance Guarantees Expiring Between 2016 And 2018 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	38.7
Guarantee Of Rocky River Reality And Nusco Lease Payments For Real Estate And Vehicles Expiring 2019 Through 2024 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	10.3
Access Northeast Project Capital Contributions Guarantee Expiring In 2021 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 187.9

Other Contingencies (Details)

Other Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Loss Contingencies [Line Items]
Loss Contingency, Description	C.        Spent Nuclear Fuel Litigation - Yankee Companies The Yankee Companies have filed separate complaints against the DOE in the Court of Federal Claims seeking monetary damages resulting from the DOE's failure to provide for a permanent facility to store spent nuclear fuel pursuant to the terms of the 1983 spent fuel and high level waste disposal contracts between the Yankee Companies and the DOE. The court had previously awarded the Yankee Companies damages for Phase I and Phase II of litigation resulting from the DOE's failure to meet its contractual obligations. Phase I covered damages incurred in the years 1998 through 2002 and Phase II covered damages incurred in the years 2001 through 2008 for CYAPC and YAEC and from 2002 through 2008 for MYAPC. DOE Phase III Damages - In August 2013, the Yankee Companies each filed subsequent lawsuits against the DOE seeking recovery of actual damages incurred in the years 2009 through 2012. The DOE Phase III trial concluded on July 1, 2015, followed by a post-trial briefing that concluded on October 14, 2015. On March 25, 2016, the court issued its decision, awarding CYAPC, YAEC and MYAPC damages of $32.6 million, $19.6 million and $24.6 million, respectively. In total, the Yankee Companies were awarded $76.8 million of the $77.9 million in damages sought by the Yankee Companies in Phase III. Any amounts refunded to Eversource utilities, which include CL&P, NSTAR Electric, PSNH and WMECO, will ultimately be refunded to utility customers. The parties have 60 days following the final judgment date to appeal. At this time, management cannot predict the timing or amount of damages that will ultimately be awarded. D.        FERC ROE Complaints FERC ROE Complaints I, II and III: Three separate complaints have been filed at FERC by combinations of New England state attorneys general, state regulatory commissions, consumer advocates, consumer groups, municipal parties and other parties (the "Complainants"). In these three separate complaints, the Complainants challenged the NETOs' base ROE of 11.14 percent that had been utilized since 2006 and sought an order to reduce it prospectively from the date of the final FERC order and for the 15-month complaint refund periods stipulated in the separate complaints. In 2014, the FERC ordered a 10.57 percent base ROE for the first complaint refund period and prospectively from October 16, 2014, and that a utility's total or maximum ROE shall not exceed the top of the new zone of reasonableness, which was set at 11.74 percent. In late 2014, the NETOs made a compliance filing, and the Company began issuing refunds to customers from the first complaint period. The Company has refunded all amounts associated with the first complaint period. As a result of developments in this matter, the Company recorded reserves across the complaint periods at its electric subsidiaries in the first quarter of 2015 and recognized a pre-tax charge to earnings (excluding interest) of $20 million, of which $12.5 million was recorded at CL&P, $2.4 million at NSTAR Electric, $1 million at PSNH, and $4.1 million at WMECO. The pre-tax charge was recorded as a regulatory liability and as a reduction to Operating Revenues. The NETOs and Complainants have filed appeals for the first complaint to the D.C. Circuit Court of Appeals. A court decision is expected in late 2016. For the second and third complaints, the state parties, municipal utilities and FERC trial staff each believe that the base ROE should be reduced to an amount lower than 10.57 percent. The NETOs believe that the Complainants' positions are without merit. On March 22, 2016, the FERC ALJ issued an initial decision on the second and third FERC ROE complaints. For the second complaint period, the FERC ALJ recommended a zone of reasonableness of 7.12 percent to 10.42 percent and a base ROE of 9.59 percent. For the third complaint period, the FERC ALJ recommended a zone of reasonableness of 7.04 percent to 12.19 percent and a base ROE of 10.90 percent. The FERC ALJ also affirmed that the maximum ROE for transmission incentive projects should be the top of the zone of reasonableness. The NETOs filed briefs on April 21, 2016, in which the NETOs identified corrections and requested changes that should be made to the FERC ALJ’s recommendations. A final FERC order is expected in late 2016 or early 2017. The Company believes that the range of potential loss for the second complaint period (the 15-month period beginning December 27, 2012) is from a base ROE of 10.57 percent to a base ROE of 9.59 percent. As the FERC ALJ initial decision on the third complaint recommended a base ROE of 10.90 percent, the Company concluded there is currently no range of potential loss for that complaint period. Given the differences between the recommended base ROEs in the FERC ALJ’s initial decision on the second and third complaints, as well as other factors, the Company is unable to predict the outcome of the final FERC order on these complaints. The Company does not believe any base ROE outcome within the 10.57 percent to 9.59 percent range is more likely than the base ROEs used to record the current revenues and reserves, and therefore the Company believes that the current reserves for the second complaint period are appropriate at this time. The impact of a 10 basis point change to the existing base ROE of 10.57 percent would affect Eversource's after-tax earnings by approximately $3 million for each of the 15-month second and third complaint periods.  If the Company adjusted its reserves based on the recommendations in the FERC ALJ initial decision (for both the base ROE and maximum ROE for transmission incentive projects) for the second and third complaints, then it would result in an after-tax increase of approximately $34 million and an after-tax decrease of approximately $8 million, respectively, to the existing reserves. FERC ROE Complaint IV: On April 29, 2016, a fourth complaint was filed with the FERC. At this time, the Company is unable to predict the outcome of this complaint. E.        PSNH Generation Restructuring On June 10, 2015, Eversource and PSNH entered into the 2015 Public Service Company of New Hampshire Restructuring and Rate Stabilization Agreement (the Agreement) with the New Hampshire Office of Energy and Planning, certain members of the NHPUC staff, the Office of Consumer Advocate, two State Senators, and several other parties. The Agreement was filed with the NHPUC on the same day. Under the terms of the Agreement, PSNH agreed to divest its generation assets upon NHPUC approval. The Agreement is designed to provide a resolution of issues pertaining to PSNH's generation assets in pending regulatory proceedings before the NHPUC. The Agreement provided for the Clean Air Project prudence proceeding to be resolved and all remaining Clean Air Project costs to be included in rates effective January 1, 2016. As part of the Agreement, PSNH agreed to forego recovery of $25 million of the deferred equity return related to the Clean Air Project. In addition, PSNH will not seek a general distribution rate increase effective before July 1, 2017 and will contribute $5 million to create a clean energy fund, which will not be recoverable from its customers. In 2015, PSNH recorded the $5 million contribution as a long-term liability and an increase to Operations and Maintenance expense on the statements of income. Upon completion of the divestiture process, all remaining stranded costs will be recovered via bonds that will be secured by a non-bypassable charge or through other recoveries in rates billed to PSNH customers. On January 26, 2016, Advisory Staff of the NHPUC and the parties to the Agreement filed a stipulation with the NHPUC agreeing that near-term divestiture of PSNH’s generation was in the public interest and that the Agreement should be approved. Implementation of the Agreement is subject to NHPUC approval, which is expected in 2016. If the NHPUC approves the settlements and the sale of the plants, the Company expects the plants will be sold in the first half of 2017. The sales price of the generating assets could be less than the carrying value, but the Company believes that full recovery of PSNH's generation assets is probable through a combination of cash flows during the remaining operating period, sales proceeds upon divestiture, and recovery of stranded costs in future rates.
Public Utilities Disclosure Of Regulatory Matters
FERC ROE Reserve - Cumulative - Pre Tax Charge [Member]
Loss Contingencies [Line Items]
Loss Contingency Loss in Period		$ 20
FERC ROE Reserve - Cumulative - Pre Tax Charge [Member] | The Connecticut Light And Power Company [Member]
Loss Contingencies [Line Items]
Loss Contingency Loss in Period		12.5
FERC ROE Reserve - Cumulative - Pre Tax Charge [Member] | NSTAR Electric Company [Member]
Loss Contingencies [Line Items]
Loss Contingency Loss in Period		2.4
FERC ROE Reserve - Cumulative - Pre Tax Charge [Member] | Public Service Company Of New Hampshire [Member]
Loss Contingencies [Line Items]
Loss Contingency Loss in Period		1
FERC ROE Reserve - Cumulative - Pre Tax Charge [Member] | Western Massachusetts Electric Company [Member]
Loss Contingencies [Line Items]
Loss Contingency Loss in Period		$ 4.1

FAIR VALUE OF FINANCIAL INSTR51

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	$ 155,568	$ 155,568
Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	155,600	155,600
Other Long Term Debt	9,523,600	9,034,500
Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	155,800	157,900
Other Long Term Debt	10,190,400	9,425,900
The Connecticut Light And Power Company [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	116,200	116,200
The Connecticut Light And Power Company [Member] | Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	116,200	116,200
Other Long Term Debt	2,764,300	2,763,700
The Connecticut Light And Power Company [Member] | Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	113,700	114,900
Other Long Term Debt	3,155,900	3,031,600
NSTAR Electric Company [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	43,000	43,000
NSTAR Electric Company [Member] | Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	43,000	43,000
Other Long Term Debt	2,030,000	2,029,800
NSTAR Electric Company [Member] | Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	42,100	43,000
Other Long Term Debt	2,240,700	2,182,400
Public Service Company Of New Hampshire [Member] | Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Long Term Debt	1,071,300	1,071,000
Public Service Company Of New Hampshire [Member] | Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Long Term Debt	1,139,500	1,121,200
Western Massachusetts Electric Company [Member] | Carrying Reported Amount Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Long Term Debt	517,200	517,300
Western Massachusetts Electric Company [Member] | Estimate Of Fair Value Fair Value Disclosure [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Other Long Term Debt	$ 556,800	$ 551,800

ACCUMULATED OTHER COMPREHENSI52

ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	$ (66,844)	$ (74,000)
Other Comprehensive Income Before Reclassifications, Net of Tax	200	100
Reclassification From OCI, Net Of Tax	1,400	1,500
Other Comprehensive Income (Loss), Net of Tax, Total	1,669	1,595
AOCI Ending Balance	(65,175)	(72,400)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(98,212)	(94,843)
Income Tax Expense	(146,302)	(153,226)
Net Income Attributable to Controlling Interests	244,153	253,254
The Connecticut Light And Power Company [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(576)
Other Comprehensive Income (Loss), Net of Tax, Total	120	115
AOCI Ending Balance	(456)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(36,498)	(36,624)
Income Tax Expense	(48,863)	(38,147)
Public Service Company Of New Hampshire [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(6,361)
Other Comprehensive Income (Loss), Net of Tax, Total	306	299
AOCI Ending Balance	(6,055)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(12,461)	(11,272)
Income Tax Expense	(22,326)	(20,276)
Western Massachusetts Electric Company [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(2,822)
Other Comprehensive Income (Loss), Net of Tax, Total	112	86
AOCI Ending Balance	(2,710)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(6,004)	(6,823)
Income Tax Expense	(10,076)	(9,113)
Qualified Cash Flow Hedging Instruments [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(10,300)	(12,400)
Reclassification From OCI, Net Of Tax	500	500
Other Comprehensive Income (Loss), Net of Tax, Total	500	500
AOCI Ending Balance	(9,800)	(11,900)
Unrealized Gains Losses on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(1,900)	700
Other Comprehensive Income Before Reclassifications, Net of Tax	200	100
Other Comprehensive Income (Loss), Net of Tax, Total	200	100
AOCI Ending Balance	(1,700)	800
Pension, SERP and PBOP Benefit Plans [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance	(54,600)	(62,300)
Other Comprehensive Income Before Reclassifications, Net of Tax	0	0
Reclassification From OCI, Net Of Tax	900	1,000
Other Comprehensive Income (Loss), Net of Tax, Total	900	1,000
AOCI Ending Balance	$ (53,700)	$ (61,300)

COMMON SHARES (Details)

COMMON SHARES (Details) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Class Of Stock [Line Items]
Common Stock Par Or Stated Value Per Share	$ 5	$ 5
Common Stock Shares Authorized	380,000,000	380,000,000
Common Stock Shares Issued	333,878,402	333,862,615
Treasury Stock Shares	16,671,366	16,671,366
Common Stock, Shares, Outstanding	317,207,036	317,191,249
The Connecticut Light And Power Company [Member]
Class Of Stock [Line Items]
Common Stock Par Or Stated Value Per Share	$ 10	$ 10
Common Stock Shares Authorized	24,500,000	24,500,000
Common Stock Shares Issued	6,035,205	6,035,205
NSTAR Electric Company [Member]
Class Of Stock [Line Items]
Common Stock Par Or Stated Value Per Share	$ 1	$ 1
Common Stock Shares Authorized	100,000,000	100,000,000
Common Stock Shares Issued	100	100
Public Service Company Of New Hampshire [Member]
Class Of Stock [Line Items]
Common Stock Par Or Stated Value Per Share	$ 1	$ 1
Common Stock Shares Authorized	100,000,000	100,000,000
Common Stock Shares Issued	301	301
Western Massachusetts Electric Company [Member]
Class Of Stock [Line Items]
Common Stock Par Or Stated Value Per Share	$ 25	$ 25
Common Stock Shares Authorized	1,072,471	1,072,471
Common Stock Shares Issued	434,653	434,653

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Notes To Consolidated Financial Statements [Abstract]
Net Income Attributable to Controlling Interests	$ 244,153	$ 253,254
Basic	317,517,141	317,090,841
Weighted Average Number Diluted Shares Outstanding Adjustment	963,909	1,400,347
Diluted	318,481,050	318,491,188
Earnings Per Share Basic And Diluted	$ 0.77	$ 0.80

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating Revenues	$ 2,055,635	$ 2,513,431
Operating Income	488,536	497,475
Total Interest Expense	(98,212)	(94,843)
Other Income/(Loss), Net	2,011	5,727
Income Tax Expense	(146,302)	(153,226)
Net Income	246,033	255,133
Net Income Attributable to Noncontrolling Interests	(1,880)	(1,879)
Net Income Attributable to Controlling Interests	244,153	253,254
Total Assets	30,712,475		$ 30,580,309
Investments in Property, Plant and Equipment	431,472	362,586
Electric Distribution Member
Segment Reporting Information [Line Items]
Operating Revenues	1,436,100	1,760,100
Depreciation And Amortization	(127,700)	(159,100)
Operating Expenses, Other	(1,088,900)	(1,342,800)
Operating Income	219,500	258,200
Total Interest Expense	(48,000)	(47,600)
Other Income/(Loss), Net	0	2,200
Net Income Attributable to Controlling Interests	108,400	130,600
Total Assets	17,999,800		17,981,300
Investments in Property, Plant and Equipment	184,200	172,500
Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Operating Revenues	342,600	507,400
Depreciation And Amortization	(15,800)	(18,200)
Operating Expenses, Other	(233,500)	(388,500)
Operating Income	93,300	100,700
Total Interest Expense	(10,100)	(9,000)
Other Income/(Loss), Net	(300)	(200)
Net Income Attributable to Controlling Interests	50,900	55,600
Total Assets	3,134,100		3,104,500
Investments in Property, Plant and Equipment	52,100	30,000
Electric Transmission [Member]
Segment Reporting Information [Line Items]
Operating Revenues	283,300	249,000
Depreciation And Amortization	(45,100)	(40,400)
Operating Expenses, Other	(73,000)	(74,100)
Operating Income	165,200	134,500
Total Interest Expense	(28,000)	(27,600)
Other Income/(Loss), Net	2,600	2,900
Net Income Attributable to Controlling Interests	85,700	66,600
Total Assets	8,127,200		8,019,300
Investments in Property, Plant and Equipment	172,400	150,000
Other Segment [Member]
Segment Reporting Information [Line Items]
Operating Revenues	214,200	240,000
Depreciation And Amortization	(6,900)	(7,200)
Operating Expenses, Other	(197,300)	(229,200)
Operating Income	10,000	3,600
Total Interest Expense	(14,100)	(11,800)
Other Income/(Loss), Net	305,500	314,900
Net Income Attributable to Controlling Interests	302,500	312,900
Total Assets	13,335,600		13,256,700
Investments in Property, Plant and Equipment	22,800	10,100
Eliminations Segment [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(220,600)	(243,100)
Depreciation And Amortization	500	500
Operating Expenses, Other	220,600	243,100
Operating Income	500	500
Total Interest Expense	2,000	1,200
Other Income/(Loss), Net	(305,800)	(314,100)
Net Income Attributable to Controlling Interests	(303,300)	(312,400)
Total Assets	(11,884,200)		(11,781,500)
Investments in Property, Plant and Equipment	0	0
Total [Member]
Segment Reporting Information [Line Items]
Operating Revenues	2,055,600	2,513,400
Depreciation And Amortization	(195,000)	(224,400)
Operating Expenses, Other	(1,372,100)	(1,791,500)
Operating Income	488,500	497,500
Total Interest Expense	(98,200)	(94,800)
Other Income/(Loss), Net	2,000	5,700
Net Income Attributable to Controlling Interests	244,200	253,300
Total Assets	30,712,500		$ 30,580,300
Investments in Property, Plant and Equipment	$ 431,500	$ 362,600