The Connecticut Light and Power Company (CNLTN) 10-Q 6 Nov 15 2015 Q3 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION	9 Months Ended
	Sep. 30, 2015USD ($)shares
Document And Entity [Line Items]
Entity Registrant Name	Eversource Energy
Document Period End Date	Sep. 30, 2015
Document Type	10-Q
Entity Central Index Key	72,741
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding	317,191,249
Entity Public Float | $	$ 14,272,287,390
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	2,015
Document Fiscal Period Focus	Q3
Amendment Flag	false
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	Sep. 30, 2015	Dec. 31, 2014
Current Assets:
Cash	$ 35,781	$ 38,703
Receivables, Net	928,064	856,346
Unbilled Revenues	197,920	211,758
Taxes Receivable	12,247	337,307
Fuel, Materials and Supplies	302,225	349,664
Regulatory Assets Current	653,892	672,493
Marketable Securities - Current	119,702	124,173
Prepayments and Other Current Assets	117,857	102,021
Total Current Assets	2,367,688	2,692,465
Property, Plant and Equipment, Net	19,406,025	18,647,041
Deferred Debits and Other Assets:
Regulatory Assets Long Term	3,951,752	4,054,086
Goodwill	3,519,401	3,519,401
Marketable Securities	476,778	515,025
Other Long-Term Assets	324,382	349,957
Total Deferred Debits and Other Assets	8,272,313	8,438,469
Total Assets	30,046,026	29,777,975
Current Liabilities:
Notes Payable	1,015,500	956,825
Long-Term Debt - Current Portion	228,883	245,583
Accounts Payable - Current	610,753	868,231
Obligations to Third Party Suppliers	157,798	115,632
Regulatory Liability Current	226,061	235,022
Deferred Tax Liabilities Current	169,272	160,288
Other Liabilities - Current	563,426	552,800
Total Current Liabilities	2,971,693	3,134,381
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	4,612,828	4,467,473
Regulatory Liabilities Long-Term	517,595	515,144
Long-Term Derivative Liabilities	365,692	409,632
Accrued Pension, SERP and PBOP	1,498,346	1,638,558
Other Long-Term Liabilities	872,376	874,387
Total Deferred Credits and Other Liabilities	7,866,837	7,905,194
Capitalization:
Long-Term Debt	8,757,498	8,606,017
Noncontrolling Interest in Consolidated Subsidiary:
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	155,568	155,568
Common Shareholders' Equity:
Common Stock	1,669,313	1,666,796
Capital Surplus, Paid In	6,260,663	6,235,834
Retained Earnings	2,747,977	2,448,661
Accumulated Other Comprehensive Loss	(73,546)	(74,009)
Treasury Stock	(309,977)	(300,467)
Common Shareholders' Equity	10,294,430	9,976,815
Total Capitalization	19,207,496	18,738,400
Total Liabilities and Capitalization	30,046,026	29,777,975
The Connecticut Light And Power Company [Member]
Current Assets:
Cash	13,407	2,356
Receivables, Net	425,955	355,140
Accounts Receivable from Affiliated Companies	28,266	16,757
Unbilled Revenues	96,301	102,137
Taxes Receivable	0	116,148
Regulatory Assets Current	243,293	220,344
Materials and Supplies	44,306	46,664
Prepaid Taxes	52,351	15,597
Prepayments and Other Current Assets	16,239	22,225
Total Current Assets	920,118	897,368
Property, Plant and Equipment, Net	7,008,603	6,809,664
Deferred Debits and Other Assets:
Regulatory Assets Long Term	1,420,974	1,475,508
Other Long-Term Assets	145,031	177,568
Total Deferred Debits and Other Assets	1,566,005	1,653,076
Total Assets	9,494,726	9,360,108
Current Liabilities:
Notes Payable To Affiliated Companies	0	133,400
Long-Term Debt - Current Portion	0	162,000
Accounts Payable - Current	207,366	272,971
Accounts Payable to Affiliated Companies	93,257	65,594
Obligations to Third Party Suppliers	75,659	73,624
Regulatory Liability Current	136,393	124,722
Accrued Taxes	47,973	4,091
Derivative Liabilities - Current	91,372	88,459
Other Liabilities - Current	124,504	149,329
Total Current Liabilities	776,524	1,074,190
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,636,831	1,642,805
Regulatory Liabilities Long-Term	76,864	81,298
Long-Term Derivative Liabilities	364,691	406,199
Accrued Pension, SERP and PBOP	284,890	273,854
Other Long-Term Liabilities	143,642	148,844
Total Deferred Credits and Other Liabilities	2,506,918	2,553,000
Capitalization:
Long-Term Debt	2,975,316	2,679,951
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	1,910,651	1,804,869
Retained Earnings	1,149,500	1,072,477
Accumulated Other Comprehensive Loss	(735)	(931)
Common Shareholders' Equity	3,119,768	2,936,767
Total Capitalization	6,211,284	5,732,918
Total Liabilities and Capitalization	9,494,726	9,360,108
NSTAR Electric Company [Member]
Current Assets:
Cash	2,809	12,773
Receivables, Net	303,969	234,481
Accounts Receivable from Affiliated Companies	17,229	40,353
Unbilled Revenues	43,288	29,741
Taxes Receivable	0	144,601
Fuel, Materials and Supplies	52,315	74,179
Regulatory Assets Current	223,520	198,710
Prepayments and Other Current Assets	8,862	10,815
Total Current Assets	651,992	745,653
Property, Plant and Equipment, Net	5,545,082	5,335,436
Deferred Debits and Other Assets:
Regulatory Assets Long Term	1,179,996	1,179,100
Other Long-Term Assets	60,339	73,051
Total Deferred Debits and Other Assets	1,240,335	1,252,151
Total Assets	7,437,409	7,333,240
Current Liabilities:
Notes Payable	258,500	302,000
Long-Term Debt - Current Portion	200,000	4,700
Accounts Payable - Current	172,521	217,311
Accounts Payable to Affiliated Companies	25,515	63,517
Obligations to Third Party Suppliers	70,607	34,824
Renewable Portfolio Standards Compliance Obligation	67,828	35,698
Regulatory Liability Current	12,319	49,611
Accrued Taxes	66,474	4,191
Deferred Tax Liabilities Current	92,183	55,136
Other Liabilities - Current	88,905	111,800
Total Current Liabilities	1,054,852	878,788
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,546,801	1,527,667
Regulatory Liabilities Long-Term	267,342	262,738
Accrued Pension, SERP and PBOP	211,891	235,529
Other Long-Term Liabilities	122,026	129,279
Total Deferred Credits and Other Liabilities	2,148,060	2,155,213
Capitalization:
Long-Term Debt	1,592,727	1,792,712
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	994,130
Retained Earnings	1,603,134	1,468,955
Accumulated Other Comprehensive Loss	258	442
Common Shareholders' Equity	2,598,770	2,463,527
Total Capitalization	4,234,497	4,299,239
Total Liabilities and Capitalization	7,437,409	7,333,240
Public Service Company Of New Hampshire [Member]
Current Assets:
Cash	2,103	489
Receivables, Net	91,700	80,151
Accounts Receivable from Affiliated Companies	14,630	3,194
Unbilled Revenues	34,932	40,181
Fuel, Materials and Supplies	143,983	148,139
Regulatory Assets Current	89,513	111,705
Prepayments and Other Current Assets	22,125	42,392
Total Current Assets	398,986	426,251
Property, Plant and Equipment, Net	2,768,206	2,635,844
Deferred Debits and Other Assets:
Regulatory Assets Long Term	272,360	293,115
Other Long-Term Assets	35,075	39,228
Total Deferred Debits and Other Assets	307,435	332,343
Total Assets	3,474,627	3,394,438
Current Liabilities:
Notes Payable To Affiliated Companies	137,300	90,500
Accounts Payable - Current	76,330	93,349
Accounts Payable to Affiliated Companies	25,239	33,734
Regulatory Liability Current	11,338	16,044
Deferred Tax Liabilities Current	34,699	36,164
Other Liabilities - Current	47,589	38,969
Total Current Liabilities	332,495	308,760
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	629,055	587,292
Regulatory Liabilities Long-Term	49,680	51,372
Accrued Pension, SERP and PBOP	97,167	93,243
Other Long-Term Liabilities	48,543	50,155
Total Deferred Credits and Other Liabilities	824,445	782,062
Capitalization:
Long-Term Debt	1,076,336	1,076,286
Common Shareholders' Equity:
Common Stock	0	0
Capital Surplus, Paid In	748,634	748,240
Retained Earnings	499,450	486,459
Accumulated Other Comprehensive Loss	(6,733)	(7,369)
Common Shareholders' Equity	1,241,351	1,227,330
Total Capitalization	2,317,687	2,303,616
Total Liabilities and Capitalization	3,474,627	3,394,438
Western Massachusetts Electric Company [Member]
Current Assets:
Cash	658	0
Receivables, Net	62,889	51,066
Accounts Receivable from Affiliated Companies	24,221	7,851
Unbilled Revenues	14,517	15,146
Taxes Receivable	49	18,126
Regulatory Assets Current	48,805	51,923
Marketable Securities - Current	40,459	28,658
Prepayments and Other Current Assets	6,983	7,607
Total Current Assets	198,581	180,377
Property, Plant and Equipment, Net	1,531,705	1,461,321
Deferred Debits and Other Assets:
Regulatory Assets Long Term	133,697	146,307
Marketable Securities	17,888	29,452
Other Long-Term Assets	26,709	22,018
Total Deferred Debits and Other Assets	178,294	197,777
Total Assets	1,908,580	1,839,475
Current Liabilities:
Notes Payable To Affiliated Companies	126,200	21,400
Long-Term Debt - Current Portion	0	50,000
Accounts Payable - Current	33,960	53,732
Accounts Payable to Affiliated Companies	21,496	14,328
Regulatory Liability Current	24,267	22,486
Deferred Tax Liabilities Current	13,403	18,089
Other Liabilities - Current	28,961	24,080
Total Current Liabilities	248,287	204,115
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	422,753	416,822
Regulatory Liabilities Long-Term	11,926	10,835
Accrued Pension, SERP and PBOP	18,320	17,705
Other Long-Term Liabilities	36,849	33,747
Total Deferred Credits and Other Liabilities	489,848	479,109
Capitalization:
Long-Term Debt	577,781	578,471
Common Shareholders' Equity:
Common Stock	10,866	10,866
Capital Surplus, Paid In	391,398	391,256
Retained Earnings	193,344	178,834
Accumulated Other Comprehensive Loss	(2,944)	(3,176)
Common Shareholders' Equity	592,664	577,780
Total Capitalization	1,170,445	1,156,251
Total Liabilities and Capitalization	$ 1,908,580	$ 1,839,475

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenues	$ 1,933,105	$ 1,892,532	$ 6,263,597	$ 5,860,736
Operating Expenses:
Purchased Power and Transmission	702,640	716,631	2,549,807	2,318,993
Operations and Maintenance	327,283	344,092	977,306	1,069,015
Depreciation	167,884	153,210	495,389	456,224
Amortization of Regulatory Assets/(Liabilities), Net	(16,851)	(22,531)	42,587	31,826
Energy Efficiency Programs	132,107	118,693	380,559	360,228
Taxes Other Than Income Taxes	150,804	141,527	439,221	421,862
Total Operating Expenses	1,463,867	1,451,622	4,884,869	4,658,148
Operating Income	469,238	440,910	1,378,728	1,202,588
Interest Expense:
Total Interest Expense	92,534	89,738	279,635	272,208
Other Income/(Loss), Net	5,241	11,860	23,866	19,054
Income Before Income Tax Expense	381,945	363,032	1,122,959	949,434
Income Tax Expense	144,146	126,539	420,640	345,858
Net Income	237,799	236,493	702,319	603,576
Net Income Attributable to Noncontrolling Interests	1,879	1,879	5,639	5,639
Net Income Attributable to Controlling Interests	$ 235,920	$ 234,614	$ 696,680	$ 597,937
Basic Earnings Per Common Share	$ 0.74	$ 0.74	$ 2.20	$ 1.89
Diluted Earnings Per Common Share	0.74	0.74	2.19	1.89
Common Stock Dividends Per Share Declared	$ 0.42	$ 0.39	$ 1.25	$ 1.18
Weighted Average Common Shares Outstanding:
Basic	317,452,212	316,340,691	317,296,107	315,941,904
Diluted	318,405,269	317,554,925	318,396,042	317,186,490
The Connecticut Light And Power Company [Member]
Operating Revenues	$ 704,262	$ 695,642	$ 2,175,733	$ 2,017,580
Operating Expenses:
Purchased Power and Transmission	274,762	255,787	861,562	736,952
Operations and Maintenance	122,280	127,285	358,324	368,562
Depreciation	54,809	46,886	159,903	139,598
Amortization of Regulatory Assets/(Liabilities), Net	(22,859)	13,098	17,917	62,644
Energy Efficiency Programs	42,590	41,399	119,360	119,389
Taxes Other Than Income Taxes	71,563	64,994	201,743	194,105
Total Operating Expenses	543,145	549,449	1,718,809	1,621,250
Operating Income	161,117	146,193	456,924	396,330
Interest Expense:
Total Interest Expense	36,716	38,735	109,463	110,448
Other Income/(Loss), Net	2,356	6,456	8,576	10,658
Income Before Income Tax Expense	126,757	113,914	356,037	296,540
Income Tax Expense	46,569	30,038	127,845	95,980
Net Income	80,188	83,876	228,192	200,560
NSTAR Electric Company [Member]
Operating Revenues	750,724	727,909	2,134,728	1,955,609
Operating Expenses:
Purchased Power and Transmission	299,040	317,784	984,035	879,773
Operations and Maintenance	83,486	79,705	228,740	244,610
Depreciation	49,101	47,455	146,818	140,996
Amortization of Regulatory Assets/(Liabilities), Net	2,257	(15,063)	(10,643)	(916)
Energy Efficiency Programs	67,693	56,915	164,843	145,499
Taxes Other Than Income Taxes	34,982	34,513	95,821	99,121
Total Operating Expenses	536,559	521,309	1,609,614	1,509,083
Operating Income	214,165	206,600	525,114	446,526
Interest Expense:
Total Interest Expense	18,992	17,338	57,218	59,091
Other Income/(Loss), Net	513	3,287	3,649	3,011
Income Before Income Tax Expense	195,686	192,549	471,545	390,446
Income Tax Expense	77,062	76,975	187,397	156,655
Net Income	118,624	115,574	284,148	233,791
Public Service Company Of New Hampshire [Member]
Operating Revenues	234,364	223,664	761,086	735,123
Operating Expenses:
Purchased Power and Transmission	53,017	64,397	200,533	247,992
Operations and Maintenance	65,190	65,563	200,085	198,025
Depreciation	26,592	24,568	77,989	73,247
Amortization of Regulatory Assets/(Liabilities), Net	1,967	(9,734)	29,148	(17,565)
Energy Efficiency Programs	3,873	3,766	11,001	10,897
Taxes Other Than Income Taxes	20,104	18,702	61,435	53,051
Total Operating Expenses	170,743	167,262	580,191	565,647
Operating Income	63,621	56,402	180,895	169,476
Interest Expense:
Total Interest Expense	11,647	11,024	34,582	33,995
Other Income/(Loss), Net	685	461	2,313	1,673
Income Before Income Tax Expense	52,659	45,839	148,626	137,154
Income Tax Expense	20,158	17,603	56,135	52,199
Net Income	32,501	28,236	92,491	84,955
Western Massachusetts Electric Company [Member]
Operating Revenues	125,093	118,145	403,151	363,843
Operating Expenses:
Purchased Power and Transmission	36,465	43,926	149,182	130,977
Operations and Maintenance	21,762	20,820	61,651	67,085
Depreciation	11,196	10,506	32,420	31,144
Amortization of Regulatory Assets/(Liabilities), Net	3,930	(8,519)	11,194	(7,778)
Energy Efficiency Programs	12,107	10,983	32,701	33,096
Taxes Other Than Income Taxes	9,599	9,200	28,430	25,679
Total Operating Expenses	95,059	86,916	315,578	280,203
Operating Income	30,034	31,229	87,573	83,640
Interest Expense:
Total Interest Expense	5,901	6,576	19,014	18,929
Other Income/(Loss), Net	587	502	2,406	1,670
Income Before Income Tax Expense	24,720	25,155	70,965	66,381
Income Tax Expense	9,749	10,490	28,555	26,596
Net Income	$ 14,971	$ 14,665	$ 42,410	$ 39,785

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net Income	$ 237,799	$ 236,493	$ 702,319	$ 603,576
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	526	509	1,544	1,528
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(2,803)	(216)	(3,919)	242
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	764	1,042	2,838	4,089
Other Comprehensive Income (Loss), Net of Tax, Total	(1,513)	1,335	463	5,859
Comprehensive Income Attributable to Noncontrolling Interests	(1,879)	(1,879)	(5,639)	(5,639)
Comprehensive Income	234,407	235,949	697,143	603,796
The Connecticut Light And Power Company [Member]
Net Income	80,188	83,876	228,192	200,560
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	111	111	333	333
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(98)	(7)	(137)	8
Other Comprehensive Income (Loss), Net of Tax, Total	13	104	196	341
Comprehensive Income	80,201	83,980	228,388	200,901
NSTAR Electric Company [Member]
Net Income	118,624	115,574	284,148	233,791
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	(2)		(184)
Other Comprehensive Income (Loss), Net of Tax, Total	(2)		(184)
Comprehensive Income	118,622	115,574	283,964	233,791
Public Service Company Of New Hampshire [Member]
Net Income	32,501	28,236	92,491	84,955
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	291	290	872	871
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(169)	(13)	(236)	14
Other Comprehensive Income (Loss), Net of Tax, Total	122	277	636	885
Comprehensive Income	32,623	28,513	93,127	85,840
Western Massachusetts Electric Company [Member]
Net Income	14,971	14,665	42,410	39,785
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease Abstract
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	101	85	270	254
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(27)	(2)	(38)	2
Other Comprehensive Income (Loss), Net of Tax, Total	74	83	232	256
Comprehensive Income	$ 15,045	$ 14,748	$ 42,642	$ 40,041

CONSOLIDATED STATEMENT OF CASH

CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities:
Net Income	$ 702,319	$ 603,576
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	495,389	456,224
Deferred Income Tax Expense (Benefit)	153,353	64,755
Pension, SERP and PBOP Expense	71,802	74,296
Pension and PBOP Contributions	(162,880)	(74,681)
Regulatory Over/(Under) Recoveries, Net	31,874	290,111
Amortization of Regulatory Assets/(Liabilities), Net	42,587	31,826
Proceeds from DOE Damages Claim, Net	0	132,138
Other	(49,548)	(17,096)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(148,442)	(66,463)
Increase Decrease in Fuel, Materials and Supplies	47,380	(27,147)
Taxes Receivable/(Accrued)	383,047	26,533
Accounts Payable	(233,660)	(69,448)
Other Current Assets and Liabilities, Net	8,370	(20,607)
Net Cash Flows Provided by Operating Activities	1,341,591	1,404,017
Investing Activities:
Investments in Property, Plant and Equipment	(1,177,285)	(1,117,493)
Proceeds from Sales of Marketable Securities	556,582	388,352
Purchases of Marketable Securities	(535,044)	(389,406)
Other Investing Activities	(2,769)	(4,669)
Net Cash Flows Used in Investing Activities	(1,158,516)	(1,123,216)
Financing Activities:
Cash Dividends on Common Stock	(397,363)	(356,080)
Cash Dividends on Preferred Stock	(5,639)	(5,639)
Increase/(Decrease) in Short-Term Debt	(387,575)	6,000
Issuance of Long-Term Debt	825,000	650,000
Retirements of Long-Term Debt	(216,700)	(576,650)
Other Financing Activities	(3,720)	(90)
Net Cash Flows Provided by/(Used in) Financing Activities	(185,997)	(282,459)
Net Increase/(Decrease) in Cash	(2,922)	(1,658)
Cash - Beginning of Year	38,703	43,364
Cash - End of Year	35,781	41,706
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	228,192	200,560
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	159,903	139,598
Deferred Income Tax Expense (Benefit)	(11,011)	(14,400)
Pension, SERP and PBOP Expense, Net of Contributions	10,654	8,050
Regulatory Over/(Under) Recoveries, Net	12,504	62,929
Amortization of Regulatory Assets/(Liabilities), Net	17,917	62,644
Proceeds from DOE Damages Claim		68,610
Other	(13,048)	(11,290)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(91,842)	(87,922)
Taxes Receivable/(Accrued)	160,031	39,805
Accounts Payable	(20,485)	16,984
Other Current Assets and Liabilities, Net	(31,044)	(2,575)
Net Cash Flows Provided by Operating Activities	421,771	482,993
Investing Activities:
Investments in Property, Plant and Equipment	(359,339)	(371,660)
Other Investing Activities	(740)	(4,539)
Net Cash Flows Used in Investing Activities	(360,079)	(376,199)
Financing Activities:
Cash Dividends on Common Stock	(147,000)	(128,400)
Cash Dividends on Preferred Stock	(4,169)	(4,169)
Issuance of Long-Term Debt	300,000	250,000
Increase/(Decrease) in Notes Payable to Affiliate	(133,400)	(181,900)
Retirements of Long-Term Debt	(162,000)	(150,000)
Capital Contributions from NU Parent	105,000	120,000
Other Financing Activities	(9,072)	(3,268)
Net Cash Flows Provided by/(Used in) Financing Activities	(50,641)	(97,737)
Net Increase/(Decrease) in Cash	11,051	9,057
Cash - Beginning of Year	2,356	7,237
Cash - End of Year	13,407	16,294
NSTAR Electric Company [Member]
Operating Activities:
Net Income	284,148	233,791
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	146,818	140,996
Deferred Income Tax Expense (Benefit)	54,188	(39,399)
Pension, SERP and PBOP Expense, Net of Contributions	(1,138)	(11,046)
Regulatory Over/(Under) Recoveries, Net	(48,903)	155,357
Amortization of Regulatory Assets/(Liabilities), Net	(10,643)	(916)
Proceeds from DOE Damages Claim		30,193
Other	(34,223)	(41,601)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(107,711)	(47,770)
Increase Decrease in Fuel, Materials and Supplies	21,863	(20,837)
Taxes Receivable/(Accrued)	207,516	60,252
Accounts Payable	(41,447)	(40,594)
Accounts Payable Related Parties	(14,878)	66,758
Other Current Assets and Liabilities, Net	46,671	32,340
Net Cash Flows Provided by Operating Activities	502,261	517,524
Investing Activities:
Investments in Property, Plant and Equipment	(314,055)	(309,248)
Net Cash Flows Used in Investing Activities	(314,055)	(309,248)
Financing Activities:
Cash Dividends on Common Stock	(148,500)	(253,000)
Cash Dividends on Preferred Stock	(1,470)	(1,470)
Increase/(Decrease) in Short-Term Debt	(43,500)	56,000
Issuance of Long-Term Debt	0	300,000
Retirements of Long-Term Debt	(4,700)	(301,650)
Other Financing Activities	0	(5,137)
Net Cash Flows Provided by/(Used in) Financing Activities	(198,170)	(205,257)
Net Increase/(Decrease) in Cash	(9,964)	3,019
Cash - Beginning of Year	12,773	8,021
Cash - End of Year	2,809	11,040
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	92,491	84,955
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	77,989	73,247
Deferred Income Tax Expense (Benefit)	42,563	67,827
Regulatory Over/(Under) Recoveries, Net	2,639	16,813
Amortization of Regulatory Assets/(Liabilities), Net	29,148	(17,565)
Proceeds from DOE Damages Claim		14,453
Other	10,894	10,834
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(25,126)	(7,467)
Increase Decrease in Fuel, Materials and Supplies	4,156	(17,350)
Taxes Receivable/(Accrued)	9,026	(24,108)
Accounts Payable	(20,058)	(9,297)
Other Current Assets and Liabilities, Net	20,141	13,470
Net Cash Flows Provided by Operating Activities	243,863	205,812
Investing Activities:
Investments in Property, Plant and Equipment	(209,522)	(170,127)
Other Investing Activities	241	(148)
Net Cash Flows Used in Investing Activities	(209,281)	(170,275)
Financing Activities:
Cash Dividends on Common Stock	(79,500)	(49,500)
Increase/(Decrease) in Notes Payable to Affiliate	46,800	66,800
Retirements of Long-Term Debt		(50,000)
Other Financing Activities	(268)	(217)
Net Cash Flows Provided by/(Used in) Financing Activities	(32,968)	(32,917)
Net Increase/(Decrease) in Cash	1,614	2,620
Cash - Beginning of Year	489	130
Cash - End of Year	2,103	2,750
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	42,410	39,785
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	32,420	31,144
Deferred Income Tax Expense (Benefit)	5,531	13,479
Regulatory Over/(Under) Recoveries, Net	4,024	33,630
Amortization of Regulatory Assets/(Liabilities), Net	11,194	(7,778)
Proceeds from DOE Damages Claim		18,883
Other	(4,500)	615
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(32,664)	36,075
Taxes Receivable/(Accrued)	24,064	(15,831)
Accounts Payable	(14,018)	(12,847)
Other Current Assets and Liabilities, Net	(463)	(16,551)
Net Cash Flows Provided by Operating Activities	67,998	120,604
Investing Activities:
Investments in Property, Plant and Equipment	(93,705)	(82,546)
Proceeds from Sales of Marketable Securities	71,110	58,788
Purchases of Marketable Securities	(71,625)	(59,280)
Net Cash Flows Used in Investing Activities	(94,220)	(83,038)
Financing Activities:
Cash Dividends on Common Stock	(27,900)	(49,000)
Increase/(Decrease) in Notes Payable to Affiliate	104,800	13,200
Retirements of Long-Term Debt	50,000
Other Financing Activities	(20)	(29)
Net Cash Flows Provided by/(Used in) Financing Activities	26,880	(35,829)
Net Increase/(Decrease) in Cash	658	1,737
Cash - Beginning of Year	0	0
Cash - End of Year	$ 658	$ 1,737

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Sep. 30, 2015
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 CONSOLIDATED 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 consolidated 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 . On April 30 , 2015, the Company's legal name was changed from Northeast Utilities to Eversource Energy. CL&P, NSTAR Electric, PSNH and WMECO are each doing business as Eversource Energy. 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 , the first and second quarter 2015 combine d Quarterly Report on Form 10 -Q and the 2014 combined Annual Report on Form 10 -K of Eversource , CL&P, NSTAR Electric, PS NH and WMECO, which were 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 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 September 30, 2015 and December 31, 2014, the results of operations and comprehensive income for the three and nine months ended September 30, 2015 and 2014 , and the cash flows for the nine months ended September 30, 2015 and 2014 . The results of operations and comprehensive income for the three and nine months ended September 30, 2015 and 2014 and the cash flows for the nine months ended September 30, 2015 and 2014 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. 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 . B. Accounting Standards Accou nting 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 , as a result of which ASU 2014-09 is required to be applied in the first quarter of 2018, with 2017 application permitted. The Company is reviewing the requirements of ASU 2014-09 and will implement the standard in the first quarter of 2018. The ASU is not expected to have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs , that changes the balance sheet presentation of debt issuance costs. Under the standard, issuance costs related to debt will be presented on the balance sheet as a direct deduction from the carrying amount of the debt liability rather than as a deferred cost as required by current guidance. The new accounting guidance is effective for interim and annual periods beginning in the first quarter of 2016 with early adoption permitted. Upon adoption, an entity must apply the new guidance retrospectively to all prior periods presented in the financial statements. The Company intends to adopt the new guidance at December 31, 2015. Management does not expect the adoption of this standard to have a material effect on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH or WMECO. 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 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 to also recover in rates amounts associated with certain uncollectible hardship accounts receivable. Uncollectible customer account balances, which are expected to be recovered in rates, are included in Regulatory Assets or Other Long-Term Assets. The total provision for uncollectible accounts and for uncollectible hardship accounts , which is included in the total provision, are included in Recei vables, Net on the balance sheets, and were as follows: Total Provision for Uncollectible Accounts Uncollectible Hardship (Millions of Dollars) As of September 30, 2015 As of December 31, 2014 As of September 30, 2015 As of December 31, 2014 Eversource $ 185.8 $ 175.3 $ 86.6 $ 91.5 CL&P 79.5 84.3 64.9 74.0 NSTAR Electric 46.4 40.7 - - PSNH 9.4 7.7 - - WMECO 13.2 9.9 7.7 6.2 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 status of pension and PBOP plans and nonrecurring fair value measurements of nonfinancial ass ets such as goodwill and AROs, and is also used to estimate the 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. 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 payments in Taxes Other Than I ncome Taxes on the statements of income as follows : For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 September 30, 2014 September 30, 2015 September 30, 2014 Eversource $ 37.8 $ 35.0 $ 112.9 $ 114.6 CL&P 35.5 32.5 98.0 99.0 Certain sales taxes are collected by Eversource 's companies that s erve customers in Connecticut and Massachusetts as agents for state and local governments and 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 September 30, 2015 As of September 30, 2014 Eversource $ 160.7 128.9 CL&P 46.0 52.2 NSTAR Electric 31.2 18.1 PSNH 33.8 21.0 WMECO 15.5 10.0 H. Severance Benefits E versource rec orded severance benefit expense of $ 1 million and $ 0. 7 million for the three months ended September 30 , 2015 and 2014 , respectively, and $ 2.6 million and $ 6.5 million for the nine months ended September 30 , 2015 and 2014, respectively, in connection with reorganizational and cost saving initiatives, and, in 2014, the partial outsourcing of information technology functions . As of September 30 , 2015 and December 31, 2014, the severance accrual totaled $ 7.1 million and $ 1 0. 4 million, respectively, and was included in Other Current Liabilities on the balance sheets. I. Income Taxes Income tax expense is estimated for each of the jurisdictions in which Eversource op erates and is recorded on the quarter using an estimated annualized effective tax rate. This process to record income tax expense involves estimating current and deferred income tax expense or benefit and the impact of temporary differences resulting from differing treatment of items for financial reporting and income tax return reporting purposes. Such differences are the result of timing of the deduction for expenses, as well as any impact of permanent differences, non-tax deductible expenses, or oth er items that directly impact the income tax return as a result of a regulatory activity (flow-through items). The temporary differences and flow-through items result in deferred tax assets and liabilities that are included in the balance sheets. Part of the annual process in making adjustments to these estimates is reconciling the provision for income taxes made during the income tax estimation process to what was filed in the income tax return (return to provision). In the third quarter of 2015, Eversource and CL&P recorded an $8 million and $4.2 million charge, respectively, as a result of reconciling and adjusting its 2014 provision for income taxes to what was filed on its 2014 income tax return. Concurrently, Eversource and CL&P recorded a reversal of state tax reserves in the third quarter of 2015, which resulted in a $5.9 million and $2.2 million benefit, respectively.

REGULATORY ACCOUNTING

REGULATORY ACCOUNTING	3 Months Ended
	Sep. 30, 2015
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 consider the effect of regulation o n the timing of the recognition of certain revenues and expenses . The Regulated companies' financial statements reflect the effects of the rate-making process. The ra tes 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 that 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 components of regulatory assets are as follows: As of September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Benefit Costs $ 1,941.8 $ 2,016.0 Derivative Liabilities 412.8 425.5 Income Taxes, Net 635.8 635.3 Storm Restoration Costs 461.3 502.8 Goodwill-related 490.0 505.4 Regulatory Tracker Mechanisms 373.1 350.5 Contractual Obligations - Yankee Companies 142.0 123.8 Other Regulatory Assets 148.9 167.3 Total Regulatory Assets 4,605.7 4,726.6 Less: Current Portion 653.9 672.5 Total Long-Term Regulatory Assets $ 3,951.8 $ 4,054.1 As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Benefit Costs $ 434.8 $ 486.8 $ 171.1 $ 84.2 $ 445.4 $ 515.9 $ 174.3 $ 85.0 Derivative Liabilities 406.9 1.4 - - 410.9 4.5 - - Income Taxes, Net 435.7 83.5 34.2 30.5 437.7 83.7 38.0 35.5 Storm Restoration Costs 286.5 113.5 36.3 25.0 319.6 103.7 47.7 31.8 Goodwill-related - 420.7 - - - 433.9 - - Regulatory Tracker Mechanisms 16.0 228.0 85.4 30.1 16.1 141.4 103.5 33.0 Other Regulatory Assets 84.4 69.6 34.9 12.7 66.1 94.7 41.3 12.9 Total Regulatory Assets 1,664.3 1,403.5 361.9 182.5 1,695.8 1,377.8 404.8 198.2 Less: Current Portion 243.3 223.5 89.5 48.8 220.3 198.7 111.7 51.9 Total Long-Term Regulatory Assets $ 1,421.0 $ 1,180.0 $ 272.4 $ 133.7 $ 1,475.5 $ 1,179.1 $ 293.1 $ 146.3 Regulatory Costs in Other Long-Term Assets : T he Regulated companies had $ 59.4 million ($ 2.4 million for CL&P , $ 21.1 million for NSTAR Electric , $ 3.2 million for PSNH and $ 16.2 million for WMECO) and $ 60.5 million ($ 1.3 million for CL&P, $ 33.2 million for NSTAR Electric , $0. 9 million for PSNH, and $ 11 million for WMECO) of additional regulatory costs as of September 30 , 2015 and December 31, 201 4 , 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 . The NSTAR Electric balance as of September 30 , 2015 and December 31, 2014 primarily related to costs deferred in connection with the basic ser vice bad debt adder. See below, within the "2015 Regulatory Developments" section of this footnote for further information. Regulatory Liabilities: The components of regulatory liabilities are as follows: As of September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Cost of Removal $ 433.7 $ 439.9 Regulatory Tracker Mechanisms 215.9 192.3 AFUDC - Transmission 66.2 67.1 Other Regulatory Liabilities 27.9 50.8 Total Regulatory Liabilities 743.7 750.1 Less: Current Portion 226.1 235.0 Total Long-Term Regulatory Liabilities $ 517.6 $ 515.1 As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Cost of Removal $ 17.2 $ 257.7 $ 49.1 $ 2.0 $ 19.7 $ 258.3 $ 50.3 $ 1.1 Regulatory Tracker Mechanisms 131.1 13.0 8.6 24.2 122.6 20.7 14.2 22.3 AFUDC - Transmission 51.8 5.4 - 9.0 53.6 4.4 - 9.1 Other Regulatory Liabilities 13.2 3.5 3.3 1.0 10.1 28.9 2.9 0.8 Total Regulatory Liabilities 213.3 279.6 61.0 36.2 206.0 312.3 67.4 33.3 Less: Current Portion 136.4 12.3 11.3 24.3 124.7 49.6 16.0 22.5 Total Long-Term Regulatory Liabilities $ 76.9 $ 267.3 $ 49.7 $ 11.9 $ 81.3 $ 262.7 $ 51.4 $ 10.8 2015 Regulatory Developments: FERC ROE Complaints: As a result of the March 3, 2015 FERC order in the pending ROE complaint proceedings described in Note 8 C, "Commitment s and Contingencies – FERC ROE Complaints , " in 2015, Eversource 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. NSTAR Electric and NSTAR Gas 2014 Comprehensive Settlement Agreement : On March 2, 2015, the DPU approved the comprehensive settlement agreement between NSTAR Electric, NSTAR Gas and the Massachusetts Attorney General (the " Settlement " ) as filed with the DPU on December 31, 2014. The Settlement resolved the outstanding NSTAR Electric CPSL program filings for 2006 through 2011, the NSTAR Electric and NSTAR Gas PAM and energy efficiency-related customer billing adjustments reported in 2012, and the recovery of LBR related to NSTAR Electric ' s energy efficiency programs for 2009 through 2011 (11 dockets in total). In 2015, as a result of the DPU order, NSTAR Electric and NSTAR Gas commenced refunding a combined $44.7 million to customers, which was recorded as a regulatory liability. NSTAR Electric recognized a $21.7 million p re-tax benefit in the first quarter of 2015 as a result of the approval of the Settlement . NSTAR Electric Basic Service Bad Debt Adder : On January 7, 2015, the DPU issued an order concluding that NSTAR Electric had removed energy-related bad debt costs from base distribution rates effective January 1, 2006. As a result of the DPU order, NSTAR Electric increased its regulatory assets and reduced operations and maintenance expense by $24.2 million in the first quarter of 2015 , resulting in after-tax earnings of $14.5 million. On May 5, 2015, NSTAR Electric filed for recovery of the energy-related bad debt costs regulatory asset from customers beginning July 1, 2015. On June 24, 2015, the DPU delayed the effective date of NSTAR Electric's proposed rate increase from July 1, 2015 to November 1, 2015 to allow for the DPU staff to review the reconciliations. NSTAR Electric requested recovery from customers effective January 1, 2016 in briefs filed with the DPU in October 2015. On October 27, 2015, the DPU delayed the effective date of the rate increase from November 1, 2015 to December 1, 2015 to allow the DPU staff additional time to review the reconciliations. NSTAR Electric expects a decision from the DPU in the fourth quarter of 2015. CL&P Distribution Rates : On July 2, 2015, PURA issued a final order that allows for an increase to rate base of approximately $16 3 million associated with ADIT, including a regulatory asset to recover the incremental revenue requirement for the period December 1, 2014 through November 30, 2015 over a subsequent two-year period. The rate base increase provided an increase to total allowed annual revenue requirements of $18.4 million beginning December 1, 2014. Of that amount, $15.3 million has been recorded as a regulatory asset through September 30, 2015, with a corresponding increase in Operating Revenues.

PROPERTY, PLANT AND ACCUMULATED

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION	3 Months Ended
	Sep. 30, 2015
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 September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Distribution - Electric $ 12,821.6 $ 12,495.2 Distribution - Natural Gas 2,657.5 2,595.4 Transmission 7,260.6 6,930.7 Generation 1,180.0 1,170.9 Electric and Natural Gas Utility 23,919.7 23,192.2 Other (1) 555.3 551.3 Property, Plant and Equipment, Gross 24,475.0 23,743.5 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,041.5) (5,777.8) Other (247.6) (231.8) Total Accumulated Depreciation (6,289.1) (6,009.6) Property, Plant and Equipment, Net 18,185.9 17,733.9 Construction Work in Progress 1,220.1 913.1 Total Property, Plant and Equipment, Net $ 19,406.0 $ 18,647.0 (1) These assets are primarily comprised of building improvements , computer software , hardware and equipment and telecommunications assets at Eversource S ervice and Eversource's unregulated companies . As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Distribution $ 5,289.6 $ 5,001.9 $ 1,772.0 $ 798.1 $ 5,158.8 $ 4,895.5 $ 1,696.7 $ 784.2 Transmission 3,480.5 1,995.3 839.9 896.7 3,274.0 1,928.5 789.7 891.0 Generation - - 1,145.5 34.5 - - 1,136.5 34.4 Property, Plant and Equipment, Gross 8,770.1 6,997.2 3,757.4 1,729.3 8,432.8 6,824.0 3,622.9 1,709.6 Less: Accumulated Depreciation (2,007.9) (1,857.9) (1,149.6) (302.6) (1,928.0) (1,761.4) (1,090.0) (297.4) Property, Plant and Equipment, Net 6,762.2 5,139.3 2,607.8 1,426.7 6,504.8 5,062.6 2,532.9 1,412.2 Construction Work in Progress 246.4 405.8 160.4 105.0 304.9 272.8 102.9 49.1 Total Property, Plant and Equipment, Net $ 7,008.6 $ 5,545.1 $ 2,768.2 $ 1,531.7 $ 6,809.7 $ 5,335.4 $ 2,635.8 $ 1,461.3 As of September 30, 2015, PSNH had $ 1.1 billion in gross generation utility plant assets and Accumulated Depreciation of $ 514 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, among other resolutions, PSNH has agreed to sell these generation assets. Upon completion of the sale, all remaining stranded costs will be recovered via bonds that will be secured by a non- bypassable charge on the bills of PSNH's customers . See Note 8 E , " Commitments and Contingencies – PSNH Generation Restructuring, " for further information.

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	9 Months Ended
	Sep. 30, 2015
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 customer s, 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 amount s 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 present s the gross fair values of contracts categorized by risk type and the net amount recorded as current or long-term derivative asset or liability: As of September 30, 2015 As of December 31, 2014 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 $ 16.6 $ (10.8) $ 5.8 $ 16.2 $ (6.6) $ 9.6 CL&P 16.6 (10.8) 5.8 16.1 (6.6) 9.5 NSTAR Electric - - - 0.1 - 0.1 Long-Term Derivative Assets: Level 3: Eversource $ 67.7 $ (22.2) $ 45.5 $ 93.5 $ (19.2) $ 74.3 CL&P 65.6 (22.2) 43.4 93.5 (19.2) 74.3 NSTAR Electric 2.1 - 2.1 - - - Current Derivative Liabilities: Level 2: Eversource $ (4.6) $ - $ (4.6) $ (9.8) $ - $ (9.8) Level 3: Eversource (92.6) - (92.6) (90.0) - (90.0) CL&P (91.4) - (91.4) (88.5) - (88.5) NSTAR Electric (1.2) - (1.2) (1.5) - (1.5) Long-Term Derivative Liabilities: Level 2: Eversource $ - $ - $ - $ (0.3) $ - $ (0.3) Level 3: Eversource (365.7) - (365.7) (409.3) - (409.3) CL&P (364.7) - (364.7) (406.2) - (406.2) NSTAR Electric (1.0) - (1.0) (3.1) - (3.1) (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 each contract allocated to CL&P and 20 percent 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 September 30, 2015 and December 31, 2014 , Eversource had NYMEX financial contracts for natural gas futures in order to reduce variability associated with the purchase price of approximately 9.9 million and 8.8 million MMBtu of natural gas, respectively. For the three months ended September 30 , 2015 and 2014, there were losses of $ 8.8 million and $ 15.7 million , respectively, deferred as regulatory costs , which reflect the current change in fair va lue associated with Eversource's derivative contracts . For the nine months ended September 30, 2015 and 2014, t here were losses of $ 58.9 million and gains of $ 149.9 million, respectively. 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 September 30 , 2015 and December 31, 201 4 , Eversource had approximately $ 4.6 million and $ 10 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 approximately $ 4.7 million and $ 10 million, respectively, if E versource parent ' 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 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 September 30, 2015 As of December 31, 2014 Range Period Covered Range Period Covered Capacity Prices: Eversource $ 10.30 - 13.13 per kW-Month 2016 - 2026 $ 5.30 - 12.98 per kW-Month 2016 - 2026 CL&P $ 10.81 - 12.60 per kW-Month 2019 - 2026 $ 11.08 - 12.98 per kW-Month 2018 - 2026 NSTAR Electric $ 10.30 - 13.13 per kW-Month 2016 - 2019 $ 5.30 - 11.10 per kW-Month 2016 - 2019 Forward Reserve: Eversource, CL&P $ 2.00 per kW-Month 2016 - 2024 $ 5.80 - 9.50 per kW-Month 2015 - 2024 REC Prices: Eversource, NSTAR Electric $ 45 - 50 per REC 2015 - 2018 $ 38 - 56 per REC 2015 - 2018 Exit price premiums of 6 percent through 23 percent are also applied on these contracts and reflect 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 liability. Any increases in the risk premiums would increase the fair value of the derivative liabilities. Changes in these fair values are recorded as a regulatory asset or liability and would 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 September 30, 2015 2014 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (422.4) $ (420.2) $ (2.2) $ (430.9) $ (424.6) $ (6.3) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (6.0) (7.6) 1.6 (13.6) (15.0) 1.4 Settlements 21.4 20.9 0.5 21.0 18.5 2.5 Fair Value as of End of Period $ (407.0) $ (406.9) $ (0.1) $ (423.5) $ (421.1) $ (2.4) For the Nine Months Ended September 30, 2015 2014 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (415.4) $ (410.9) $ (4.5) $ (635.2) $ (630.6) $ (7.3) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (55.3) (56.6) 1.3 147.6 149.4 0.9 Settlements 63.7 60.6 3.1 64.1 60.1 4.0 Fair Value as of End of Period $ (407.0) $ (406.9) $ (0.1) $ (423.5) $ (421.1) $ (2.4)

MARKETABLE SECURITIES

MARKETABLE SECURITIES	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Marketable Securities [Text Block]	5. MARKETABLE SECURITIES Eversource maintains trusts to fund certain non-qualified executive benefits and WMECO maintains a spent n uclear fuel trust to fund WMECO' s prior peri od spent nuclear fuel liability. These trusts hold marketable securities. These trusts are not subject to regulatory oversight by state or federal agencies. In addition, CYAPC and YAEC maintain legally restricted trusts, each of which holds marketable securities, for paying the decommissioning and 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 September 30 , 2015 and December 31, 2014 , these securities were classified as Leve l 1 in the fair value hierarchy and totaled $ 14.2 million and $85.1 million, respectively . N et losses on these securities of $ 0.5 million and $ 1.9 million for the three months ended September 30, 2015 and 2014 , respectively, and net gains of $ 1.6 million and $ 1.9 million, respectively , for the nine months ended September 30, 2015 and 2014, respectively , were recorded in Other Income, Net on the statements of income. Dividend income is recorded in Other Income, Net when dividends are declared. In 2015, certain of the securities classified as trading securities were sold and the proceeds were re-invested in equity securities designated as available-for-sale securities. Available-for-Sale Securities: The following is a summary of E versource ' s and WMECO' s available-for-sale securities. These securities are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of September 30, 2015 As of December 31, 2014 Pre-Tax Pre-Tax Pre-Tax Pre-Tax Amortized Unrealized Unrealized Amortized Unrealized Unrealized (Millions of Dollars) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Eversource Debt Securities (1) (2) $ 311.6 $ 3.6 $ (0.8) $ 314.4 $ 313.0 $ 7.5 $ (0.3) $ 320.2 Equity Securities (1) 220.0 53.9 (6.0) 267.9 160.6 73.3 - 233.9 WMECO Debt Securities (2) 58.3 - - 58.3 58.2 - (0.1) 58.1 A mounts include CYAPC's and YAEC's marketable securities held in nuclear decommissioning trusts of $ 430.2 million and $450.8 million as of September 30 , 2015 and December 31, 2014, respectively, which are legally restricted and can only be used for the costs of decommissioning and fuel removal of the nuclear fuel storage facilities owned by these companies. Unrealized gains and losses for the nuclear decommissioning trusts are recorded in Marketable S ecurities with the corresponding offset to Other Long-Term Liabilities on the balance sheets, with no impact on the statements of income. Unrealized gains and losses on debt securities held by WMECO are recorded in Marketable Securities with the corresponding offset to Other Long-Term Assets on the balance sheets. Unrealized Losses and Other-than-Temporary Impairment: There have been no significant unrealized losses, other-than-temporary imp airments or credit losses for Eversource or WMECO. 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, Other Long-Term Assets for WMECO, 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 WMECO trust and 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 September 30 , 2015, the contractual maturities of available-for-sale debt securities were as follows: Eversource WMECO Amortized Amortized (Millions of Dollars) Cost Fair Value Cost Fair Value Less than one year (1) $ 68.1 $ 68.1 $ 40.5 $ 40.5 One to five years 67.6 68.0 14.2 14.2 Six to ten years 56.9 56.9 0.5 0.5 Greater than ten years 119.0 121.4 3.1 3.1 Total Debt Securities $ 311.6 $ 314.4 $ 58.3 $ 58.3 1) Amou nts in the Less than one year E versource 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 WMECO (Millions of Dollars) As of September 30, 2015 As of December 31, 2014 As of September 30, 2015 As of December 31, 2014 Level 1: Mutual Funds and Equities $ 282.1 $ 319.0 $ - $ - Money Market Funds 30.7 24.9 8.0 4.3 Total Level 1 $ 312.8 $ 343.9 $ 8.0 $ 4.3 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 41.3 $ 51.3 $ - $ - Corporate Debt Securities 57.5 49.1 12.2 14.7 Asset-Backed Debt Securities 27.9 54.1 7.6 14.5 Municipal Bonds 123.9 116.3 10.3 13.0 Other Fixed Income Securities 33.1 24.5 20.2 11.6 Total Level 2 $ 283.7 $ 295.3 $ 50.3 $ 53.8 Total Marketable Securities $ 596.5 $ 639.2 $ 58.3 $ 58.1 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 AND LONG TERM DEBT

SHORT TERM AND LONG TERM DEBT	9 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Debt Disclosure	6. SHORT-TERM AND LONG-TERM DEBT Credit Agreements and Commercial Paper Programs : On October 26, 2015, Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas amended and restated their joint five-year $1.45 billion revolving credit facility and extended the termination date to September 4, 2020. The facility serves to backstop Eversource parent's $1.45 billion commercial paper program. The commercial paper program allows Eversource parent to issue commercial paper as a form of short-term debt. As of September 30, 2015 and December 31, 2014, Eversource parent had $ 757 million and approximately $1.1 billion, respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $ 693 million and $348.9 million of available borrowing capacity as of September 30, 2015 and December 31, 2014, respectively. The weighted-average interest rate on these borrowings as of September 30, 2015 and December 31, 2014 was 0.41 percent and 0.43 percent, respectively. As of September 30, 2015, there were intercompany loans from Eversource parent of $ 137.3 million to PSNH and $ 126 . 2 million to WMECO. As of December 31, 2014, there were intercompany loans from Eversource parent of $133.4 million to CL&P, $90.5 million to PSNH and $21.4 million to WMECO. On October 26, 2015, NSTAR Electric amended and restated its five-year $450 million revolving credit facility and extended the termination date to September 4, 2020. The facility serves to backstop NSTAR Electric's $450 million commercial paper program. As of September 30, 2015 and December 31, 2014, NSTAR Electric had $ 258.5 million and $302 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $ 191.5 million and $148 million of available borrowing capacity as of September 30, 2015 and December 31, 2014, respectively. The weighted-average interest rate on these borrowings as of September 30, 2015 and December 31, 2014 was 0.18 percent and 0.27 percent, respectively. On June 16, 2015, the FERC granted authorization to allow CL&P and WMECO to incur total short-term borrowings up to a maximum of $600 million and $300 million, respectively, effective January 1, 2016 through December 31, 2017. Except as described below, amounts outstanding under the commercial paper programs are included in Notes Payable for Eversource and NSTAR Electric and 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 E versource parent to CL&P, PSNH and WMECO ar e included in Notes Payable to Eversource Parent and classified in current liabilities on the balance sheets. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are eliminated in consolidation in Eversource 's balance sheets. Long-Term Debt: On January 15, 2015, Eversource parent issued $150 million of 1.60 percent Series G Senior Notes , due to mature in 2018 and $300 million of 3.15 percent Series H Senior Notes, due to mature in 2025. The proceeds, net of issuance costs, were used to repay short-term borrowings outstanding under the Eversource parent commercial paper program. As the debt issuances refinanced short-term debt, the short-term debt was classified as Long-Term Debt as of December 31, 2014. O n April 1, 2015, CL&P repaid at maturity the $100 million 5.00 percent 2005 Series A First and Refunding Mortgage Bonds using short-term borrowings. On April 1, 2015, CL&P also redeemed the $62 million 199 6 A Series 1.55 percent PCRB s that were subject to mandatory tender , using short term borrowings . On May 20, 2015, CL&P issued $300 million of 4.15 percent 2015 Series A First and Refunding Mortgage Bonds due to mature in 2045. The proceeds, net of issuance costs, were used to repay short-term borrowings. On August 3 , 2015, WMECO repaid at maturity the $50 million 5.24 percent Series C Senior Notes using short-term borrowings. On September 10, 2015, Yankee Gas issued $75 million of 3.35 percent 2015 Series M First Mortgage Bonds due to mature in 2025. The proceeds, net of issuance costs, were used to repay short-term borrowings. Long-Term Debt Issuance Authorization : On April 3 , 2015, the DPU authorized NSTAR Gas to issue up to $100 million in long-term debt for the period through December 31, 2015.

PENSION BENEFITS AND POSTRETIRE

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	7 . Pension Benefits and Postretirement Benefits Other than Pensions As of December 31, 2014, Eversource S ervice sponsored two defined benefit retirement plans that covered eligible employees, including employees of CL&P, NSTAR Electric, PSNH and WMECO . Effective January 1, 2015, the two pension plans were merg ed into one plan, sponsored by E versource S ervice . As of December 31, 2014, Eversource Se rvice also sponsored defined benefit postretirement plans that provide certain retiree benefits, primarily medical, dental and life insurance, to retiring employees that meet certain age and service eligibility requirements , including employees of CL&P, NSTAR Electric, PSNH and WMECO . Effective January 1, 2015, the postretirement plans were merged into one plan, sponsored by E versource S ervice . Terminated Vested Lump-Sum Payout Offer : In August, 2015, Eversource made a total lump-sum payout of $149.5 million, which reduced the projected benefit obligation and Pension Plan assets by a corresponding amount. Therefore, the lump-sum payment option had no impact on the net Accrued Pension Liability reflected on the Eversource, CL&P, PSNH and WMECO balance sheets as of September 30, 2015. 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 is included in Operations and Maintenance on the statements of income. Capitalized pension and PBOP amounts relate to employees working on capital projects and are included in Property, Plant and Equipment, Net. Intercompany allocations are not included in the CL&P, NSTAR Electric, PSNH and WMECO net periodic benefit expense amounts. 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 and the corresponding capitalized portion, as these amounts are cash settled on a short-term basis. Pension and SERP Pension and SERP Eversource For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 (1) September 30, 2014 September 30, 2015 (1) September 30, 2014 Service Cost $ 22.7 $ 19.1 $ 68.7 $ 60.7 Interest Cost 56.9 56.4 170.3 169.5 Expected Return on Plan Assets (83.9) (77.7) (252.1) (233.1) Actuarial Loss 36.5 31.7 111.9 96.5 Prior Service Cost 0.9 1.1 2.7 3.3 Total Net Periodic Benefit Expense $ 33.1 $ 30.6 $ 101.5 $ 96.9 Capitalized Pension Expense $ 9.8 $ 8.3 $ 31.3 $ 26.7 PBOP PBOP Eversource For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 (1) September 30, 2014 September 30, 2015 (1) September 30, 2014 Service Cost $ 4.1 $ 3.1 $ 10.3 $ 9.3 Interest Cost 11.8 12.4 30.4 37.1 Expected Return on Plan Assets (16.9) (15.8) (43.2) (47.4) Actuarial Loss 1.7 3.0 4.5 9.1 Prior Service Credit (0.1) (0.7) (0.3) (2.1) Total Net Periodic Benefit Expense $ 0.6 $ 2.0 $ 1.7 $ 6.0 Capitalized PBOP Expense/(Income) $ - $ 1.1 $ 0.1 $ 1.9 Pension and SERP For the Three Months Ended September 30, 2015 For the Three Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 6.2 $ 3.7 $ 3.1 $ 1.0 $ 5.0 $ 3.0 $ 2.3 $ 0.8 Interest Cost 12.9 10.0 6.1 2.6 12.5 10.3 5.7 2.5 Expected Return on Plan Assets (19.8) (17.5) (10.1) (4.7) (18.7) (15.7) (9.3) (4.4) Actuarial Loss 8.0 8.7 2.9 1.6 8.2 5.9 2.8 1.7 Prior Service Cost 0.4 - 0.1 0.1 0.4 - 0.1 0.1 Total Net Periodic Benefit Expense $ 7.7 $ 4.9 $ 2.1 $ 0.6 $ 7.4 $ 3.5 $ 1.6 $ 0.7 Intercompany Allocations $ 5.8 $ 3.4 $ 1.6 $ 1.1 $ 6.5 $ 2.9 $ 1.8 $ 1.2 Capitalized Pension Expense $ 4.7 $ 2.7 $ 0.8 $ 0.5 $ 4.3 $ 2.6 $ 0.7 $ 0.6 Pension and SERP For the Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 18.4 $ 11.2 $ 9.0 $ 3.2 $ 15.2 $ 10.6 $ 7.4 $ 2.7 Interest Cost 38.4 30.2 18.1 7.8 38.1 31.0 18.0 7.8 Expected Return on Plan Assets (59.1) (52.5) (30.3) (14.2) (56.7) (47.3) (28.8) (13.5) Actuarial Loss 24.2 27.0 8.8 4.8 25.5 17.6 8.9 5.2 Prior Service Cost 1.1 0.1 0.4 0.2 1.4 - 0.5 0.3 Total Net Periodic Benefit Expense $ 23.0 $ 16.0 $ 6.0 $ 1.8 $ 23.5 $ 11.9 $ 6.0 $ 2.5 Intercompany Allocations $ 18.0 $ 10.3 $ 5.0 $ 3.3 $ 20.8 $ 6.7 $ 6.0 $ 3.9 Capitalized Pension Expense $ 14.1 $ 8.6 $ 2.6 $ 1.4 $ 13.6 $ 5.5 $ 2.4 $ 2.0 PBOP For the Three Months Ended September 30, 2015 For the Three Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 0.5 $ 1.3 $ 0.3 $ 0.1 $ 0.6 $ 0.8 $ 0.3 $ 0.1 Interest Cost 1.8 4.8 1.0 0.3 2.0 4.9 1.1 0.4 Expected Return on Plan Assets (2.8) (6.8) (1.5) (0.6) (2.6) (6.5) (1.4) (0.6) Actuarial Loss/(Gain) 0.2 0.6 0.1 - 1.0 (0.1) 0.6 0.1 Prior Service Credit - (0.1) - - - (0.5) - - Total Net Periodic Benefit Expense/(Income) $ (0.3) $ (0.2) $ (0.1) $ (0.2) $ 1.0 $ (1.4) $ 0.6 $ 0.0 Intercompany Allocations $ 0.4 $ 0.2 $ 0.1 $ 0.1 $ 0.9 $ 0.3 $ 0.2 $ 0.2 Capitalized PBOP Expense/(Income) $ (0.1) $ - $ 0.1 $ - $ 0.5 $ (0.5) $ 0.2 $ - PBOP For the Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 1.6 $ 4.0 $ 1.0 $ 0.3 $ 1.7 $ 2.3 $ 1.0 $ 0.3 Interest Cost 5.4 14.2 2.9 1.1 6.0 14.6 3.2 1.3 Expected Return on Plan Assets (8.3) (20.5) (4.4) (1.9) (7.9) (19.5) (4.1) (1.7) Actuarial Loss/(Gain) 0.5 1.8 0.4 - 3.2 (0.4) 1.7 0.3 Prior Service Credit - (0.1) - - - (1.4) - - Total Net Periodic Benefit Expense/(Income) $ (0.8) $ (0.6) $ (0.1) $ (0.5) $ 3.0 $ (4.4) $ 1.8 $ 0.2 Intercompany Allocations $ 1.4 $ 0.7 $ 0.3 $ 0.3 $ 3.1 $ 0.4 $ 0.8 $ 0.6 Capitalized PBOP Expense/(Income) $ (0.2) $ (0.1) $ 0.2 $ (0.1) $ 1.5 $ (1.5) $ 0.6 $ 0.1 (1) Amounts exclude approximately $0.8 million and $2.4 million for the three and nine months ended September 30, 2015, respectively, that represented amounts included in other deferred debits.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Commitments and Contingencies Disclosure [Text Block]	8 . COMMITMENTS AND CONTINGENCIES A. Environmental Matters General: 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 believe that they are substantially in compliance with all enacted laws and regulations. The number of environmental sites and reserves related to these sites for which remediation or long-term monitoring, preliminary site work or site assessment are being performed are as follows : As of September 30, 2015 As of December 31, 2014 Reserve Reserve Number of Sites (in millions) Number of Sites (in millions) Eversource 64 $ 46.9 65 $ 43.3 CL&P 14 4.8 16 3.8 NSTAR Electric 14 2.2 13 1.1 PSNH 12 3.4 13 5.2 WMECO 4 0.6 4 0.5 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. The reserve balance related to these former MGP sites was $ 41 mi llion and $ 38.8 million as of September 30 , 2015 and December 31, 201 4 , respectively, and relates primarily to the natural gas business segment. These 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, CL&P, NSTAR Electric, PSNH, or WMECO's responsibility or the extent of remediation required, recently enacted laws and regulations or a change in the estimates due to certain economic factors. B . Guarantees and Indemnifications E versource parent provides credit assurances on behalf of its subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, in the form of guarantees in the normal course of business. 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 not exceed $206 million and will decrease as capital contributions are made . The guaranty will expire upon the earlier of the full performance of the guaranteed obligations or December 31, 2021. E versource 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, E versource parent will guarantee the financial obligations of NPT under the TSA in an amount not to exceed $25 million. E versource parent 's obligations under the guaranty expire upon the full, final and indefeasible payment of the guaranteed obligations. Eversource p arent has provided a guar anty of various indemnification and other obligations as a result of the April 13 , 2015 sale of substantially all of the assets of E.S. Boulos Company, an unregulated electrical contractor based in Maine and indirect subsidiary of Eversource Energy . E versource parent has also guarantee d 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 a ntic ipate a material impact to Net Income as a result of these various guarantees and indemnifications. T he following table summarizes E versource parent 's exposure to guarantees and indemnifications of its subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, and guarantees to external parties, as of September 30, 2015 : Maximum Exposure Company Description (in millions) Expiration Dates On behalf of subsidiaries: Various Surety Bonds (1) $ 33.2 2015 - 2016 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate $ 12.2 2019 and 2024 On behalf of external parties: Purchaser of E.S. Boulos Company and a bonding company E.S. Boulos Company Indemnification $ 38.2 2016 and 2020 Algonquin Gas Transmission, LLC Access Northeast project (owner of Access Northeast assets) capital contributions guarantee $ 206.0 2021 (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 . FERC ROE Complaints T hree 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 the first complaint, filed in 2011, the Complainants alleged that the NETOs' base ROE of 11.14 percent that had been utilized since 2006 was unjust and unreasonable, asserted that the rate was excessive due to changes in the capital markets, and sought an order to reduce it prospectively from the date of the final FERC order and for the 15-month period beginning October 1, 2011 to December 31, 2012 (the "first complaint refund period"). In the second and third complaints, filed in 2012 and 2014, the Complainants challenged the NETOs' base ROE and sought refunds for the respective 15-month periods beginning December 27, 2012 and July 31, 2014. In 2014, the FERC determined that the base ROE should be set at 10.57 percent for the first complaint refund period and that a utility's total or maximum ROE should not exceed the top of the new zone of reasonableness, which was set at 11.74 percent. The FERC ordered the NETOs to provide refunds to customers for the first complaint refund period and set the new base ROE of 10.57 percent prospectively from October 16, 2014. The NETOs and the Complainants sought rehearing from FERC. In late 2014, the NETOs made a compliance filing, which was challenged by the Complainants, and the Company began refunding amounts from the first complaint period. On March 3, 2015, FERC issued an order denying all issues raised on rehearing by the NETOs and Co mplainants in the first complaint. The FERC order upheld the base ROE of 10.57 percent for the first complaint refund period and prospectively from October 16, 2014, and upheld that the utility's total ROE (the base ROE plus any incentive adders) for the transmission assets to which the adder applies is capped at the top of the zone of reasonableness, which is currently set at 11.74 percent . As a result of the clarifying information in the March 2015 order related to the application of the ROE cap, Eversource adjusted its reserve 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 to the D.C. Circuit Court of Appeals, which have been consolidated, and briefing is scheduled to be concluded in the second quarter of 2016. A court decision is not expected until the second half of 2016. For the second and third complaint proceedings, hearings were held in late June and early July 2015 and briefs were filed in July and August 2015. The state parties, municipal utilities and FERC trial staff each believe that the base ROE should be reduced . T he NETOs believe that the Complainants' positions are without merit, and the existing ROEs should be maintained. The FERC ALJ's initial recommendation is expected by December 30, 2015, and a final FERC order is expected in the third quarter of 2016. D . NSTAR Electric Basic Service Bad Debt Adder On January 7, 2015, the DPU issued an order concluding that NSTAR Electric had removed energy-related bad debt costs from base distribution rates effective January 1, 2006. As a result of the DPU order, NSTAR Electric increased its regulatory assets and reduced operations and maintenance expense by $24.2 million in the first quarter of 2015 , resulting in after-tax earnings of $14.5 million. On May 5, 2015, NSTAR Electric filed for recovery of the energy-related bad debt costs regulatory asset from customers beginning July 1, 2015. On June 24, 2015, the DPU delayed the effective date of NSTAR Electric's proposed rate increase from July 1, 2015 to November 1, 2015 to allow for the DPU staff to review the reconciliations. NSTAR Electric requested recovery from customers effective January 1, 2016 in briefs filed with the DPU in October 2015. On October 27, 2015, the DPU delayed the effective date of the rate increase from November 1, 2015 to December 1, 2015 to allow the DPU staff additional time to review the reconciliations . NSTAR Electric expects a decision from the DPU in the fourth quarter of 2015. 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 Staff of the NHPUC, 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 has 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. When implemented, the Agreement provides 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 has 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 the second quarter of 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, including any remaining deferred equity return in excess of the $25 million that PSNH has agreed to forego, will be recovered via bonds that will be secured by a non- bypassable charge in rates billed to PSNH's customers. Implementation of the Agreement is subject to NHPUC approval, which is expected in early 2016.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	3 Months Ended
	Sep. 30, 2015
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 September 30, 2015 As of December 31, 2014 Eversource Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 157.3 $ 155.6 $ 153.6 Long-Term Debt 8,986.4 9,419.6 8,851.6 9,451.2 As of September 30, 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 $ 115.4 $ 43.0 $ 41.9 $ - $ - $ - $ - Long-Term Debt 2,975.3 3,285.1 1,792.7 1,931.3 1,076.3 1,135.5 577.8 613.3 As of December 31, 2014 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 $ 112.0 $ 43.0 $ 41.6 $ - $ - $ - $ - Long-Term Debt 2,842.0 3,214.5 1,797.4 1,993.5 1,076.3 1,137.9 628.5 689.4 Derivative Instruments: D erivative instruments are carried at fair value. For further information, see Note 4 , "Derivative Instruments," to the financial statements. Other Financial Instruments: Investments in marketable secur ities are carried at fair value. For further information, see Note 5 , "Marketable Securities," to the financial statements. The carrying value of other financial instruments included in current assets and current liabilities, including cash and cash equivalents and special deposits, approximates their fair value due to the short-term nature of these instruments . 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
	Sep. 30, 2015
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 Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 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 $ (12.4) $ 0.7 $ (62.3) $ (74.0) $ (14.4) $ 0.4 $ (32.0) $ (46.0) OCI Before Reclassifications - (3.9) (0.4) (4.3) - 0.2 1.2 1.4 Amounts Reclassified from AOCI 1.5 - 3.3 4.8 1.5 - 2.9 4.4 Net OCI 1.5 (3.9) 2.9 0.5 1.5 0.2 4.1 5.8 Balance as of End of Period $ (10.9) $ (3.2) $ (59.4) $ (73.5) $ (12.9) $ 0.6 $ (27.9) $ (40.2) 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, which 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 over the average future employee service period, and is reflected in amounts reclassified from AOCI. The related tax effects of the reclassification adjustments are not material to the financial statements for the nine months ended September 30 , 2015 and 2014.

COMMON SHARES

COMMON SHARES	3 Months Ended
	Sep. 30, 2015
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 the shares of common stock of CL&P, NSTAR Electric , PSNH and WMECO that were authorized and issued and the respective per share par values : Shares Authorized as of Per Share September 30, 2015 and Issued as of Par Value December 31, 2014 September 30, 2015 December 31, 2014 Eversource $ 5 380,000,000 333,862,615 333,359,172 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 September 30 , 2015 and December 31, 2014 , there were 16,671,366 and 16,375,835 E versource common shares held as treasury shares, respectively. As of September 30 , 2015 and December 31, 2014 , Eversource common sha res outstanding were 317,191,249 and 316 , 983 , 337 , respectively. In May 2015, the Company repurchased 532,521 treasury shares at a share price of $47. 94.

COMMON SHARESHOLDERS' EQUITY AN

COMMON SHARESHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (NU)	3 Months Ended
	Sep. 30, 2015
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 September 30, 2015 and 2014 and $5.6 million for the nine months ended September 30, 2015 and 2014. These dividends w ere presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. 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
	Sep. 30, 2015
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 . For the three an d nine months ended September 30 , 2015, there were 5,894 and 1,965 antidilutive share awards excluded from the computation, respectively. For the three and nine months ended September 30 , 201 4 , t here 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 For the Nine Months Ended (Millions of Dollars, except share information) September 30, 2015 September 30, 2014 September 30, 2015 September 30, 2014 Net Income Attributable to Common Shareholders $ 235.9 $ 234.6 $ 696.7 $ 597.9 Weighted Average Common Shares Outstanding: Basic 317,452,212 316,340,691 317,296,107 315,941,904 Dilutive Effect 953,057 1,214,234 1,099,935 1,244,586 Diluted 318,405,269 317,554,925 318,396,042 317,186,490 Basic EPS $ 0.74 $ 0.74 $ 2.20 $ 1.89 Diluted EPS $ 0.74 $ 0.74 $ 2.19 $ 1.89 RSUs and performance shares are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. The dilutive effect of unvested RSUs and performance shares is calculated using the treasury stock method. Assumed proceeds of the se units under the treasury stock method consist of the remaining compensation cost to be recognized and a theoretical tax benefit. The theoretical tax benefit is calculated as the tax impact of the intrinsic value of the units (the difference between the market value of the average units outstanding for the period, using the average market price during the period, and the grant date market value). The dilutive effect of stock options to purchase common shares is also calculated using the treasury stock method. Assumed proceeds for stock options consist of cash proceeds that would be received upon exercise, and a theoretical tax benefit. The theoretical tax benefit is calculated as the tax impact of the intrinsic value of the stock options (the difference between the market value of the average stock options outstanding for the period, using the average market price during the period, and the exercise price).

SEGMENT INFORMATION

SEGMENT INFORMATION	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Segment Reporting Disclosure [Text Block]	14 . SEGMENT INFORMATION Presentation: Eversource is organized between 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 i nformation is as follows : For the Three Months Ended September 30, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,543.7 $ 106.2 $ 270.4 $ 211.6 $ (198.8) $ 1,933.1 Depreciation and Amortization (84.5) (17.5) (42.4) (7.1) 0.5 (151.0) Other Operating Expenses (1,140.8) (92.7) (78.3) (199.6) 198.5 (1,312.9) Operating Income 318.4 (4.0) 149.7 4.9 0.2 469.2 Interest Expense (47.4) (9.2) (25.9) (11.2) 1.2 (92.5) Other Income, Net 1.9 (0.2) 3.8 241.9 (242.2) 5.2 Net Income Attributable to Common Shareholders $ 167.5 $ (3.7) $ 78.0 $ 234.9 $ (240.8) $ 235.9 For the Nine Months Ended September 30, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 4,686.5 $ 799.6 $ 787.2 $ 655.2 $ (664.9) $ 6,263.6 Depreciation and Amortization (342.1) (53.4) (122.6) (21.5) 1.6 (538.0) Other Operating Expenses (3,535.7) (631.5) (225.5) (619.4) 665.2 (4,346.9) Operating Income 808.7 114.7 439.1 14.3 1.9 1,378.7 Interest Expense (140.6) (27.2) (79.8) (35.4) 3.4 (279.6) Other Income, Net 9.6 (0.1) 11.9 777.0 (774.5) 23.9 Net Income Attributable to Common Shareholders $ 418.9 $ 57.3 $ 225.0 $ 764.7 $ (769.2) $ 696.7 Cash Flows Used for Investments in Plant $ 506.5 $ 120.0 $ 493.9 $ 56.9 $ - $ 1,177.3 For the Three Months Ended September 30, 2014 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,502.6 $ 109.2 $ 262.5 $ 211.2 $ (193.0) $ 1,892.5 Depreciation and Amortization (71.7) (16.4) (37.4) (13.8) 8.6 (130.7) Other Operating Expenses (1,141.5) (98.4) (74.2) (192.4) 185.6 (1,320.9) Operating Income/(Loss) 289.4 (5.6) 150.9 5.0 1.2 440.9 Interest Expense (49.2) (8.5) (24.5) (8.6) 1.0 (89.8) Other Income, Net 9.3 0.1 2.7 226.4 (226.6) 11.9 Net Income/Loss) Attributable to Common Shareholders $ 153.4 $ (9.9) $ 88.1 $ 228.3 $ (225.3) $ 234.6 For the Nine Months Ended September 30, 2014 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 4,350.4 $ 737.5 $ 721.4 $ 568.1 $ (516.7) $ 5,860.7 Depreciation and Amortization (309.9) (51.1) (111.4) (28.3) 12.7 (488.0) Other Operating Expenses (3,343.9) (586.2) (211.5) (534.1) 505.6 (4,170.1) Operating Income 696.6 100.2 398.5 5.7 1.6 1,202.6 Interest Expense (143.8) (25.6) (78.8) (27.2) 3.2 (272.2) Other Income, Net 13.6 0.2 6.9 657.9 (659.5) 19.1 Net Income Attributable to Common Shareholders $ 349.1 $ 44.2 $ 206.8 $ 653.4 $ (655.6) $ 597.9 Cash Flows Used for Investments in Plant $ 480.1 $ 120.6 $ 469.9 $ 46.9 $ - $ 1,117.5 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 September 30, 2015 $ 17,836.8 $ 2,986.0 $ 7,773.7 $ 12,750.0 $ (11,300.5) $ 30,046.0 As of December 31, 2014 17,563.4 3,030.9 7,625.6 12,682.5 (11,124.4) 29,778.0

SIGNIFCANT ACCOUNTING POLICIES

SIGNIFCANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Sep. 30, 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 . On April 30 , 2015, the Company's legal name was changed from Northeast Utilities to Eversource Energy. CL&P, NSTAR Electric, PSNH and WMECO are each doing business as Eversource Energy. 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 , the first and second quarter 2015 combine d Quarterly Report on Form 10 -Q and the 2014 combined Annual Report on Form 10 -K of Eversource , CL&P, NSTAR Electric, PS NH and WMECO, which were 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 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 September 30, 2015 and December 31, 2014, the results of operations and comprehensive income for the three and nine months ended September 30, 2015 and 2014 , and the cash flows for the nine months ended September 30, 2015 and 2014 . The results of operations and comprehensive income for the three and nine months ended September 30, 2015 and 2014 and the cash flows for the nine months ended September 30, 2015 and 2014 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. 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 .
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 accounts are terminated and these balances are deemed to be uncollectible.
Derivatives Offsetting Fair Value Amounts Policy	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.
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 status of pension and PBOP plans and nonrecurring fair value measurements of nonfinancial ass ets such as goodwill and AROs, and is also used to estimate the 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 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 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 payments in Taxes Other Than Income Taxes on the statements of income Certain sales taxes are collected by Eversource's companies that serve customers in Connecticut and Massachusetts as agents for state and local governments and 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 consider the effect of regulation o n the timing of the recognition of certain revenues and expenses . The Regulated companies' financial statements reflect the effects of the rate-making process. The ra tes 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 that 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.
Derivatives Policy Text Block	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 amount s are recovered from, or refunded to, customers in their respective energy supply rates.
Marketable Securities Policy	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.
Environmental Costs Policy	Environmental Matters General: 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 believe that they are 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 . RSUs and performance shares are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. The dilutive effect of unvested RSUs and performance shares is calculated using the treasury stock method. Assumed proceeds of the se units under the treasury stock method consist of the remaining compensation cost to be recognized and a theoretical tax benefit. The theoretical tax benefit is calculated as the tax impact of the intrinsic value of the units (the difference between the market value of the average units outstanding for the period, using the average market price during the period, and the grant date market value). The dilutive effect of stock options to purchase common shares is also calculated using the treasury stock method. Assumed proceeds for stock options consist of cash proceeds that would be received upon exercise, and a theoretical tax benefit. The theoretical tax benefit is calculated as the tax impact of the intrinsic value of the stock options (the difference between the market value of the average stock options outstanding for the period, using the average market price during the period, and the exercise price).
Segment Reporting Policy Policy Text Block	SEGMENT INFORMATION Presentation: Eversource is organized between 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
	Sep. 30, 2015
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 September 30, 2015 As of December 31, 2014 As of September 30, 2015 As of December 31, 2014 Eversource $ 185.8 $ 175.3 $ 86.6 $ 91.5 CL&P 79.5 84.3 64.9 74.0 NSTAR Electric 46.4 40.7 - - PSNH 9.4 7.7 - - WMECO 13.2 9.9 7.7 6.2

Other Taxes (Tables)

Other Taxes (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
State Of Connecticut Gross Earnings Taxes [Table Text Block]	For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 September 30, 2014 September 30, 2015 September 30, 2014 Eversource $ 37.8 $ 35.0 $ 112.9 $ 114.6 CL&P 35.5 32.5 98.0 99.0

Supplemental Cash Flow Informat

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Sep. 30, 2015
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 September 30, 2015 As of September 30, 2014 Eversource $ 160.7 128.9 CL&P 46.0 52.2 NSTAR Electric 31.2 18.1 PSNH 33.8 21.0 WMECO 15.5 10.0

REGULATORY ACCOUNTING (Tables)

REGULATORY ACCOUNTING (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Regulatory Assets Text Block	As of September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Benefit Costs $ 1,941.8 $ 2,016.0 Derivative Liabilities 412.8 425.5 Income Taxes, Net 635.8 635.3 Storm Restoration Costs 461.3 502.8 Goodwill-related 490.0 505.4 Regulatory Tracker Mechanisms 373.1 350.5 Contractual Obligations - Yankee Companies 142.0 123.8 Other Regulatory Assets 148.9 167.3 Total Regulatory Assets 4,605.7 4,726.6 Less: Current Portion 653.9 672.5 Total Long-Term Regulatory Assets $ 3,951.8 $ 4,054.1 As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Benefit Costs $ 434.8 $ 486.8 $ 171.1 $ 84.2 $ 445.4 $ 515.9 $ 174.3 $ 85.0 Derivative Liabilities 406.9 1.4 - - 410.9 4.5 - - Income Taxes, Net 435.7 83.5 34.2 30.5 437.7 83.7 38.0 35.5 Storm Restoration Costs 286.5 113.5 36.3 25.0 319.6 103.7 47.7 31.8 Goodwill-related - 420.7 - - - 433.9 - - Regulatory Tracker Mechanisms 16.0 228.0 85.4 30.1 16.1 141.4 103.5 33.0 Other Regulatory Assets 84.4 69.6 34.9 12.7 66.1 94.7 41.3 12.9 Total Regulatory Assets 1,664.3 1,403.5 361.9 182.5 1,695.8 1,377.8 404.8 198.2 Less: Current Portion 243.3 223.5 89.5 48.8 220.3 198.7 111.7 51.9 Total Long-Term Regulatory Assets $ 1,421.0 $ 1,180.0 $ 272.4 $ 133.7 $ 1,475.5 $ 1,179.1 $ 293.1 $ 146.3
Schedule Of Regulatory Liabilities Text Block	As of September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Cost of Removal $ 433.7 $ 439.9 Regulatory Tracker Mechanisms 215.9 192.3 AFUDC - Transmission 66.2 67.1 Other Regulatory Liabilities 27.9 50.8 Total Regulatory Liabilities 743.7 750.1 Less: Current Portion 226.1 235.0 Total Long-Term Regulatory Liabilities $ 517.6 $ 515.1 As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Cost of Removal $ 17.2 $ 257.7 $ 49.1 $ 2.0 $ 19.7 $ 258.3 $ 50.3 $ 1.1 Regulatory Tracker Mechanisms 131.1 13.0 8.6 24.2 122.6 20.7 14.2 22.3 AFUDC - Transmission 51.8 5.4 - 9.0 53.6 4.4 - 9.1 Other Regulatory Liabilities 13.2 3.5 3.3 1.0 10.1 28.9 2.9 0.8 Total Regulatory Liabilities 213.3 279.6 61.0 36.2 206.0 312.3 67.4 33.3 Less: Current Portion 136.4 12.3 11.3 24.3 124.7 49.6 16.0 22.5 Total Long-Term Regulatory Liabilities $ 76.9 $ 267.3 $ 49.7 $ 11.9 $ 81.3 $ 262.7 $ 51.4 $ 10.8

PROPERTY, PLANT AND ACCUMULAT25

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule of Public Utility Property, Plant, and Equipment [Text Block]	As of September 30, 2015 As of December 31, 2014 (Millions of Dollars) Eversource Eversource Distribution - Electric $ 12,821.6 $ 12,495.2 Distribution - Natural Gas 2,657.5 2,595.4 Transmission 7,260.6 6,930.7 Generation 1,180.0 1,170.9 Electric and Natural Gas Utility 23,919.7 23,192.2 Other (1) 555.3 551.3 Property, Plant and Equipment, Gross 24,475.0 23,743.5 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,041.5) (5,777.8) Other (247.6) (231.8) Total Accumulated Depreciation (6,289.1) (6,009.6) Property, Plant and Equipment, Net 18,185.9 17,733.9 Construction Work in Progress 1,220.1 913.1 Total Property, Plant and Equipment, Net $ 19,406.0 $ 18,647.0 As of September 30, 2015 As of December 31, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH WMECO CL&P Electric PSNH WMECO Distribution $ 5,289.6 $ 5,001.9 $ 1,772.0 $ 798.1 $ 5,158.8 $ 4,895.5 $ 1,696.7 $ 784.2 Transmission 3,480.5 1,995.3 839.9 896.7 3,274.0 1,928.5 789.7 891.0 Generation - - 1,145.5 34.5 - - 1,136.5 34.4 Property, Plant and Equipment, Gross 8,770.1 6,997.2 3,757.4 1,729.3 8,432.8 6,824.0 3,622.9 1,709.6 Less: Accumulated Depreciation (2,007.9) (1,857.9) (1,149.6) (302.6) (1,928.0) (1,761.4) (1,090.0) (297.4) Property, Plant and Equipment, Net 6,762.2 5,139.3 2,607.8 1,426.7 6,504.8 5,062.6 2,532.9 1,412.2 Construction Work in Progress 246.4 405.8 160.4 105.0 304.9 272.8 102.9 49.1 Total Property, Plant and Equipment, Net $ 7,008.6 $ 5,545.1 $ 2,768.2 $ 1,531.7 $ 6,809.7 $ 5,335.4 $ 2,635.8 $ 1,461.3

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value Text Block	As of September 30, 2015 As of December 31, 2014 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 $ 16.6 $ (10.8) $ 5.8 $ 16.2 $ (6.6) $ 9.6 CL&P 16.6 (10.8) 5.8 16.1 (6.6) 9.5 NSTAR Electric - - - 0.1 - 0.1 Long-Term Derivative Assets: Level 3: Eversource $ 67.7 $ (22.2) $ 45.5 $ 93.5 $ (19.2) $ 74.3 CL&P 65.6 (22.2) 43.4 93.5 (19.2) 74.3 NSTAR Electric 2.1 - 2.1 - - - Current Derivative Liabilities: Level 2: Eversource $ (4.6) $ - $ (4.6) $ (9.8) $ - $ (9.8) Level 3: Eversource (92.6) - (92.6) (90.0) - (90.0) CL&P (91.4) - (91.4) (88.5) - (88.5) NSTAR Electric (1.2) - (1.2) (1.5) - (1.5) Long-Term Derivative Liabilities: Level 2: Eversource $ - $ - $ - $ (0.3) $ - $ (0.3) Level 3: Eversource (365.7) - (365.7) (409.3) - (409.3) CL&P (364.7) - (364.7) (406.2) - (406.2) NSTAR Electric (1.0) - (1.0) (3.1) - (3.1)
Rollforward Of Net Derivative Asset Liabilities Valued Using Unobservable Inputs [Table Text Block]	For the Three Months Ended September 30, 2015 2014 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (422.4) $ (420.2) $ (2.2) $ (430.9) $ (424.6) $ (6.3) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (6.0) (7.6) 1.6 (13.6) (15.0) 1.4 Settlements 21.4 20.9 0.5 21.0 18.5 2.5 Fair Value as of End of Period $ (407.0) $ (406.9) $ (0.1) $ (423.5) $ (421.1) $ (2.4) For the Nine Months Ended September 30, 2015 2014 NSTAR NSTAR (Millions of Dollars) Eversource CL&P Electric Eversource CL&P Electric Derivatives, Net: Fair Value as of Beginning of Period $ (415.4) $ (410.9) $ (4.5) $ (635.2) $ (630.6) $ (7.3) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (55.3) (56.6) 1.3 147.6 149.4 0.9 Settlements 63.7 60.6 3.1 64.1 60.1 4.0 Fair Value as of End of Period $ (407.0) $ (406.9) $ (0.1) $ (423.5) $ (421.1) $ (2.4)
Fairvalueinputsliabilitiesquantitativeinformationtabletextblock	As of September 30, 2015 As of December 31, 2014 Range Period Covered Range Period Covered Capacity Prices: Eversource $ 10.30 - 13.13 per kW-Month 2016 - 2026 $ 5.30 - 12.98 per kW-Month 2016 - 2026 CL&P $ 10.81 - 12.60 per kW-Month 2019 - 2026 $ 11.08 - 12.98 per kW-Month 2018 - 2026 NSTAR Electric $ 10.30 - 13.13 per kW-Month 2016 - 2019 $ 5.30 - 11.10 per kW-Month 2016 - 2019 Forward Reserve: Eversource, CL&P $ 2.00 per kW-Month 2016 - 2024 $ 5.80 - 9.50 per kW-Month 2015 - 2024 REC Prices: Eversource, NSTAR Electric $ 45 - 50 per REC 2015 - 2018 $ 38 - 56 per REC 2015 - 2018

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Available For Sale Securities Reconciliation [Table TextBlock]	As of September 30, 2015 As of December 31, 2014 Pre-Tax Pre-Tax Pre-Tax Pre-Tax Amortized Unrealized Unrealized Amortized Unrealized Unrealized (Millions of Dollars) Cost Gains Losses Fair Value Cost Gains Losses Fair Value Eversource Debt Securities (1) (2) $ 311.6 $ 3.6 $ (0.8) $ 314.4 $ 313.0 $ 7.5 $ (0.3) $ 320.2 Equity Securities (1) 220.0 53.9 (6.0) 267.9 160.6 73.3 - 233.9 WMECO Debt Securities (2) 58.3 - - 58.3 58.2 - (0.1) 58.1
Investments Classified by Contractual Maturity Date [Table Text Block]	Eversource WMECO Amortized Amortized (Millions of Dollars) Cost Fair Value Cost Fair Value Less than one year (1) $ 68.1 $ 68.1 $ 40.5 $ 40.5 One to five years 67.6 68.0 14.2 14.2 Six to ten years 56.9 56.9 0.5 0.5 Greater than ten years 119.0 121.4 3.1 3.1 Total Debt Securities $ 311.6 $ 314.4 $ 58.3 $ 58.3
Fair Value Heirarchy [Table Text Block]	Eversource WMECO (Millions of Dollars) As of September 30, 2015 As of December 31, 2014 As of September 30, 2015 As of December 31, 2014 Level 1: Mutual Funds and Equities $ 282.1 $ 319.0 $ - $ - Money Market Funds 30.7 24.9 8.0 4.3 Total Level 1 $ 312.8 $ 343.9 $ 8.0 $ 4.3 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 41.3 $ 51.3 $ - $ - Corporate Debt Securities 57.5 49.1 12.2 14.7 Asset-Backed Debt Securities 27.9 54.1 7.6 14.5 Municipal Bonds 123.9 116.3 10.3 13.0 Other Fixed Income Securities 33.1 24.5 20.2 11.6 Total Level 2 $ 283.7 $ 295.3 $ 50.3 $ 53.8 Total Marketable Securities $ 596.5 $ 639.2 $ 58.3 $ 58.1

Pension Benefits and Postreti28

Pension Benefits and Postretirement Benefits Other Than Pensions (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Net Benefit Costs [Table Text Block]	Pension and SERP Pension and SERP Eversource For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 (1) September 30, 2014 September 30, 2015 (1) September 30, 2014 Service Cost $ 22.7 $ 19.1 $ 68.7 $ 60.7 Interest Cost 56.9 56.4 170.3 169.5 Expected Return on Plan Assets (83.9) (77.7) (252.1) (233.1) Actuarial Loss 36.5 31.7 111.9 96.5 Prior Service Cost 0.9 1.1 2.7 3.3 Total Net Periodic Benefit Expense $ 33.1 $ 30.6 $ 101.5 $ 96.9 Capitalized Pension Expense $ 9.8 $ 8.3 $ 31.3 $ 26.7 PBOP PBOP Eversource For the Three Months Ended For the Nine Months Ended (Millions of Dollars) September 30, 2015 (1) September 30, 2014 September 30, 2015 (1) September 30, 2014 Service Cost $ 4.1 $ 3.1 $ 10.3 $ 9.3 Interest Cost 11.8 12.4 30.4 37.1 Expected Return on Plan Assets (16.9) (15.8) (43.2) (47.4) Actuarial Loss 1.7 3.0 4.5 9.1 Prior Service Credit (0.1) (0.7) (0.3) (2.1) Total Net Periodic Benefit Expense $ 0.6 $ 2.0 $ 1.7 $ 6.0 Capitalized PBOP Expense/(Income) $ - $ 1.1 $ 0.1 $ 1.9 Pension and SERP For the Three Months Ended September 30, 2015 For the Three Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 6.2 $ 3.7 $ 3.1 $ 1.0 $ 5.0 $ 3.0 $ 2.3 $ 0.8 Interest Cost 12.9 10.0 6.1 2.6 12.5 10.3 5.7 2.5 Expected Return on Plan Assets (19.8) (17.5) (10.1) (4.7) (18.7) (15.7) (9.3) (4.4) Actuarial Loss 8.0 8.7 2.9 1.6 8.2 5.9 2.8 1.7 Prior Service Cost 0.4 - 0.1 0.1 0.4 - 0.1 0.1 Total Net Periodic Benefit Expense $ 7.7 $ 4.9 $ 2.1 $ 0.6 $ 7.4 $ 3.5 $ 1.6 $ 0.7 Intercompany Allocations $ 5.8 $ 3.4 $ 1.6 $ 1.1 $ 6.5 $ 2.9 $ 1.8 $ 1.2 Capitalized Pension Expense $ 4.7 $ 2.7 $ 0.8 $ 0.5 $ 4.3 $ 2.6 $ 0.7 $ 0.6 Pension and SERP For the Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 18.4 $ 11.2 $ 9.0 $ 3.2 $ 15.2 $ 10.6 $ 7.4 $ 2.7 Interest Cost 38.4 30.2 18.1 7.8 38.1 31.0 18.0 7.8 Expected Return on Plan Assets (59.1) (52.5) (30.3) (14.2) (56.7) (47.3) (28.8) (13.5) Actuarial Loss 24.2 27.0 8.8 4.8 25.5 17.6 8.9 5.2 Prior Service Cost 1.1 0.1 0.4 0.2 1.4 - 0.5 0.3 Total Net Periodic Benefit Expense $ 23.0 $ 16.0 $ 6.0 $ 1.8 $ 23.5 $ 11.9 $ 6.0 $ 2.5 Intercompany Allocations $ 18.0 $ 10.3 $ 5.0 $ 3.3 $ 20.8 $ 6.7 $ 6.0 $ 3.9 Capitalized Pension Expense $ 14.1 $ 8.6 $ 2.6 $ 1.4 $ 13.6 $ 5.5 $ 2.4 $ 2.0 PBOP For the Three Months Ended September 30, 2015 For the Three Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 0.5 $ 1.3 $ 0.3 $ 0.1 $ 0.6 $ 0.8 $ 0.3 $ 0.1 Interest Cost 1.8 4.8 1.0 0.3 2.0 4.9 1.1 0.4 Expected Return on Plan Assets (2.8) (6.8) (1.5) (0.6) (2.6) (6.5) (1.4) (0.6) Actuarial Loss/(Gain) 0.2 0.6 0.1 - 1.0 (0.1) 0.6 0.1 Prior Service Credit - (0.1) - - - (0.5) - - Total Net Periodic Benefit Expense/(Income) $ (0.3) $ (0.2) $ (0.1) $ (0.2) $ 1.0 $ (1.4) $ 0.6 $ 0.0 Intercompany Allocations $ 0.4 $ 0.2 $ 0.1 $ 0.1 $ 0.9 $ 0.3 $ 0.2 $ 0.2 Capitalized PBOP Expense/(Income) $ (0.1) $ - $ 0.1 $ - $ 0.5 $ (0.5) $ 0.2 $ - PBOP For the Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 NSTAR NSTAR (Millions of Dollars) CL&P Electric PSNH (1) WMECO CL&P Electric PSNH WMECO Service Cost $ 1.6 $ 4.0 $ 1.0 $ 0.3 $ 1.7 $ 2.3 $ 1.0 $ 0.3 Interest Cost 5.4 14.2 2.9 1.1 6.0 14.6 3.2 1.3 Expected Return on Plan Assets (8.3) (20.5) (4.4) (1.9) (7.9) (19.5) (4.1) (1.7) Actuarial Loss/(Gain) 0.5 1.8 0.4 - 3.2 (0.4) 1.7 0.3 Prior Service Credit - (0.1) - - - (1.4) - - Total Net Periodic Benefit Expense/(Income) $ (0.8) $ (0.6) $ (0.1) $ (0.5) $ 3.0 $ (4.4) $ 1.8 $ 0.2 Intercompany Allocations $ 1.4 $ 0.7 $ 0.3 $ 0.3 $ 3.1 $ 0.4 $ 0.8 $ 0.6 Capitalized PBOP Expense/(Income) $ (0.2) $ (0.1) $ 0.2 $ (0.1) $ 1.5 $ (1.5) $ 0.6 $ 0.1 (1) Amounts exclude approximately $0.8 million and $2.4 million for the three and nine months ended September 30, 2015, respectively, that represented amounts included in other deferred debits.

Environmental Matters (Tables)

Environmental Matters (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Environmental Loss Contingencies By Site Text Block	As of September 30, 2015 As of December 31, 2014 Reserve Reserve Number of Sites (in millions) Number of Sites (in millions) Eversource 64 $ 46.9 65 $ 43.3 CL&P 14 4.8 16 3.8 NSTAR Electric 14 2.2 13 1.1 PSNH 12 3.4 13 5.2 WMECO 4 0.6 4 0.5

Guarantees and Indemnifications

Guarantees and Indemnifications (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Guarantee Obligations Text Block	Maximum Exposure Company Description (in millions) Expiration Dates On behalf of subsidiaries: Various Surety Bonds (1) $ 33.2 2015 - 2016 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate $ 12.2 2019 and 2024 On behalf of external parties: Purchaser of E.S. Boulos Company and a bonding company E.S. Boulos Company Indemnification $ 38.2 2016 and 2020 Algonquin Gas Transmission, LLC Access Northeast project (owner of Access Northeast assets) capital contributions guarantee $ 206.0 2021

FAIR VALUE OF FINANCIAL INSTR31

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Fair Value By Balance Sheet Grouping Text Block	As of September 30, 2015 As of December 31, 2014 Eversource Carrying Fair Carrying Fair (Millions of Dollars) Amount Value Amount Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 157.3 $ 155.6 $ 153.6 Long-Term Debt 8,986.4 9,419.6 8,851.6 9,451.2 As of September 30, 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 $ 115.4 $ 43.0 $ 41.9 $ - $ - $ - $ - Long-Term Debt 2,975.3 3,285.1 1,792.7 1,931.3 1,076.3 1,135.5 577.8 613.3 As of December 31, 2014 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 $ 112.0 $ 43.0 $ 41.6 $ - $ - $ - $ - Long-Term Debt 2,842.0 3,214.5 1,797.4 1,993.5 1,076.3 1,137.9 628.5 689.4

ACCUMULATED OTHER COMPREHENSI32

ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Accumulated Other Comprehensive Income Loss Table Text Block	For the Nine Months Ended September 30, 2015 For the Nine Months Ended September 30, 2014 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 $ (12.4) $ 0.7 $ (62.3) $ (74.0) $ (14.4) $ 0.4 $ (32.0) $ (46.0) OCI Before Reclassifications - (3.9) (0.4) (4.3) - 0.2 1.2 1.4 Amounts Reclassified from AOCI 1.5 - 3.3 4.8 1.5 - 2.9 4.4 Net OCI 1.5 (3.9) 2.9 0.5 1.5 0.2 4.1 5.8 Balance as of End of Period $ (10.9) $ (3.2) $ (59.4) $ (73.5) $ (12.9) $ 0.6 $ (27.9) $ (40.2)

COMMON SHARES (Tables)

COMMON SHARES (Tables)	3 Months Ended
	Sep. 30, 2015
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 the shares of common stock of CL&P, NSTAR Electric , PSNH and WMECO that were authorized and issued and the respective per share par values : Shares Authorized as of Per Share September 30, 2015 and Issued as of Par Value December 31, 2014 September 30, 2015 December 31, 2014 Eversource $ 5 380,000,000 333,862,615 333,359,172 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 September 30 , 2015 and December 31, 2014 , there were 16,671,366 and 16,375,835 E versource common shares held as treasury shares, respectively. As of September 30 , 2015 and December 31, 2014 , Eversource common sha res outstanding were 317,191,249 and 316 , 983 , 337 , respectively. In May 2015, the Company repurchased 532,521 treasury shares at a share price of $47. 94.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Sep. 30, 2015
Notes To Consolidated Financial Statements [Abstract]
Schedule Of Earnings Per Share Basic And Diluted [Table Text Block]	Eversource For the Three Months Ended For the Nine Months Ended (Millions of Dollars, except share information) September 30, 2015 September 30, 2014 September 30, 2015 September 30, 2014 Net Income Attributable to Common Shareholders $ 235.9 $ 234.6 $ 696.7 $ 597.9 Weighted Average Common Shares Outstanding: Basic 317,452,212 316,340,691 317,296,107 315,941,904 Dilutive Effect 953,057 1,214,234 1,099,935 1,244,586 Diluted 318,405,269 317,554,925 318,396,042 317,186,490 Basic EPS $ 0.74 $ 0.74 $ 2.20 $ 1.89 Diluted EPS $ 0.74 $ 0.74 $ 2.19 $ 1.89

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	3 Months Ended
	Sep. 30, 2015
Segment Reporting Information [Line Items]
Schedule Of Segment Reporting Information By Segment Text Block	For the Three Months Ended September 30, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,543.7 $ 106.2 $ 270.4 $ 211.6 $ (198.8) $ 1,933.1 Depreciation and Amortization (84.5) (17.5) (42.4) (7.1) 0.5 (151.0) Other Operating Expenses (1,140.8) (92.7) (78.3) (199.6) 198.5 (1,312.9) Operating Income 318.4 (4.0) 149.7 4.9 0.2 469.2 Interest Expense (47.4) (9.2) (25.9) (11.2) 1.2 (92.5) Other Income, Net 1.9 (0.2) 3.8 241.9 (242.2) 5.2 Net Income Attributable to Common Shareholders $ 167.5 $ (3.7) $ 78.0 $ 234.9 $ (240.8) $ 235.9 For the Nine Months Ended September 30, 2015 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 4,686.5 $ 799.6 $ 787.2 $ 655.2 $ (664.9) $ 6,263.6 Depreciation and Amortization (342.1) (53.4) (122.6) (21.5) 1.6 (538.0) Other Operating Expenses (3,535.7) (631.5) (225.5) (619.4) 665.2 (4,346.9) Operating Income 808.7 114.7 439.1 14.3 1.9 1,378.7 Interest Expense (140.6) (27.2) (79.8) (35.4) 3.4 (279.6) Other Income, Net 9.6 (0.1) 11.9 777.0 (774.5) 23.9 Net Income Attributable to Common Shareholders $ 418.9 $ 57.3 $ 225.0 $ 764.7 $ (769.2) $ 696.7 Cash Flows Used for Investments in Plant $ 506.5 $ 120.0 $ 493.9 $ 56.9 $ - $ 1,177.3 For the Three Months Ended September 30, 2014 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 1,502.6 $ 109.2 $ 262.5 $ 211.2 $ (193.0) $ 1,892.5 Depreciation and Amortization (71.7) (16.4) (37.4) (13.8) 8.6 (130.7) Other Operating Expenses (1,141.5) (98.4) (74.2) (192.4) 185.6 (1,320.9) Operating Income/(Loss) 289.4 (5.6) 150.9 5.0 1.2 440.9 Interest Expense (49.2) (8.5) (24.5) (8.6) 1.0 (89.8) Other Income, Net 9.3 0.1 2.7 226.4 (226.6) 11.9 Net Income/Loss) Attributable to Common Shareholders $ 153.4 $ (9.9) $ 88.1 $ 228.3 $ (225.3) $ 234.6 For the Nine Months Ended September 30, 2014 Eversource Electric Natural Gas Electric (Millions of Dollars) Distribution Distribution Transmission Other Eliminations Total Operating Revenues $ 4,350.4 $ 737.5 $ 721.4 $ 568.1 $ (516.7) $ 5,860.7 Depreciation and Amortization (309.9) (51.1) (111.4) (28.3) 12.7 (488.0) Other Operating Expenses (3,343.9) (586.2) (211.5) (534.1) 505.6 (4,170.1) Operating Income 696.6 100.2 398.5 5.7 1.6 1,202.6 Interest Expense (143.8) (25.6) (78.8) (27.2) 3.2 (272.2) Other Income, Net 13.6 0.2 6.9 657.9 (659.5) 19.1 Net Income Attributable to Common Shareholders $ 349.1 $ 44.2 $ 206.8 $ 653.4 $ (655.6) $ 597.9 Cash Flows Used for Investments in Plant $ 480.1 $ 120.6 $ 469.9 $ 46.9 $ - $ 1,117.5 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 September 30, 2015 $ 17,836.8 $ 2,986.0 $ 7,773.7 $ 12,750.0 $ (11,300.5) $ 30,046.0 As of December 31, 2014 17,563.4 3,030.9 7,625.6 12,682.5 (11,124.4) 29,778.0

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Sep. 30, 2015
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.

Provision for Uncollectible A37

Provision for Uncollectible Accounts (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	$ 185.8	$ 175.3
Uncollectible Hardship Accounts Receivable Reserve	86.6	91.5
The Connecticut Light And Power Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	79.5	84.3
Uncollectible Hardship Accounts Receivable Reserve	64.9	74
NSTAR Electric Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	46.4	40.7
Public Service Company Of New Hampshire [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	9.4	7.7
Western Massachusetts Electric Company [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Doubtful Accounts Receivable Current	13.2	9.9
Uncollectible Hardship Accounts Receivable Reserve	$ 7.7	$ 6.2

Other Taxes (Details)

Other Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Excise And Sales Taxes	$ 37.8	$ 35	$ 112.9	$ 114.6
The Connecticut Light And Power Company [Member]
Excise And Sales Taxes	$ 35.5	$ 32.5	$ 98	$ 99

Supplemental Cash Flow Inform39

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Capital Expenditures Incurred But Not Yet Paid	$ 160.7	$ 128.9
The Connecticut Light And Power Company [Member]
Capital Expenditures Incurred But Not Yet Paid	46	52.2
NSTAR Electric Company [Member]
Capital Expenditures Incurred But Not Yet Paid	31.2	18.1
Public Service Company Of New Hampshire [Member]
Capital Expenditures Incurred But Not Yet Paid	33.8	21
Western Massachusetts Electric Company [Member]
Capital Expenditures Incurred But Not Yet Paid	$ 15.5	$ 10

Severance Benefits (Details)

Severance Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Notes To Consolidated Financial Statements [Abstract]
Postemployment Benefits Period Expense	$ 1	$ 0.7	$ 2.6	$ 6.5
Postemployment Benefits Liability Current	$ 7.1		$ 7.1		$ 10.4

REGULATORY ACCOUNTING (Details)

REGULATORY ACCOUNTING (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Regulatory Asset [Line Items]
Regulatory Assets, Total	$ 4,605,700	$ 4,726,600
Regulatory Assets Current	653,892	672,493
Regulatory Assets Long Term	3,951,752	4,054,086
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	$ 59,400	60,500
Public Utilities Disclosure Of Regulatory Matters	2015 Regulatory Developments: FERC ROE Complaints: As a result of the March 3, 2015 FERC order in the pending ROE complaint proceedings described in Note 8C, "Commitments and Contingencies – FERC ROE Complaints," in 2015, Eversource 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. NSTAR Electric and NSTAR Gas 2014 Comprehensive Settlement Agreement: On March 2, 2015, the DPU approved the comprehensive settlement agreement between NSTAR Electric, NSTAR Gas and the Massachusetts Attorney General (the "Settlement") as filed with the DPU on December 31, 2014. The Settlement resolved the outstanding NSTAR Electric CPSL program filings for 2006 through 2011, the NSTAR Electric and NSTAR Gas PAM and energy efficiency-related customer billing adjustments reported in 2012, and the recovery of LBR related to NSTAR Electric's energy efficiency programs for 2009 through 2011 (11 dockets in total). In 2015, as a result of the DPU order, NSTAR Electric and NSTAR Gas commenced refunding a combined $44.7 million to customers, which was recorded as a regulatory liability. NSTAR Electric recognized a $21.7 million pre-tax benefit in the first quarter of 2015 as a result of the approval of the Settlement. NSTAR Electric Basic Service Bad Debt Adder: On January 7, 2015, the DPU issued an order concluding that NSTAR Electric had removed energy-related bad debt costs from base distribution rates effective January 1, 2006. As a result of the DPU order, NSTAR Electric increased its regulatory assets and reduced operations and maintenance expense by $24.2 million in the first quarter of 2015, resulting in after-tax earnings of $14.5 million. On May 5, 2015, NSTAR Electric filed for recovery of the energy-related bad debt costs regulatory asset from customers beginning July 1, 2015. On June 24, 2015, the DPU delayed the effective date of NSTAR Electric’s proposed rate increase from July 1, 2015 to November 1, 2015 to allow for the DPU staff to review the reconciliations. NSTAR Electric requested recovery from customers effective January 1, 2016 in briefs filed with the DPU in October 2015. On October 27, 2015, the DPU delayed the effective date of the rate increase from November 1, 2015 to December 1, 2015 to allow the DPU staff additional time to review the reconciliations. NSTAR Electric expects a decision from the DPU in the fourth quarter of 2015. CL&P Distribution Rates: On July 2, 2015, PURA issued a final order that allows for an increase to rate base of approximately $163 million associated with ADIT, including a regulatory asset to recover the incremental revenue requirement for the period December 1, 2014 through November 30, 2015 over a subsequent two-year period. The rate base increase provided an increase to total allowed annual revenue requirements of $18.4 million beginning December 1, 2014. Of that amount, $15.3 million has been recorded as a regulatory asset through September 30, 2015, with a corresponding increase in Operating Revenues.
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	$ 743,700	750,100
Regulatory Liability Current	226,061	235,022
Regulatory Liabilities Long-Term	517,595	515,144
The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,664,300	1,695,800
Regulatory Assets Current	243,293	220,344
Regulatory Assets Long Term	1,420,974	1,475,508
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	2,400	1,300
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	213,300	206,000
Regulatory Liability Current	136,393	124,722
Regulatory Liabilities Long-Term	76,864	81,298
NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,403,500	1,377,800
Regulatory Assets Current	223,520	198,710
Regulatory Assets Long Term	1,179,996	1,179,100
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	21,100	33,200
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	279,600	312,300
Regulatory Liability Current	12,319	49,611
Regulatory Liabilities Long-Term	267,342	262,738
Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	361,900	404,800
Regulatory Assets Current	89,513	111,705
Regulatory Assets Long Term	272,360	293,115
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	3,200	900
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	61,000	67,400
Regulatory Liability Current	11,338	16,044
Regulatory Liabilities Long-Term	49,680	51,372
Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	182,500	198,200
Regulatory Assets Current	48,805	51,923
Regulatory Assets Long Term	133,697	146,307
Regulatory Assets And Liabilities Other Disclosures Abstract
Amount of Regulatory Costs Not yet Approved	16,200	11,000
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	36,200	33,300
Regulatory Liability Current	24,267	22,486
Regulatory Liabilities Long-Term	11,926	10,835
Cost Of Removal [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	433,700	439,900
Cost Of Removal [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	17,200	19,700
Cost Of Removal [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	257,700	258,300
Cost Of Removal [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	49,100	50,300
Cost Of Removal [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	2,000	1,100
Regulatory Tracker Deferrals Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	215,900	192,300
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	131,100	122,600
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	13,000	20,700
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	8,600	14,200
Regulatory Tracker Deferrals Regulatory Liabilities [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	24,200	22,300
AFUDC Transmission Incentive [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	66,200	67,100
AFUDC Transmission Incentive [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	51,800	53,600
AFUDC Transmission Incentive [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	5,400	4,400
AFUDC Transmission Incentive [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	9,000	9,100
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	27,900	50,800
Other Regulatory Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	13,200	10,100
Other Regulatory Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	3,500	28,900
Other Regulatory Liabilities [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	3,300	2,900
Other Regulatory Liabilities [Member] | Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities, Total	1,000	800
Benefit Costs [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,941,800	2,016,000
Benefit Costs [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	434,800	445,400
Benefit Costs [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	486,800	515,900
Benefit Costs [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	171,100	174,300
Benefit Costs [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	84,200	85,000
Regulatory Assets Offsetting Derivative Liabilities [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	412,800	425,500
Regulatory Assets Offsetting Derivative Liabilities [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	406,900	410,900
Regulatory Assets Offsetting Derivative Liabilities [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	1,400	4,500
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	635,800	635,300
Deferred Income Tax Charges Member | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	435,700	437,700
Deferred Income Tax Charges Member | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	83,500	83,700
Deferred Income Tax Charges Member | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	34,200	38,000
Deferred Income Tax Charges Member | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	30,500	35,500
Storm Restoration Costs [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	461,300	502,800
Storm Restoration Costs [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	286,500	319,600
Storm Restoration Costs [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	113,500	103,700
Storm Restoration Costs [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	36,300	47,700
Storm Restoration Costs [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	25,000	31,800
Goodwill Regulatory Asset [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	490,000	505,400
Goodwill Regulatory Asset [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	420,700	433,900
Regulatory Tracker Deferrals Regulatory Assets [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	373,100	350,500
Regulatory Tracker Deferrals Regulatory Assets [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	16,000	16,100
Regulatory Tracker Deferrals Regulatory Assets [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	228,000	141,400
Regulatory Tracker Deferrals Regulatory Assets [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	85,400	103,500
Regulatory Tracker Deferrals Regulatory Assets [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	30,100	33,000
Unrecovered Contractual Obligations [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	142,000	123,800
Other Regulatory Assets [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	148,900	167,300
Other Regulatory Assets [Member] | The Connecticut Light And Power Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	84,400	66,100
Other Regulatory Assets [Member] | NSTAR Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	69,600	94,700
Other Regulatory Assets [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	34,900	41,300
Other Regulatory Assets [Member] | Western Massachusetts Electric Company [Member]
Regulatory Asset [Line Items]
Regulatory Assets, Total	$ 12,700	$ 12,900

PROPERTY, PLANT AND ACCUMULAT42

PROPERTY, PLANT AND ACCUMULATED DEPRECIATION (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	$ 12,821,600	$ 12,495,200
Public Utilities Property Plant And Equipment Distribution Natural Gas	2,657,500	2,595,400
Public Utilities Property Plant And Equipment Transmission	7,260,600	6,930,700
Public Utilities Property Plant And Equipment Generation Or Processing	1,180,000	1,170,900
Public Utilities Property Plant And Equipment Electric And Natural Gas Utility Total	23,919,700	23,192,200
Public Utilities Property Plant And Equipment Other Property Plant And Equipment	555,300	551,300
Public Utilities Property Plant And Equipment Plant In Service	24,475,000	23,743,500
Less Accumulated Depreciation [Abstract]
Electric And Natural Gas Utility Accumulated Depreciation	(6,041,500)	(5,777,800)
Other Accumulated Depreciation	(247,600)	(231,800)
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(6,289,100)	(6,009,600)
Property Plant And Equipment Net Excluding Construction Work In Progress	18,185,900	17,733,900
Public Utilities Property Plant And Equipment Construction Work In Progress	1,220,100	913,100
Property, Plant and Equipment, Net	19,406,025	18,647,041
The Connecticut Light And Power Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	5,289,600	5,158,800
Public Utilities Property Plant And Equipment Transmission	3,480,500	3,274,000
Public Utilities Property Plant And Equipment Generation Or Processing	0	0
Public Utilities Property Plant And Equipment Plant In Service	8,770,100	8,432,800
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(2,007,900)	(1,928,000)
Property Plant And Equipment Net Excluding Construction Work In Progress	6,762,200	6,504,800
Public Utilities Property Plant And Equipment Construction Work In Progress	246,400	304,900
Property, Plant and Equipment, Net	7,008,603	6,809,664
NSTAR Electric Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	5,001,900	4,895,500
Public Utilities Property Plant And Equipment Transmission	1,995,300	1,928,500
Public Utilities Property Plant And Equipment Generation Or Processing	0	0
Public Utilities Property Plant And Equipment Plant In Service	6,997,200	6,824,000
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(1,857,900)	(1,761,400)
Property Plant And Equipment Net Excluding Construction Work In Progress	5,139,300	5,062,600
Public Utilities Property Plant And Equipment Construction Work In Progress	405,800	272,800
Property, Plant and Equipment, Net	5,545,082	5,335,436
Public Service Company Of New Hampshire [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	1,772,000	1,696,700
Public Utilities Property Plant And Equipment Transmission	839,900	789,700
Public Utilities Property Plant And Equipment Generation Or Processing	1,145,500	1,136,500
Public Utilities Property Plant And Equipment Plant In Service	3,757,400	3,622,900
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(1,149,600)	(1,090,000)
Property Plant And Equipment Net Excluding Construction Work In Progress	2,607,800	2,532,900
Public Utilities Property Plant And Equipment Construction Work In Progress	160,400	102,900
Property, Plant and Equipment, Net	2,768,206	2,635,844
Public Service Company Of New Hampshire [Member] | Generation Plant [Member]
Less Accumulated Depreciation [Abstract]
Electric And Natural Gas Utility Accumulated Depreciation	(514,000)
Western Massachusetts Electric Company [Member]
Public Utility Property Plant And Equipment [Line Items]
Public Utilities Property Plant And Equipment Distribution	798,100	784,200
Public Utilities Property Plant And Equipment Transmission	896,700	891,000
Public Utilities Property Plant And Equipment Generation Or Processing	34,500	34,400
Public Utilities Property Plant And Equipment Plant In Service	1,729,300	1,709,600
Less Accumulated Depreciation [Abstract]
Public Utilities, Property, Plant and Equipment, Accumulated Depreciation	(302,600)	(297,400)
Property Plant And Equipment Net Excluding Construction Work In Progress	1,426,700	1,412,200
Public Utilities Property Plant And Equipment Construction Work In Progress	105,000	49,100
Property, Plant and Equipment, Net	$ 1,531,705	$ 1,461,321

DERIVATIVE INSTURMENTS (Details

DERIVATIVE INSTURMENTS (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)$ / KWmo	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)$ / KWmo	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)$ / KWmo$ / REC
Derivative Instrument Detail Abstract
Derivative Liabilities, Noncurrent	$ (365,692)		$ (365,692)		$ (409,632)
Other Derivatives Not Designated As Hedging Instruments At Fair Value Net Total Abstract
Description of Derivative Activity Volume			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 each contract allocated to CL&P and 20 percent 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 September 30, 2015 and December 31, 2014, Eversource had NYMEX financial contracts for natural gas futures in order to reduce variability associated with the purchase price of approximately 9.9 million and 8.8 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	(8,800)	$ (15,700)	$ (58,900)	$ 149,900
Derivative Credit Risk Related Contingent Features Abstract
Derivative Net Liability Position Aggregate Fair Value	(4,600)		(4,600)		(10,000)
Additional Collateral Aggregate Fair Value	4,700		$ 4,700		10,000
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsExitPricePremium			Exit price premiums of 6 percent through 23 percent are also applied on these contracts and reflect the most recent market activity available for similar type contracts
The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	(91,372)		$ (91,372)		(88,459)
Derivative Liabilities, Noncurrent	$ (364,691)		$ (364,691)		(406,199)
Other Derivatives Not Designated As Hedging Instruments At Fair Value Net Total Abstract
Description of Derivative Activity Volume			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 each contract allocated to CL&P and 20 percent 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 Company [Member]
Other Derivatives Not Designated As Hedging Instruments At Fair Value Net Total Abstract
Description of Derivative Activity Volume	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.
Fair Value Inputs Level 2 [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	$ (4,600)		$ (4,600)		(9,800)
Derivative Liabilities, Noncurrent	0		0		(300)
Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	5,800		5,800		9,600
Derivative Liabilities - Current	(92,600)		(92,600)		(90,000)
Derivative Liabilities, Noncurrent	(365,700)		(365,700)		(409,300)
Derivative Assets Noncurrent	$ 45,500		$ 45,500		$ 74,300
Fair Value Inputs Level 3 [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	10.30		10.30		5.30
FairValueInputsRenewableEnergyCreditPrices | $ / KWmo	45		45		38
FairValueInputsForwardReserve | $ / KWmo	2		2		5.80
Fair Value Inputs Level 3 [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	13.13		13.13		12.98
FairValueInputsRenewableEnergyCreditPrices	50		50		56
FairValueInputsForwardReserve | $ / KWmo					9.50
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	$ 5,800		$ 5,800		$ 9,500
Derivative Liabilities - Current	(91,400)		(91,400)		(88,500)
Derivative Liabilities, Noncurrent	(364,700)		(364,700)		(406,200)
Derivative Assets Noncurrent	$ 43,400		$ 43,400		$ 74,300
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	10.81		10.81		11.08
FairValueInputsForwardReserve | $ / KWmo	2		2		5.80
Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	12.60		12.60		12.98
FairValueInputsForwardReserve | $ / KWmo					9.50
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current					$ 100
Derivative Liabilities - Current	$ (1,200)		$ (1,200)		(1,500)
Derivative Liabilities, Noncurrent	(1,000)		(1,000)		$ (3,100)
Derivative Assets Noncurrent	$ 2,100		$ 2,100
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member] | Minimum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	10.30		10.30		5.30
FairValueInputsRenewableEnergyCreditPrices	45		45		38
Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member] | Maximum [Member]
FairValueInputsQuantitativeInformation[Abstract]
FairValueInputsCapacityPrices | $ / KWmo	13.13		13.13		11.10
FairValueInputsRenewableEnergyCreditPrices	50		50		56
Amount Offset Against Derivatives [Member] | Fair Value Inputs Level 2 [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	$ 0		$ 0
Amount Offset Against Derivatives [Member] | Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	(10,800)		(10,800)		$ (6,600)
Derivative Liabilities - Current	0		0
Derivative Assets Noncurrent	(22,200)		(22,200)		(19,200)
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	(10,800)		(10,800)		(6,600)
Derivative Assets Noncurrent	(22,200)		(22,200)		(19,200)
Commodity [Member] | Fair Value Inputs Level 2 [Member]
Derivative Instrument Detail Abstract
Derivative Liabilities - Current	(4,600)		(4,600)		(9,800)
Derivative Liabilities, Noncurrent	0		0		(300)
Commodity [Member] | Fair Value Inputs Level 3 [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	16,600		16,600		16,200
Derivative Liabilities - Current	(92,600)		(92,600)		(90,000)
Derivative Liabilities, Noncurrent	(365,700)		(365,700)		(409,300)
Derivative Assets Noncurrent	67,700		67,700		93,500
Commodity [Member] | Fair Value Inputs Level 3 [Member] | The Connecticut Light And Power Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current	16,600		16,600		16,100
Derivative Liabilities - Current	(91,400)		(91,400)		(88,500)
Derivative Liabilities, Noncurrent	(364,700)		(364,700)		(406,200)
Derivative Assets Noncurrent	65,600		65,600		93,500
Commodity [Member] | Fair Value Inputs Level 3 [Member] | NSTAR Electric Company [Member]
Derivative Instrument Detail Abstract
Derivative Assets - Current					100
Derivative Liabilities - Current	(1,200)		(1,200)		(1,500)
Derivative Liabilities, Noncurrent	(1,000)		(1,000)		$ (3,100)
Derivative Assets Noncurrent	$ 2,100		$ 2,100

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ (422.4)	$ (430.9)	$ (415.4)	$ (635.2)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	(6)	(13.6)	(55.3)	147.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	21.4	21	63.7	64.1
Ending Balance	(407)	(423.5)	(407)	(423.5)
The Connecticut Light And Power Company [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	(420.2)	(424.6)	(410.9)	(630.6)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	(7.6)	(15)	(56.6)	149.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	20.9	18.5	60.6	60.1
Ending Balance	(406.9)	(421.1)	(406.9)	(421.1)
NSTAR Electric Company [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	(2.2)	(6.3)	(4.5)	(7.3)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Gain Loss Included In Reg Asset Liability	1.6	1.4	1.3	0.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	0.5	2.5	3.1	4
Ending Balance	$ (0.1)	$ (2.4)	$ (0.1)	$ (2.4)

MARKETABLE SECURITIES (Details)

MARKETABLE SECURITIES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Marketable Securities, Restricted	$ 430.2		$ 430.2		$ 450.8
Available For Sale Securities Debt Maturities Fair Value Abstract
Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value	56.9		56.9
Available For Sale Securities Debt Maturities After Ten Years Fair Value	121.4		121.4
Available For Sale Securities Debt Maturities After One Year Through Five Years Fair Value	68		68
Available For Sale Securities Debt Maturities Within One Year Fair Value	68.1		68.1
Available For Sale Securities Debt Maturities Fair Value	314.4		314.4
Available For Sale Securities Debt Maturities Amortized Cost Abstract
Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost	67.6		67.6
Available For Sale Securities Debt Maturities Within One Year Amortized Cost	68.1		68.1
Available For Sale Securities Debt Maturities After Ten Years Amortized Cost	119		119
Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost	56.9		56.9
Available For Sale Securities Debt Maturities Amortized Cost	311.6		311.6
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	596.5		596.5		639.2
TradingSecuritiesEquity	14.2		14.2		85.1
IncreaseDecreaseInTradingSecurities	(0.5)	$ (1.9)	1.6	$ 1.9
Western Massachusetts Electric Company [Member]
Available For Sale Securities Debt Maturities Fair Value Abstract
Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value	0.5		0.5
Available For Sale Securities Debt Maturities After Ten Years Fair Value	3.1		3.1
Available For Sale Securities Debt Maturities After One Year Through Five Years Fair Value	14.2		14.2
Available For Sale Securities Debt Maturities Within One Year Fair Value	40.5		40.5
Available For Sale Securities Debt Maturities Fair Value	58.3		58.3
Available For Sale Securities Debt Maturities Amortized Cost Abstract
Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost	14.2		14.2
Available For Sale Securities Debt Maturities Within One Year Amortized Cost	40.5		40.5
Available For Sale Securities Debt Maturities After Ten Years Amortized Cost	3.1		3.1
Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost	0.5		0.5
Available For Sale Securities Debt Maturities Amortized Cost	58.3		58.3
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	58.3		58.3		58.1
Fair Value Inputs Level 1 Member
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	312.8		312.8		343.9
Fair Value Inputs Level 1 Member | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	8		8		4.3
Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	283.7		283.7		295.3
Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	50.3		50.3		53.8
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	41.3		41.3		51.3
US Government Debt Securities Member | Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	0		0		0
Corporate Bond Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	57.5		57.5		49.1
Corporate Bond Securities Member | Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	12.2		12.2		14.7
Asset Backed Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	27.9		27.9		54.1
Asset Backed Securities Member | Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	7.6		7.6		14.5
Municipal Bonds Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	123.9		123.9		116.3
Municipal Bonds Member | Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	10.3		10.3		13
Other Debt Securities Member | Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	33.1		33.1		24.5
Other Debt Securities Member | Fair Value Inputs Level 2 [Member] | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	20.2		20.2		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	30.7		30.7		24.9
Cash And Cash Equivalents Member | Fair Value Inputs Level 1 Member | Western Massachusetts Electric Company [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	8		8		4.3
Mutual Funds [Member] | Fair Value Inputs Level 1 Member
Fair Value Assets And Liabilities Measured On Recurring Basis Abstract
Investments Fair Value Disclosure	282.1		282.1		319
Debt Securities
Investments, Debt and Equity Securities [Abstract]
Available For Sale Securities Fair Value Disclosure	314.4		314.4		320.2
Available-for-sale Securities, Gross Unrealized Gains	3.6				7.5
AvailableForSaleSecuritiesGrossUnrealizedLoss	(0.8)				(0.3)
Available For Sale Securities Amortized Cost	311.6		311.6		313
Debt Securities | Western Massachusetts Electric Company [Member]
Investments, Debt and Equity Securities [Abstract]
Available For Sale Securities Fair Value Disclosure	58.3		58.3		58.1
Available-for-sale Securities, Gross Unrealized Gains	0				0
AvailableForSaleSecuritiesGrossUnrealizedLoss	0				(0.1)
Available For Sale Securities Amortized Cost	58.3		58.3		58.2
Equity Securities
Investments, Debt and Equity Securities [Abstract]
Available For Sale Securities Fair Value Disclosure	267.9		267.9		233.9
Available-for-sale Securities, Gross Unrealized Gains	53.9				73.3
AvailableForSaleSecuritiesGrossUnrealizedLoss	(6)				0
Available For Sale Securities Amortized Cost	$ 220		$ 220		$ 160.6

SHORT AND LONG-TERM TERM DEBT (

SHORT AND LONG-TERM TERM DEBT (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Line of Credit Facility, Description	Credit Agreements and Commercial Paper Programs: On October 26, 2015, Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas amended and restated their joint five-year $1.45 billion revolving credit facility and extended the termination date to September 4, 2020. The facility serves to backstop Eversource parent's $1.45 billion commercial paper program. The commercial paper program allows Eversource parent to issue commercial paper as a form of short-term debt. As of September 30, 2015 and December 31, 2014, Eversource parent had $757 million and approximately $1.1 billion, respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $693 million and $348.9 million of available borrowing capacity as of September 30, 2015 and December 31, 2014, respectively. The weighted-average interest rate on these borrowings as of September 30, 2015 and December 31, 2014 was 0.41 percent and 0.43 percent, respectively. As of September 30, 2015, there were intercompany loans from Eversource parent of $137.3 million to PSNH and $126.2 million to WMECO. As of December 31, 2014, there were intercompany loans from Eversource parent of $133.4 million to CL&P, $90.5 million to PSNH and $21.4 million to WMECO. On October 26, 2015, NSTAR Electric amended and restated its five-year $450 million revolving credit facility and extended the termination date to September 4, 2020. The facility serves to backstop NSTAR Electric's $450 million commercial paper program. As of September 30, 2015 and December 31, 2014, NSTAR Electric had $258.5 million and $302 million, respectively, in short-term borrowings outstanding under its commercial paper program, leaving $191.5 million and $148 million of available borrowing capacity as of September 30, 2015 and December 31, 2014, respectively. The weighted-average interest rate on these borrowings as of September 30, 2015 and December 31, 2014 was 0.18 percent and 0.27 percent, respectively.
Notes Payable	$ 1,015,500	$ 956,825
Long-term Debt, Description	Long-Term Debt: On January 15, 2015, Eversource parent issued $150 million of 1.60 percent Series G Senior Notes, due to mature in 2018 and $300 million of 3.15 percent Series H Senior Notes, due to mature in 2025. The proceeds, net of issuance costs, were used to repay short-term borrowings outstanding under the Eversource parent commercial paper program. As the debt issuances refinanced short-term debt, the short-term debt was classified as Long-Term Debt as of December 31, 2014. On April 1, 2015, CL&P repaid at maturity the $100 million 5.00 percent 2005 Series A First and Refunding Mortgage Bonds using short-term borrowings. On April 1, 2015, CL&P also redeemed the $62 million 1996A Series 1.55 percent PCRBs that were subject to mandatory tender, using short term borrowings. On May 20, 2015, CL&P issued $300 million of 4.15 percent 2015 Series A First and Refunding Mortgage Bonds due to mature in 2045. The proceeds, net of issuance costs, were used to repay short-term borrowings. On August 3, 2015, WMECO repaid at maturity the $50 million 5.24 percent Series C Senior Notes using short-term borrowings. On September 10, 2015, Yankee Gas issued $75 million of 3.35 percent 2015 Series M First Mortgage Bonds due to mature in 2025. The proceeds, net of issuance costs, were used to repay short-term borrowings.
The Connecticut Light And Power Company [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	$ 0	133,400
Long-term Debt, Description	On April 1, 2015, CL&P repaid at maturity the $100 million 5.00 percent 2005 Series A First and Refunding Mortgage Bonds using short-term borrowings. On April 1, 2015, CL&P also redeemed the $62 million 1996A Series 1.55 percent PCRBs that were subject to mandatory tender, using short term borrowings. On May 20, 2015, CL&P issued $300 million of 4.15 percent 2015 Series A First and Refunding Mortgage Bonds due to mature in 2045. The proceeds, net of issuance costs, were used to repay short-term borrowings.
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	$ 191,500	$ 148,000
Short-term Debt, Weighted Average Interest Rate	0.18%	0.27%
CommercialPaper	$ 258,500	$ 302,000
Notes Payable	258,500	302,000
Public Service Company Of New Hampshire [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	137,300	90,500
Western Massachusetts Electric Company [Member]
Line of Credit Facility [Line Items]
Notes Payable To Affiliated Companies	$ 126,200	21,400
Long-term Debt, Description	On August 3, 2015, WMECO repaid at maturity the $50 million 5.24 percent Series C Senior Notes using short-term borrowings.
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	$ 693,000	$ 348,900
Short-term Debt, Weighted Average Interest Rate	0.41%	0.43%
CommercialPaper	$ 757,000	$ 1,100,000

PENSION BENEFITS AND POSTRETI47

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	$ 1,498,346		$ 1,498,346		$ 1,638,558
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Amount That Represents Deferred Regulatory Assets	800		2,400
Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	22,700	$ 19,100	68,700	$ 60,700
Defined Benefit Plan Interest Cost	56,900	56,400	170,300	169,500
Defined Benefit Plan, Expected Return on Plan Assets	(83,900)	(77,700)	(252,100)	(233,100)
Defined Benefit Plan, Amortization of Gains (Losses)	36,500	31,700	111,900	96,500
Defined Benefit Plan Amortization Of Prior Service Cost Credit	900	1,100	2,700	3,300
Defined Benefit Plan Net Periodic Benefit Cost	33,100	30,600	101,500	96,900
Amount Capitalized Defined Benefit Expense	9,800	8,300	31,300	26,700
PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	4,100	3,100	10,300	9,300
Defined Benefit Plan Interest Cost	11,800	12,400	30,400	37,100
Defined Benefit Plan, Expected Return on Plan Assets	(16,900)	(15,800)	(43,200)	(47,400)
Defined Benefit Plan, Amortization of Gains (Losses)	1,700	3,000	4,500	9,100
Defined Benefit Plan Amortization Of Prior Service Cost Credit	(100)	(700)	(300)	(2,100)
Defined Benefit Plan Net Periodic Benefit Cost	600	2,000	1,700	6,000
Amount Capitalized Defined Benefit Expense	0	1,100	100	1,900
The Connecticut Light And Power Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	284,890		284,890		273,854
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	6,200	5,000	18,400	15,200
Defined Benefit Plan Interest Cost	12,900	12,500	38,400	38,100
Defined Benefit Plan, Expected Return on Plan Assets	(19,800)	(18,700)	(59,100)	(56,700)
Defined Benefit Plan, Amortization of Gains (Losses)	8,000	8,200	24,200	25,500
Defined Benefit Plan Amortization Of Prior Service Cost Credit	400	400	1,100	1,400
Defined Benefit Plan Net Periodic Benefit Cost	7,700	7,400	23,000	23,500
Related Intercompany Allocationsof Defined Benefit Expense	5,800	6,500	18,000	20,800
Amount Capitalized Defined Benefit Expense	4,700	4,300	14,100	13,600
The Connecticut Light And Power Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	500	600	1,600	1,700
Defined Benefit Plan Interest Cost	1,800	2,000	5,400	6,000
Defined Benefit Plan, Expected Return on Plan Assets	(2,800)	(2,600)	(8,300)	(7,900)
Defined Benefit Plan, Amortization of Gains (Losses)	200	1,000	500	3,200
Defined Benefit Plan Amortization Of Prior Service Cost Credit			0	0
Defined Benefit Plan Net Periodic Benefit Cost	(300)	1,000	(800)	3,000
Related Intercompany Allocationsof Defined Benefit Expense	400	900	1,400	3,100
Amount Capitalized Defined Benefit Expense	(100)	500	(200)	1,500
NSTAR Electric Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	211,891		211,891		235,529
NSTAR Electric Company [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	3,700	3,000	11,200	10,600
Defined Benefit Plan Interest Cost	10,000	10,300	30,200	31,000
Defined Benefit Plan, Expected Return on Plan Assets	(17,500)	(15,700)	(52,500)	(47,300)
Defined Benefit Plan, Amortization of Gains (Losses)	8,700	5,900	27,000	17,600
Defined Benefit Plan Amortization Of Prior Service Cost Credit	0	0	100	0
Defined Benefit Plan Net Periodic Benefit Cost	4,900	3,500	16,000	11,900
Related Intercompany Allocationsof Defined Benefit Expense	3,400	2,900	10,300	6,700
Amount Capitalized Defined Benefit Expense	2,700	2,600	8,600	5,500
NSTAR Electric Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	1,300	800	4,000	2,300
Defined Benefit Plan Interest Cost	4,800	4,900	14,200	14,600
Defined Benefit Plan, Expected Return on Plan Assets	(6,800)	(6,500)	(20,500)	(19,500)
Defined Benefit Plan, Amortization of Gains (Losses)	600	(100)	1,800	(400)
Defined Benefit Plan Amortization Of Prior Service Cost Credit	(100)	(500)	(100)	(1,400)
Defined Benefit Plan Net Periodic Benefit Cost	(200)	(1,400)	(600)	(4,400)
Related Intercompany Allocationsof Defined Benefit Expense	200	300	700	400
Amount Capitalized Defined Benefit Expense	0	(500)	(100)	(1,500)
Public Service Company Of New Hampshire [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Amortization Of Prior Service Cost Credit		0
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	97,167		97,167		93,243
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	3,100	2,300	9,000	7,400
Defined Benefit Plan Interest Cost	6,100	5,700	18,100	18,000
Defined Benefit Plan, Expected Return on Plan Assets	(10,100)	(9,300)	(30,300)	(28,800)
Defined Benefit Plan, Amortization of Gains (Losses)	2,900	2,800	8,800	8,900
Defined Benefit Plan Amortization Of Prior Service Cost Credit	100	100	400	500
Defined Benefit Plan Net Periodic Benefit Cost	2,100	1,600	6,000	6,000
Related Intercompany Allocationsof Defined Benefit Expense	1,600	1,800	5,000	6,000
Amount Capitalized Defined Benefit Expense	800	700	2,600	2,400
Public Service Company Of New Hampshire [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	300	300	1,000	1,000
Defined Benefit Plan Interest Cost	1,000	1,100	2,900	3,200
Defined Benefit Plan, Expected Return on Plan Assets	(1,500)	(1,400)	(4,400)	(4,100)
Defined Benefit Plan, Amortization of Gains (Losses)	100	600	400	1,700
Defined Benefit Plan Amortization Of Prior Service Cost Credit			0	0
Defined Benefit Plan Net Periodic Benefit Cost	(100)	600	(100)	1,800
Related Intercompany Allocationsof Defined Benefit Expense	100	200	300	800
Amount Capitalized Defined Benefit Expense	100	200	200	600
Western Massachusetts Electric Company [Member]
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued Pension, SERP and PBOP	18,320		18,320		$ 17,705
Western Massachusetts Electric Company [Member] | Pension Plans Defined Benefit Member
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	1,000	800	3,200	2,700
Defined Benefit Plan Interest Cost	2,600	2,500	7,800	7,800
Defined Benefit Plan, Expected Return on Plan Assets	(4,700)	(4,400)	(14,200)	(13,500)
Defined Benefit Plan, Amortization of Gains (Losses)	1,600	1,700	4,800	5,200
Defined Benefit Plan Amortization Of Prior Service Cost Credit	100	100	200	300
Defined Benefit Plan Net Periodic Benefit Cost	600	700	1,800	2,500
Related Intercompany Allocationsof Defined Benefit Expense	1,100	1,200	3,300	3,900
Amount Capitalized Defined Benefit Expense	500	600	1,400	2,000
Western Massachusetts Electric Company [Member] | PBOP Plan
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Defined Benefit Plan Service Cost	100	100	300	300
Defined Benefit Plan Interest Cost	300	400	1,100	1,300
Defined Benefit Plan, Expected Return on Plan Assets	(600)	(600)	(1,900)	(1,700)
Defined Benefit Plan, Amortization of Gains (Losses)	0	100	0	300
Defined Benefit Plan Amortization Of Prior Service Cost Credit			0	0
Defined Benefit Plan Net Periodic Benefit Cost	(200)	0	(500)	200
Related Intercompany Allocationsof Defined Benefit Expense	100	200	300	600
Amount Capitalized Defined Benefit Expense	$ 0	$ 0	$ (100)	$ 100

INCOME TAXES (Details)

INCOME TAXES (Details)	3 Months Ended
	Sep. 30, 2015
Other Tax Disclosures [Abstract]
Other Information Pertaining To Income Taxes	Part of the annual process in making adjustments to these estimates is reconciling the provision for income taxes made during the income tax estimation process to what was filed in the income tax return (return to provision). In the third quarter of 2015, Eversource and CL&P recorded an $8 million and $4.2 million charge, respectively, as a result of reconciling and adjusting its 2014 provision for income taxes to what was filed on its 2014 income tax return. Concurrently, Eversource and CL&P recorded a reversal of state tax reserves in the third quarter of 2015, which resulted in a $5.9 million and $2.2 million benefit, respectively.
The Connecticut Light And Power Company [Member]
Other Tax Disclosures [Abstract]
Other Information Pertaining To Income Taxes	Part of the annual process in making adjustments to these estimates is reconciling the provision for income taxes made during the income tax estimation process to what was filed in the income tax return (return to provision). In the third quarter of 2015, Eversource and CL&P recorded an $8 million and $4.2 million charge, respectively, as a result of reconciling and adjusting its 2014 provision for income taxes to what was filed on its 2014 income tax return. Concurrently, Eversource and CL&P recorded a reversal of state tax reserves in the third quarter of 2015, which resulted in a $5.9 million and $2.2 million benefit, respectively.

Environmental Matters (Details)

Environmental Matters (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Site Contingency [Line Items]
Environmental Site Quantity	64	65
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 43.3
Ending Balance	46.9	$ 43.3
MGP Site accrual [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	38.8
Ending Balance	$ 41	$ 38.8
The Connecticut Light And Power Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	14	16
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 3.8
Ending Balance	$ 4.8	$ 3.8
NSTAR Electric Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	14	13
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 1.1
Ending Balance	$ 2.2	$ 1.1
Public Service Company Of New Hampshire [Member]
Site Contingency [Line Items]
Environmental Site Quantity	12	13
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 5.2
Ending Balance	$ 3.4	$ 5.2
Western Massachusetts Electric Company [Member]
Site Contingency [Line Items]
Environmental Site Quantity	4	4
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning Balance	$ 0.5
Ending Balance	$ 0.6	$ 0.5

Guarantees and Indemnificatio50

Guarantees and Indemnifications (Details)	Sep. 30, 2015USD ($)
Guarantee Of Financial Obligations Of Npt [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 25,000,000
Various Subsidiary Surety Bonds And Performance Guarantees Expiring Between 2015 And 2016 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	33,200,000
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	12,200,000
Guarantee To Purchaser Of Es Boulos Company And A Bonding Company Expiring In 2016 And 2020 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	38,200,000
Access Northeast Project Capital Contributions Guarantee Expiring In 2021 [Member]
Guarantee Obligations [Line Items]
Guarantee Obligations Maximum Exposure	$ 206

Other Contingencies (Details)

Other Contingencies (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Loss Contingencies Line Items
Public Utilities Disclosure Of Regulatory Matters	2015 Regulatory Developments: FERC ROE Complaints: As a result of the March 3, 2015 FERC order in the pending ROE complaint proceedings described in Note 8C, "Commitments and Contingencies – FERC ROE Complaints," in 2015, Eversource 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. NSTAR Electric and NSTAR Gas 2014 Comprehensive Settlement Agreement: On March 2, 2015, the DPU approved the comprehensive settlement agreement between NSTAR Electric, NSTAR Gas and the Massachusetts Attorney General (the "Settlement") as filed with the DPU on December 31, 2014. The Settlement resolved the outstanding NSTAR Electric CPSL program filings for 2006 through 2011, the NSTAR Electric and NSTAR Gas PAM and energy efficiency-related customer billing adjustments reported in 2012, and the recovery of LBR related to NSTAR Electric's energy efficiency programs for 2009 through 2011 (11 dockets in total). In 2015, as a result of the DPU order, NSTAR Electric and NSTAR Gas commenced refunding a combined $44.7 million to customers, which was recorded as a regulatory liability. NSTAR Electric recognized a $21.7 million pre-tax benefit in the first quarter of 2015 as a result of the approval of the Settlement. NSTAR Electric Basic Service Bad Debt Adder: On January 7, 2015, the DPU issued an order concluding that NSTAR Electric had removed energy-related bad debt costs from base distribution rates effective January 1, 2006. As a result of the DPU order, NSTAR Electric increased its regulatory assets and reduced operations and maintenance expense by $24.2 million in the first quarter of 2015, resulting in after-tax earnings of $14.5 million. On May 5, 2015, NSTAR Electric filed for recovery of the energy-related bad debt costs regulatory asset from customers beginning July 1, 2015. On June 24, 2015, the DPU delayed the effective date of NSTAR Electric’s proposed rate increase from July 1, 2015 to November 1, 2015 to allow for the DPU staff to review the reconciliations. NSTAR Electric requested recovery from customers effective January 1, 2016 in briefs filed with the DPU in October 2015. On October 27, 2015, the DPU delayed the effective date of the rate increase from November 1, 2015 to December 1, 2015 to allow the DPU staff additional time to review the reconciliations. NSTAR Electric expects a decision from the DPU in the fourth quarter of 2015. CL&P Distribution Rates: On July 2, 2015, PURA issued a final order that allows for an increase to rate base of approximately $163 million associated with ADIT, including a regulatory asset to recover the incremental revenue requirement for the period December 1, 2014 through November 30, 2015 over a subsequent two-year period. The rate base increase provided an increase to total allowed annual revenue requirements of $18.4 million beginning December 1, 2014. Of that amount, $15.3 million has been recorded as a regulatory asset through September 30, 2015, with a corresponding increase in Operating Revenues.
FERC ROE Reserve - Incentive - First and Second Complaint [Member]
Loss Contingencies Line Items
Loss Contingency Loss in Period		$ 20
FERC ROE Reserve - Incentive - First and Second Complaint [Member] | The Connecticut Light And Power Company [Member]
Loss Contingencies Line Items
Loss Contingency Loss in Period		12.5
FERC ROE Reserve - Incentive - First and Second Complaint [Member] | NSTAR Electric Company [Member]
Loss Contingencies Line Items
Loss Contingency Loss in Period		2.4
FERC ROE Reserve - Incentive - First and Second Complaint [Member] | Public Service Company Of New Hampshire [Member]
Loss Contingencies Line Items
Loss Contingency Loss in Period		1
FERC ROE Reserve - Incentive - First and Second Complaint [Member] | Western Massachusetts Electric Company [Member]
Loss Contingencies Line Items
Loss Contingency Loss in Period		$ 4.1

FAIR VALUE OF FINANCIAL INSTR52

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
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	8,986,400	8,851,600
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	157,300	153,600
Other Long Term Debt	9,419,600	9,451,200
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	2,975,300	2,842,000
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	115,400	112,000
Other Long Term Debt	3,285,100	3,214,500
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	1,792,700	1,797,400
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	41,900	41,600
Other Long Term Debt	1,931,300	1,993,500
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	1,076,300	1,076,300
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	1,135,500	1,137,900
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	577,800	628,500
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	$ 613,300	$ 689,400

ACCUMULATED OTHER COMPREHENSI53

ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			$ (74,009)	$ (46,000)
Other Comprehensive Income Before Reclassifications, Net of Tax			(4,300)	1,400
Reclassification From OCI, Net Of Tax			4,800	4,400
Other Comprehensive Income (Loss), Net of Tax, Total	$ (1,513)	$ 1,335	463	5,859
AOCI Ending Balance	(73,546)	(40,200)	(73,546)	(40,200)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(92,534)	(89,738)	(279,635)	(272,208)
Income Tax Expense	(144,146)	(126,539)	(420,640)	(345,858)
Net Income Attributable to Controlling Interests	235,920	234,614	696,680	597,937
The Connecticut Light And Power Company [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			(931)
Other Comprehensive Income (Loss), Net of Tax, Total	13	104	196	341
AOCI Ending Balance	(735)		(735)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(36,716)	(38,735)	(109,463)	(110,448)
Income Tax Expense	(46,569)	(30,038)	(127,845)	(95,980)
Public Service Company Of New Hampshire [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			(7,369)
Other Comprehensive Income (Loss), Net of Tax, Total	122	277	636	885
AOCI Ending Balance	(6,733)		(6,733)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(11,647)	(11,024)	(34,582)	(33,995)
Income Tax Expense	(20,158)	(17,603)	(56,135)	(52,199)
Western Massachusetts Electric Company [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			(3,176)
Other Comprehensive Income (Loss), Net of Tax, Total	74	83	232	256
AOCI Ending Balance	(2,944)		(2,944)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Abstract]
Total Interest Expense	(5,901)	(6,576)	(19,014)	(18,929)
Income Tax Expense	(9,749)	(10,490)	(28,555)	(26,596)
Qualified Cash Flow Hedging Instruments [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			(12,400)	(14,400)
Reclassification From OCI, Net Of Tax			1,500	1,500
Other Comprehensive Income (Loss), Net of Tax, Total			1,500	1,500
AOCI Ending Balance	(10,900)	(12,900)	(10,900)	(12,900)
Unrealized Gains Losses on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			700	400
Other Comprehensive Income Before Reclassifications, Net of Tax			(3,900)	200
Other Comprehensive Income (Loss), Net of Tax, Total			(3,900)	200
AOCI Ending Balance	(3,200)	600	(3,200)	600
Pension, SERP and PBOP Benefit Plans [Member]
Accumulated Other Comprehensive Income Loss Net Of Tax RollForward [Abstract]
AOCI Beginning Balance			(62,300)	(32,000)
Other Comprehensive Income Before Reclassifications, Net of Tax			(400)	1,200
Reclassification From OCI, Net Of Tax			3,300	2,900
Other Comprehensive Income (Loss), Net of Tax, Total			2,900	4,100
AOCI Ending Balance	$ (59,400)	$ (27,900)	$ (59,400)	$ (27,900)

COMMON SHARES (Details)

COMMON SHARES (Details) - $ / shares	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
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	333,862,615	333,359,172
Treasury Stock Shares	16,671,366	16,375,835
Common Stock, Shares, Outstanding	317,191,249	316,983,337
Treasury Stock Shares Acquired	532,521
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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Notes To Consolidated Financial Statements [Abstract]
Net Income Attributable to Controlling Interests	$ 235,920	$ 234,614	$ 696,680	$ 597,937
Basic	317,452,212	316,340,691	317,296,107	315,941,904
Weighted Average Number Diluted Shares Outstanding Adjustment	953,057	1,214,234	1,099,935	1,244,586
Diluted	318,405,269	317,554,925	318,396,042	317,186,490
Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount	5,894		1,965
Basic Earnings Per Common Share	$ 0.74	$ 0.74	$ 2.20	$ 1.89
Diluted Earnings Per Common Share	$ 0.74	$ 0.74	$ 2.19	$ 1.89

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Operating Revenues	$ 1,933,105	$ 1,892,532	$ 6,263,597	$ 5,860,736
Operating Income	469,238	440,910	1,378,728	1,202,588
Total Interest Expense	(92,534)	(89,738)	(279,635)	(272,208)
Other Income/(Loss), Net	5,241	11,860	23,866	19,054
Income Tax Expense	(144,146)	(126,539)	(420,640)	(345,858)
Net Income	237,799	236,493	702,319	603,576
Net Income Attributable to Noncontrolling Interests	(1,879)	(1,879)	(5,639)	(5,639)
Net Income Attributable to Controlling Interests	235,920	234,614	696,680	597,937
Total Assets	30,046,026		30,046,026		$ 29,777,975
Investments in Property, Plant and Equipment			1,177,285	1,117,493
Electric Distribution Member
Segment Reporting Information [Line Items]
Operating Revenues	1,543,700	1,502,600	4,686,500	4,350,400
Depreciation And Amortization	(84,500)	(71,700)	(342,100)	(309,900)
Operating Expenses, Other	(1,140,800)	(1,141,500)	(3,535,700)	(3,343,900)
Operating Income	318,400	289,400	808,700	696,600
Total Interest Expense	(47,400)	(49,200)	(140,600)	(143,800)
Other Income/(Loss), Net	1,900	9,300	9,600	13,600
Net Income Attributable to Controlling Interests	167,500	153,400	418,900	349,100
Total Assets	17,836,800		17,836,800		17,563,400
Investments in Property, Plant and Equipment			506,500	480,100
Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Operating Revenues	106,200	109,200	799,600	737,500
Depreciation And Amortization	(17,500)	(16,400)	(53,400)	(51,100)
Operating Expenses, Other	(92,700)	(98,400)	(631,500)	(586,200)
Operating Income	(4,000)	(5,600)	114,700	100,200
Total Interest Expense	(9,200)	(8,500)	(27,200)	(25,600)
Other Income/(Loss), Net	(200)	100	(100)	200
Net Income Attributable to Controlling Interests	(3,700)	(9,900)	57,300	44,200
Total Assets	2,986,000		2,986,000		3,030,900
Investments in Property, Plant and Equipment			120,000	120,600
Electric Transmission [Member]
Segment Reporting Information [Line Items]
Operating Revenues	270,400	262,500	787,200	721,400
Depreciation And Amortization	(42,400)	(37,400)	(122,600)	(111,400)
Operating Expenses, Other	(78,300)	(74,200)	(225,500)	(211,500)
Operating Income	149,700	150,900	439,100	398,500
Total Interest Expense	(25,900)	(24,500)	(79,800)	(78,800)
Other Income/(Loss), Net	3,800	2,700	11,900	6,900
Net Income Attributable to Controlling Interests	78,000	88,100	225,000	206,800
Total Assets	7,773,700		7,773,700		7,625,600
Investments in Property, Plant and Equipment			493,900	469,900
Other Segment [Member]
Segment Reporting Information [Line Items]
Operating Revenues	211,600	211,200	655,200	568,100
Depreciation And Amortization	(7,100)	(13,800)	(21,500)	(28,300)
Operating Expenses, Other	(199,600)	(192,400)	(619,400)	(534,100)
Operating Income	4,900	5,000	14,300	5,700
Total Interest Expense	(11,200)	(8,600)	(35,400)	(27,200)
Other Income/(Loss), Net	241,900	226,400	777,000	657,900
Net Income Attributable to Controlling Interests	234,900	228,300	764,700	653,400
Total Assets	12,750,000		12,750,000		12,682,500
Investments in Property, Plant and Equipment			56,900	46,900
Eliminations Segment [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(198,800)	(193,000)	(664,900)	(516,700)
Depreciation And Amortization	500	8,600	1,600	12,700
Operating Expenses, Other	198,500	185,600	665,200	505,600
Operating Income	200	1,200	1,900	1,600
Total Interest Expense	1,200	1,000	3,400	3,200
Other Income/(Loss), Net	(242,200)	(226,600)	(774,500)	(659,500)
Net Income Attributable to Controlling Interests	(240,800)	(225,300)	(769,200)	(655,600)
Total Assets	(11,300,500)		(11,300,500)		(11,124,400)
Investments in Property, Plant and Equipment			0	0
Total [Member]
Segment Reporting Information [Line Items]
Operating Revenues	1,933,100	1,892,500	6,263,600	5,860,700
Depreciation And Amortization	(151,000)	(130,700)	(538,000)	(488,000)
Operating Expenses, Other	(1,312,900)	(1,320,900)	(4,346,900)	(4,170,100)
Operating Income	469,200	440,900	1,378,700	1,202,600
Total Interest Expense	(92,500)	(89,800)	(279,600)	(272,200)
Other Income/(Loss), Net	5,200	11,900	23,900	19,100
Net Income Attributable to Controlling Interests	235,900	$ 234,600	696,700	597,900
Total Assets	$ 30,046,000		30,046,000		$ 29,778,000
Investments in Property, Plant and Equipment			$ 1,177,300	$ 1,117,500