Eversource Energy (ES) 10-Q 4 Aug 17 2017 Q2 Quarterly report Financial data

DOCUMENT AND ENTITY INFORMATION

DOCUMENT AND ENTITY INFORMATION - shares	6 Months Ended
	Jun. 30, 2017	Jul. 31, 2017
Document And Entity [Line Items]
Entity Registrant Name	Eversource Energy
Entity Central Index Key	72,741
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Amendment Flag	false
Trading Symbol	ES
Entity Common Stock, Shares Outstanding (in shares)		316,885,808
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
Entity Common Stock, Shares Outstanding (in shares)		6,035,205
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
Entity Common Stock, Shares Outstanding (in shares)		301
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
Entity Common Stock, Shares Outstanding (in shares)		434,653
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
Entity Common Stock, Shares Outstanding (in shares)		100

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current Assets:
Cash and Cash Equivalents	$ 24,638	$ 30,251
Receivables, Net	833,945	847,301
Unbilled Revenues	158,183	168,490
Fuel, Materials, Supplies and Inventory	286,296	328,721
Regulatory Assets	870,393	887,625
Prepayments and Other Current Assets	157,359	215,284
Total Current Assets	2,330,814	2,477,672
Property, Plant and Equipment, Net	22,071,496	21,350,510
Deferred Debits and Other Assets:
Regulatory Assets	3,580,981	3,638,688
Goodwill	3,519,401	3,519,401
Marketable Securities	565,460	544,642
Other Long-Term Assets	590,688	522,260
Total Deferred Debits and Other Assets	8,256,530	8,224,991
Total Assets	32,658,840	32,053,173
Current Liabilities:
Notes Payable	937,500	1,148,500
Long-Term Debt – Current Portion	1,483,883	773,883
Accounts Payable	587,174	884,521
Regulatory Liabilities	185,930	146,787
Other Current Liabilities	591,222	684,914
Total Current Liabilities	3,785,709	3,638,605
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	5,900,052	5,607,207
Regulatory Liabilities	696,740	702,255
Derivative Liabilities	402,138	413,676
Accrued Pension and SERP	1,073,510	1,141,514
Other Long-Term Liabilities	860,579	853,260
Total Deferred Credits and Other Liabilities	8,933,019	8,717,912
Capitalization:
Long-Term Debt	8,899,021	8,829,354
Noncontrolling Interest - Preferred Stock of Subsidiaries	155,568	155,568
Common Shareholders' Equity:
Common Shares	1,669,392	1,669,392
Capital Surplus, Paid In	6,232,501	6,250,224
Retained Earnings	3,364,336	3,175,171
Accumulated Other Comprehensive Loss	(62,935)	(65,282)
Treasury Stock	(317,771)	(317,771)
Common Stockholder's Equity	10,885,523	10,711,734
Total Capitalization	19,940,112	19,696,656
Total Liabilities and Capitalization	32,658,840	32,053,173
The Connecticut Light And Power Company [Member]
Current Assets:
Cash and Cash Equivalents	5,837	6,579
Receivables, Net	371,504	359,132
Accounts Receivable from Affiliated Companies	22,805	16,851
Unbilled Revenues	50,436	50,373
Materials, Supplies and Inventory	57,324	52,050
Regulatory Assets	346,520	335,526
Prepayments and Other Current Assets	14,608	52,670
Total Current Assets	869,034	873,181
Property, Plant and Equipment, Net	7,940,398	7,632,392
Deferred Debits and Other Assets:
Regulatory Assets	1,343,011	1,391,564
Other Long-Term Assets	138,405	137,907
Total Deferred Debits and Other Assets	1,481,416	1,529,471
Total Assets	10,290,848	10,035,044
Current Liabilities:
Notes Payable to Eversource Parent	101,100	80,100
Long-Term Debt – Current Portion	400,000	250,000
Accounts Payable	229,435	289,532
Accounts Payable to Affiliated Companies	54,046	88,075
Obligations to Third Party Suppliers	52,854	55,520
Regulatory Liabilities	62,195	47,055
Derivative Liabilities	64,301	77,765
Other Current Liabilities	143,998	120,399
Total Current Liabilities	1,107,929	1,008,446
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	2,071,421	1,987,661
Regulatory Liabilities	101,863	100,138
Derivative Liabilities	402,002	412,750
Accrued Pension and SERP	301,691	300,208
Other Long-Term Liabilities	125,996	123,244
Total Deferred Credits and Other Liabilities	3,002,973	2,924,001
Capitalization:
Long-Term Debt	2,513,522	2,516,010
Noncontrolling Interest - Preferred Stock of Subsidiaries	116,200	116,200
Common Shareholders' Equity:
Common Shares	60,352	60,352
Capital Surplus, Paid In	2,110,739	2,110,714
Retained Earnings	1,378,895	1,299,374
Accumulated Other Comprehensive Loss	238	(53)
Common Stockholder's Equity	3,550,224	3,470,387
Total Capitalization	6,179,946	6,102,597
Total Liabilities and Capitalization	10,290,848	10,035,044
NSTAR Electric Company [Member]
Current Assets:
Cash and Cash Equivalents	4,475	3,494
Receivables, Net	261,344	257,557
Accounts Receivable from Affiliated Companies	28,619	8,581
Unbilled Revenues	40,163	31,632
Taxes Receivable	3,532	39,738
Fuel, Materials, Supplies and Inventory	35,067	62,288
Regulatory Assets	270,230	289,400
Prepayments and Other Current Assets	17,730	14,906
Total Current Assets	661,160	707,596
Property, Plant and Equipment, Net	6,188,535	6,051,835
Deferred Debits and Other Assets:
Regulatory Assets	1,064,099	1,057,746
Prepaid PBOP	109,658	95,073
Other Long-Term Assets	71,657	60,572
Total Deferred Debits and Other Assets	1,245,414	1,213,391
Total Assets	8,095,109	7,972,822
Current Liabilities:
Notes Payable	0	126,500
Long-Term Debt – Current Portion	400,000	400,000
Accounts Payable	151,056	232,599
Accounts Payable to Affiliated Companies	8,389	91,532
Obligations to Third Party Suppliers	67,254	55,863
Renewable Portfolio Standards Compliance Obligations	44,258	75,571
Regulatory Liabilities	48,350	63,653
Other Current Liabilities	48,736	71,122
Total Current Liabilities	768,043	1,116,840
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	1,898,526	1,836,292
Regulatory Liabilities	394,527	391,823
Accrued Pension and SERP	111,994	111,827
Other Long-Term Liabilities	130,023	123,194
Total Deferred Credits and Other Liabilities	2,535,070	2,463,136
Capitalization:
Long-Term Debt	2,025,929	1,678,116
Noncontrolling Interest - Preferred Stock of Subsidiaries	43,000	43,000
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	1,047,178	1,045,378
Retained Earnings	1,675,529	1,625,984
Accumulated Other Comprehensive Loss	360	368
Common Stockholder's Equity	2,723,067	2,671,730
Total Capitalization	4,791,996	4,392,846
Total Liabilities and Capitalization	8,095,109	7,972,822
Public Service Company Of New Hampshire [Member]
Current Assets:
Cash and Cash Equivalents	192	4,646
Receivables, Net	81,937	84,450
Accounts Receivable from Affiliated Companies	3,781	4,185
Unbilled Revenues	41,723	41,004
Taxes Receivable	27,122	6,177
Fuel, Materials, Supplies and Inventory	150,066	162,354
Regulatory Assets	132,424	117,240
Prepayments and Other Current Assets	20,514	22,731
Total Current Assets	457,759	442,787
Property, Plant and Equipment, Net	3,118,456	3,039,313
Deferred Debits and Other Assets:
Regulatory Assets	249,612	245,525
Other Long-Term Assets	47,075	37,720
Total Deferred Debits and Other Assets	296,687	283,245
Total Assets	3,872,902	3,765,345
Current Liabilities:
Notes Payable to Eversource Parent	194,100	160,900
Long-Term Debt – Current Portion	180,000	70,000
Accounts Payable	78,218	85,716
Accounts Payable to Affiliated Companies	21,207	29,154
Regulatory Liabilities	13,696	12,659
Other Current Liabilities	46,415	43,253
Total Current Liabilities	533,636	401,682
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	821,799	785,385
Regulatory Liabilities	43,845	44,779
Accrued Pension and SERP	101,143	94,652
Other Long-Term Liabilities	50,051	49,442
Total Deferred Credits and Other Liabilities	1,016,838	974,258
Capitalization:
Long-Term Debt	892,333	1,002,048
Common Shareholders' Equity:
Common Shares	0	0
Capital Surplus, Paid In	843,134	843,134
Retained Earnings	591,288	549,286
Accumulated Other Comprehensive Loss	(4,327)	(5,063)
Common Stockholder's Equity	1,430,095	1,387,357
Total Capitalization	2,322,428	2,389,405
Total Liabilities and Capitalization	3,872,902	3,765,345
Western Massachusetts Electric Company [Member]
Current Assets:
Cash and Cash Equivalents	0	0
Receivables, Net	54,178	54,940
Accounts Receivable from Affiliated Companies	11,393	14,425
Unbilled Revenues	17,335	15,329
Fuel, Materials, Supplies and Inventory	5,784	8,618
Regulatory Assets	67,310	64,123
Prepayments and Other Current Assets	1,821	2,595
Total Current Assets	157,821	160,030
Property, Plant and Equipment, Net	1,719,824	1,678,262
Deferred Debits and Other Assets:
Regulatory Assets	124,899	127,291
Other Long-Term Assets	33,780	29,062
Total Deferred Debits and Other Assets	158,679	156,353
Total Assets	2,036,324	1,994,645
Current Liabilities:
Notes Payable to Eversource Parent	68,700	51,000
Accounts Payable	32,258	56,036
Accounts Payable to Affiliated Companies	28,484	19,478
Obligations to Third Party Suppliers	9,458	10,508
Renewable Portfolio Standards Compliance Obligations	11,114	20,383
Regulatory Liabilities	11,062	14,888
Other Current Liabilities	12,574	14,984
Total Current Liabilities	173,650	187,277
Deferred Credits and Other Liabilities:
Accumulated Deferred Income Taxes	523,028	490,793
Regulatory Liabilities	20,887	17,227
Accrued Pension and SERP	19,798	20,390
Other Long-Term Liabilities	45,471	41,308
Total Deferred Credits and Other Liabilities	609,184	569,718
Capitalization:
Long-Term Debt	566,293	566,536
Common Shareholders' Equity:
Common Shares	10,866	10,866
Capital Surplus, Paid In	444,398	444,398
Retained Earnings	234,051	218,212
Accumulated Other Comprehensive Loss	(2,118)	(2,362)
Common Stockholder's Equity	687,197	671,114
Total Capitalization	1,253,490	1,237,650
Total Liabilities and Capitalization	$ 2,036,324	$ 1,994,645

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues	$ 1,762,811	$ 1,767,184	$ 3,867,946	$ 3,822,819
Operating Expenses:
Purchased Power, Fuel and Transmission	549,704	581,260	1,303,353	1,336,119
Operations and Maintenance	302,714	320,714	632,979	640,850
Depreciation	189,881	176,507	376,686	350,492
Amortization of Regulatory (Liabilities)/Assets, Net	(7,807)	(8,716)	16,210	12,281
Energy Efficiency Programs	116,398	119,667	262,556	256,842
Taxes Other Than Income Taxes	156,234	154,330	311,455	314,277
Total Operating Expenses	1,307,124	1,343,762	2,903,239	2,910,861
Operating Income	455,687	423,422	964,707	911,958
Interest Expense	107,329	100,492	210,758	198,703
Other Income/(Loss), Net	21,543	8,038	35,120	10,049
Income Before Income Tax Expense	369,901	330,968	789,069	723,304
Income Tax Expense	137,272	125,439	295,103	271,742
Net Income	232,629	205,529	493,966	451,562
Net Income Attributable to Noncontrolling Interests	1,880	1,880	3,759	3,759
Net Income Attributable to Common Shareholders	$ 230,749	$ 203,649	$ 490,207	$ 447,803
Basic and Diluted Earnings Per Common Share (in dollars per share)	$ 0.72	$ 0.64	$ 1.54	$ 1.41
Dividends Declared Per Common Share (in dollars per share)	$ 0.48	$ 0.45	$ 0.95	$ 0.89
Weighted Average Common Shares Outstanding:
Basic (in shares)	317,391,365	317,785,495	317,427,258	317,651,319
Diluted (in shares)	317,947,194	318,476,699	318,035,864	318,478,876
The Connecticut Light And Power Company [Member]
Operating Revenues	$ 666,558	$ 679,787	$ 1,398,867	$ 1,415,103
Operating Expenses:
Purchased Power, Fuel and Transmission	207,211	234,504	452,149	507,104
Operations and Maintenance	108,501	122,532	236,727	233,375
Depreciation	60,797	57,532	120,549	114,500
Amortization of Regulatory (Liabilities)/Assets, Net	11,422	(2,988)	24,225	6,891
Energy Efficiency Programs	32,153	35,498	68,744	73,589
Taxes Other Than Income Taxes	70,437	70,568	144,414	146,030
Total Operating Expenses	490,521	517,646	1,046,808	1,081,489
Operating Income	176,037	162,141	352,059	333,614
Interest Expense	35,299	35,978	70,264	72,477
Other Income/(Loss), Net	3,804	6,275	6,561	7,211
Income Before Income Tax Expense	144,542	132,438	288,356	268,348
Income Tax Expense	53,249	49,563	106,855	98,427
Net Income	91,293	82,875	181,501	169,921
NSTAR Electric Company [Member]
Operating Revenues	584,069	591,301	1,187,848	1,205,517
Operating Expenses:
Purchased Power, Fuel and Transmission	197,291	219,189	430,384	473,525
Operations and Maintenance	85,281	88,954	173,632	183,650
Depreciation	56,181	52,571	111,397	104,457
Amortization of Regulatory (Liabilities)/Assets, Net	2,984	3,971	7,961	8,654
Energy Efficiency Programs	59,876	61,922	127,188	128,165
Taxes Other Than Income Taxes	34,648	34,194	62,041	66,750
Total Operating Expenses	436,261	460,801	912,603	965,201
Operating Income	147,808	130,500	275,245	240,316
Interest Expense	23,445	20,216	45,473	41,104
Other Income/(Loss), Net	2,029	2,836	5,277	2,502
Income Before Income Tax Expense	126,392	113,120	235,049	201,714
Income Tax Expense	49,029	44,953	91,524	79,053
Net Income	77,363	68,167	143,525	122,661
Public Service Company Of New Hampshire [Member]
Operating Revenues	230,383	218,517	483,541	460,807
Operating Expenses:
Purchased Power, Fuel and Transmission	60,442	45,653	122,189	95,867
Operations and Maintenance	65,134	63,788	127,484	123,001
Depreciation	32,447	28,644	63,182	56,879
Amortization of Regulatory (Liabilities)/Assets, Net	(18,937)	(8,186)	(13,492)	332
Energy Efficiency Programs	3,287	3,259	7,032	6,879
Taxes Other Than Income Taxes	23,118	22,287	44,001	44,082
Total Operating Expenses	165,491	155,445	350,396	327,040
Operating Income	64,892	63,072	133,145	133,767
Interest Expense	12,970	12,526	25,780	24,987
Other Income/(Loss), Net	456	282	1,654	432
Income Before Income Tax Expense	52,378	50,828	109,019	109,212
Income Tax Expense	20,787	19,573	43,116	41,899
Net Income	31,591	31,255	65,903	67,313
Western Massachusetts Electric Company [Member]
Operating Revenues	120,744	116,396	250,879	244,491
Operating Expenses:
Purchased Power, Fuel and Transmission	33,858	32,665	74,724	72,228
Operations and Maintenance	21,743	22,088	44,242	43,893
Depreciation	12,296	11,476	24,298	22,847
Amortization of Regulatory (Liabilities)/Assets, Net	(361)	992	(849)	2,203
Energy Efficiency Programs	8,079	10,347	18,743	21,203
Taxes Other Than Income Taxes	10,197	9,600	20,624	19,833
Total Operating Expenses	85,812	87,168	181,782	182,207
Operating Income	34,932	29,228	69,097	62,284
Interest Expense	6,182	6,072	12,431	12,075
Other Income/(Loss), Net	272	104	349	(46)
Income Before Income Tax Expense	29,022	23,260	57,015	50,163
Income Tax Expense	11,401	9,995	22,176	20,071
Net Income	$ 17,621	$ 13,265	$ 34,839	$ 30,092

CONDENSED CONSOLIDATED STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net Income	$ 232,629	$ 205,529	$ 493,966	$ 451,562
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	514	534	1,048	1,068
Changes in Unrealized Gains/(Losses) on Marketable Securities	960	1,061	2,605	1,325
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	(2,268)	(1,784)	(1,306)	(913)
Net OCI	(794)	(189)	2,347	1,480
Comprehensive Income Attributable to Noncontrolling Interests	(1,880)	(1,880)	(3,759)	(3,759)
Comprehensive Income Attributable to Common Shareholders	229,955	203,460	492,554	449,283
The Connecticut Light And Power Company [Member]
Net Income	91,293	82,875	181,501	169,921
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	91	111	202	222
Changes in Unrealized Gains/(Losses) on Marketable Securities	33	36	89	45
Net OCI	124	147	291	267
Comprehensive Income Attributable to Common Shareholders	91,417	83,022	181,792	170,188
NSTAR Electric Company [Member]
Net Income	77,363	68,167	143,525	122,661
Other Comprehensive (Loss)/Income, Net of Tax:
Changes in Funded Status of Pension, SERP and PBOP Benefit Plans	(4)	(11)	(8)	(21)
Net OCI	(4)	(11)	(8)	(21)
Comprehensive Income Attributable to Common Shareholders	77,359	68,156	143,517	122,640
Public Service Company Of New Hampshire [Member]
Net Income	31,591	31,255	65,903	67,313
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	290	291	581	581
Changes in Unrealized Gains/(Losses) on Marketable Securities	58	63	155	79
Net OCI	348	354	736	660
Comprehensive Income Attributable to Common Shareholders	31,939	31,609	66,639	67,973
Western Massachusetts Electric Company [Member]
Net Income	17,621	13,265	34,839	30,092
Other Comprehensive (Loss)/Income, Net of Tax:
Qualified Cash Flow Hedging Instruments	110	110	219	219
Changes in Unrealized Gains/(Losses) on Marketable Securities	9	10	25	13
Net OCI	119	120	244	232
Comprehensive Income Attributable to Common Shareholders	$ 17,740	$ 13,385	$ 35,083	$ 30,324

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating Activities:
Net Income	$ 493,966	$ 451,562
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	376,686	350,492
Deferred Income Taxes	269,505	250,851
Pension, SERP and PBOP Expense, Net	11,242	22,659
Pension and PBOP Contributions	(91,400)	(65,929)
Regulatory (Under)/Over Recoveries, Net	85,792	(5,768)
Amortization of Regulatory (Liabilities)/Assets, Net	16,210	12,281
Other	(94,666)	(10,808)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(7,660)	(76,751)
Fuel, Materials, Supplies and Inventory	42,425	43,930
Taxes Receivable/Accrued, Net	23,980	230,075
Accounts Payable	(168,221)	(151,996)
Other Current Assets and Liabilities, Net	(49,889)	(72,160)
Net Cash Flows Provided by Operating Activities	907,970	978,438
Investing Activities:
Investments in Property, Plant and Equipment	(1,146,952)	(869,168)
Proceeds from Sales of Marketable Securities	373,853	327,581
Purchases of Marketable Securities	(394,379)	(322,244)
Other Investing Activities	(11,050)	(2,991)
Net Cash Flows Used in Investing Activities	(1,178,528)	(866,822)
Financing Activities:
Cash Dividends on Common Shares	(301,042)	(282,314)
Cash Dividends on Preferred Stock	(3,759)	(3,759)
Decrease in Notes Payable	(211,000)	(393,953)
Issuance of Long-Term Debt	950,000	800,000
Retirements of Long-Term Debt	(150,000)	(200,000)
Other Financing Activities	(19,254)	(16,811)
Net Cash Flows Provided by/(Used in) Financing Activities	264,945	(96,837)
Net Increase (decrease) in Cash and Cash Equivalents	(5,613)	14,779
Cash and Cash Equivalents - Beginning of Period	30,251	23,947
Cash and Cash Equivalents - End of Period	24,638	38,726
The Connecticut Light And Power Company [Member]
Operating Activities:
Net Income	181,501	169,921
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	120,549	114,500
Deferred Income Taxes	73,277	97,913
Pension, SERP and PBOP (Benefits)/Expense, Net	3,071	3,325
Regulatory (Under)/Over Recoveries, Net	9,762	(40,386)
Amortization of Regulatory (Liabilities)/Assets, Net	24,225	6,891
Other	(27,623)	(4,477)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(22,333)	(26,729)
Taxes Receivable/Accrued, Net	41,733	145,852
Accounts Payable	(63,813)	(38,137)
Other Current Assets and Liabilities, Net	13,541	774
Net Cash Flows Provided by Operating Activities	353,890	429,447
Investing Activities:
Investments in Property, Plant and Equipment	(419,891)	(288,630)
Proceeds from the Sale of Property, Plant and Equipment	0	9,047
Other Investing Activities	132	205
Net Cash Flows Used in Investing Activities	(419,759)	(279,378)
Financing Activities:
Cash Dividends on Common Shares	(99,200)	(99,800)
Capital Contributions from Eversource Parent	0	145,700
Cash Dividends on Preferred Stock	(2,779)	(2,779)
Increase/(Decrease) in Notes Payable to Eversource Parent	21,000	(184,400)
Issuance of Long-Term Debt	300,000	0
Retirements of Long-Term Debt	(150,000)	0
Other Financing Activities	(3,894)	(398)
Net Cash Flows Provided by/(Used in) Financing Activities	65,127	(141,677)
Net Increase (decrease) in Cash and Cash Equivalents	(742)	8,392
Cash and Cash Equivalents - Beginning of Period	6,579	1,057
Cash and Cash Equivalents - End of Period	5,837	9,449
NSTAR Electric Company [Member]
Operating Activities:
Net Income	143,525	122,661
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	111,397	104,457
Deferred Income Taxes	60,673	48,505
Pension and PBOP Contributions	(15,360)	(15,428)
Pension, SERP and PBOP (Benefits)/Expense, Net	(4,944)	2,192
Regulatory (Under)/Over Recoveries, Net	8,257	26,277
Amortization of Regulatory (Liabilities)/Assets, Net	7,961	8,654
Other	(15,309)	(3,978)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(42,050)	(56,140)
Fuel, Materials, Supplies and Inventory	27,221	35,194
Taxes Receivable/Accrued, Net	36,207	45,608
Accounts Payable	(133,614)	(88,774)
Other Current Assets and Liabilities, Net	(45,430)	(64,084)
Net Cash Flows Provided by Operating Activities	138,534	165,144
Investing Activities:
Investments in Property, Plant and Equipment	(262,097)	(199,824)
Other Investing Activities	(3,617)	0
Net Cash Flows Used in Investing Activities	(265,714)	(199,824)
Financing Activities:
Cash Dividends on Common Shares	(93,000)	(278,300)
Capital Contributions from Eversource Parent	1,800	0
Cash Dividends on Preferred Stock	(980)	(980)
Decrease in Notes Payable	(126,500)	266,500
Issuance of Long-Term Debt	350,000	250,000
Retirements of Long-Term Debt	0	(200,000)
Other Financing Activities	(3,159)	(2,495)
Net Cash Flows Provided by/(Used in) Financing Activities	128,161	34,725
Net Increase (decrease) in Cash and Cash Equivalents	981	45
Cash and Cash Equivalents - Beginning of Period	3,494	3,346
Cash and Cash Equivalents - End of Period	4,475	3,391
Public Service Company Of New Hampshire [Member]
Operating Activities:
Net Income	65,903	67,313
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	63,182	56,879
Deferred Income Taxes	37,670	45,976
Regulatory (Under)/Over Recoveries, Net	(1,964)	(10,740)
Amortization of Regulatory (Liabilities)/Assets, Net	(13,492)	332
Other	(6,763)	(8,484)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(1,427)	(5,247)
Fuel, Materials, Supplies and Inventory	12,288	5,394
Taxes Receivable/Accrued, Net	(20,945)	33,840
Accounts Payable	2,236	20,417
Other Current Assets and Liabilities, Net	5,419	(1,422)
Net Cash Flows Provided by Operating Activities	142,107	204,258
Investing Activities:
Investments in Property, Plant and Equipment	(155,737)	(138,713)
Other Investing Activities	26	172
Net Cash Flows Used in Investing Activities	(155,711)	(138,541)
Financing Activities:
Cash Dividends on Common Shares	(23,900)	(38,800)
Capital Contributions from Eversource Parent	0	83,000
Increase/(Decrease) in Notes Payable to Eversource Parent	33,200	(110,400)
Other Financing Activities	(150)	(166)
Net Cash Flows Provided by/(Used in) Financing Activities	9,150	(66,366)
Net Increase (decrease) in Cash and Cash Equivalents	(4,454)	(649)
Cash and Cash Equivalents - Beginning of Period	4,646	1,733
Cash and Cash Equivalents - End of Period	192	1,084
Western Massachusetts Electric Company [Member]
Operating Activities:
Net Income	34,839	30,092
Adjustments to Reconcile Net Income to Net Cash Flows Provided by Operating Activities:
Depreciation	24,298	22,847
Deferred Income Taxes	31,549	17,155
Regulatory (Under)/Over Recoveries, Net	1,170	(2,651)
Amortization of Regulatory (Liabilities)/Assets, Net	(849)	2,203
Other	(3,767)	(2,547)
Changes in Current Assets and Liabilities:
Receivables and Unbilled Revenues, Net	(1,178)	6,500
Taxes Receivable/Accrued, Net	(177)	32,985
Accounts Payable	717	(13,176)
Other Current Assets and Liabilities, Net	(8,942)	2,502
Net Cash Flows Provided by Operating Activities	77,660	95,910
Investing Activities:
Investments in Property, Plant and Equipment	(76,397)	(71,459)
Proceeds from Sales of Marketable Securities	863	1,484
Purchases of Marketable Securities	(826)	(1,457)
Net Cash Flows Used in Investing Activities	(76,360)	(71,432)
Financing Activities:
Cash Dividends on Common Shares	(19,000)	(19,000)
Capital Contributions from Eversource Parent	0	35,000
Increase/(Decrease) in Notes Payable to Eversource Parent	17,700	(89,700)
Issuance of Long-Term Debt	0	50,000
Other Financing Activities	0	(191)
Net Cash Flows Provided by/(Used in) Financing Activities	(1,300)	(23,891)
Net Increase (decrease) in Cash and Cash Equivalents	0	587
Cash and Cash Equivalents - Beginning of Period	0	834
Cash and Cash Equivalents - End of Period	$ 0	$ 1,421

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	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 regulated utility subsidiaries consist of CL&P, NSTAR Electric, PSNH, WMECO, Yankee Gas and NSTAR Gas. Eversource provides energy delivery service to approximately 3.7 million electric and natural gas customers through these six regulated utilities in Connecticut, Massachusetts and New Hampshire. On June 2, 2017, Eversource announced that it had entered into an agreement to acquire Aquarion Water Company ("Aquarion") from Macquarie Infrastructure Partners for $1.675 billion , consisting of approximately $880 million in cash and $795 million of assumed Aquarion debt. The transaction requires approval from PURA, the DPU, the NHPUC, the Maine PUC, and the Federal Communications Commission, and is also subject to a review under the Hart-Scott-Rodino Act. On June 29, 2017, Eversource and Aquarion filed joint applications with regulatory agencies in Connecticut, Massachusetts, New Hampshire and Maine requesting approval of the transaction. The transaction is expected to close by December 31, 2017. The unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH include the accounts of each of 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 Combined Notes to Financial Statements included in Item 8, "Financial Statements and Supplementary Data," of the Eversource 2016 Form 10-K, which was filed with the SEC. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource's, CL&P's, NSTAR Electric's, PSNH's and WMECO's financial position as of June 30, 2017 and December 31, 2016 , the results of operations and comprehensive income for the three and six months ended June 30, 2017 and 2016 , and the cash flows for the six months ended June 30, 2017 and 2016 . The results of operations and comprehensive income for the three and six months ended June 30, 2017 and 2016 and the cash flows for the six months ended June 30, 2017 and 2016 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 assets) 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 differences 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 Accounting Standards Issued but Not Yet Effective: In May 2014, the Financial Accounting Standards Board ("FASB") issued an Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers , which amends existing revenue recognition guidance and is required to be applied retrospectively (either to each reporting period presented or cumulatively at the date of initial application). The Company is evaluating the requirements and potential impacts of ASU 2014-09 and will implement the standard in the first quarter of 2018 cumulatively at the date of initial application. While the guidance continues to be interpreted on an industry specific level, implementation of the ASU is not currently expected to have a material effect on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Liabilities , which is required to be implemented in the first quarter of 2018. The ASU will remove the available-for-sale designation for equity securities, whereby changes in fair value are recorded in accumulated other comprehensive income within shareholders' equity, and will require changes in fair value of all equity securities to be recorded in earnings beginning on January 1, 2018, with the unrealized gain or loss on available-for-sale equity securities as of that date reclassified to retained earnings as a cumulative effect of adoption. The fair value of available-for-sale equity securities subject to this guidance as of June 30, 2017 was approximately $49 million . The remaining available-for-sale equity securities included in marketable securities on the balance sheet are held in nuclear decommissioning trusts and are subject to regulatory accounting treatment and will not be impacted by this guidance. Implementation of the ASU for other financial instruments is not expected to have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO. In February 2016, the FASB issued ASU 2016-02, Leases , which changes existing lease accounting guidance and is required to be applied in the first quarter of 2019, with earlier application permitted. The ASU is required to be implemented for leases beginning on the date of initial application. For prior periods presented, leases are required to be recognized and measured using a modified retrospective approach. The Company is reviewing the requirements of ASU 2016-02, including balance sheet recognition of leases previously deemed operating leases, and expects to implement the ASU in the first quarter of 2019. In March 2017, the FASB issued ASU 2017-07, Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , required to be implemented in the first quarter of 2018. The ASU requires separate presentation of service cost from other components of net pension and PBOP costs, with the other components presented as non-operating income and not subject to capitalization. The Company is assessing the impacts of the ASU on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO; however, implementation of the ASU is not expected to have a material impact on the net income of Eversource, CL&P, NSTAR Electric, PSNH and 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 customer accounts are terminated and these balances are deemed to be uncollectible. The PURA allows CL&P and Yankee Gas to accelerate the recovery of accounts receivable balances attributable to qualified customers under financial or medical duress (uncollectible hardship accounts receivable) outstanding for greater than 180 days and 90 days, respectively. The DPU allows WMECO and NSTAR Gas also to recover in rates, amounts associated with certain uncollectible hardship accounts receivable. Certain of NSTAR Electric's uncollectible hardship accounts receivable are expected to be recovered in future rates, similar to WMECO and NSTAR Gas. These uncollectible customer account balances are included in Regulatory Assets or Other Long-Term Assets on the balance sheets. The total provision for uncollectible accounts and for uncollectible hardship accounts, which is included in the total provision, is included in Receivables, Net on the balance sheets, and was as follows: Total Provision for Uncollectible Accounts Uncollectible Hardship (Millions of Dollars) As of June 30, 2017 As of December 31, 2016 As of June 30, 2017 As of December 31, 2016 Eversource $ 199.0 $ 200.6 $ 124.5 $ 119.9 CL&P 77.5 86.4 64.5 67.7 NSTAR Electric 54.5 54.8 30.7 26.2 PSNH 11.0 9.9 — — WMECO 16.4 15.5 10.6 9.9 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 guidance is also applied to valuations of the investments used to calculate the funded status of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial assets such as goodwill and AROs, and the estimated fair value of preferred stock and long-term debt. Fair Value Hierarchy: In measuring fair value, Eversource uses observable 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 10, "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 income/(loss) related to equity method investments. Investment income/(loss) primarily relates to debt and equity securities held in trust. For further information, see Note 5, "Marketable Securities," to the financial statements. For the three and six months ended June 30, 2017 , Eversource had equity in earnings of $13.3 million and $17.9 million , respectively, related to its equity method investments. F. Other Taxes Gross receipts taxes levied by the state of Connecticut are collected by CL&P and Yankee Gas from their respective customers. These gross receipts taxes are shown separately with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the statements of income as follows: For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Eversource $ 35.7 $ 37.5 $ 77.9 $ 79.8 CL&P 31.8 33.6 65.7 69.6 As agents for state and local governments, Eversource's companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income. G. Supplemental Cash Flow Information Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of June 30, 2017 As of June 30, 2016 Eversource $ 172.0 $ 186.3 CL&P 85.9 59.5 NSTAR Electric 29.5 38.5 PSNH 20.2 31.1 WMECO 10.6 14.6

REGULATORY ACCOUNTING

REGULATORY ACCOUNTING	6 Months Ended
	Jun. 30, 2017
Regulated Operations [Abstract]
REGULATORY ACCOUNTING	REGULATORY ACCOUNTING Eversource's Regulated companies are subject to rate regulation that is based on cost recovery and meets the criteria for application of accounting guidance for rate-regulated operations, which considers the effect of regulation on the timing of the recognition of certain revenues and expenses. The Regulated companies' financial statements reflect the effects of the rate-making process. The rates charged to the customers of Eversource's Regulated companies are designed to collect each company's costs to provide service, including a return on investment. Management believes it is probable that each of the Regulated companies will recover its respective investments in long-lived assets, including regulatory assets. If management were to determine that it could no longer apply the accounting guidance applicable to rate-regulated enterprises to any of the Regulated companies' operations, or if management could not conclude it is probable that costs would be recovered from customers in future rates, the costs would be charged to net income in the period in which the determination is made. Regulatory Assets: The components of regulatory assets were as follows: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Benefit Costs $ 1,833.6 $ 1,817.8 Derivative Liabilities 398.1 423.3 Income Taxes, Net 652.5 644.5 Storm Restoration Costs 352.9 385.3 Goodwill-related 454.2 464.4 Regulatory Tracker Mechanisms 584.3 576.6 Asset Retirement Obligations 103.0 99.3 Other Regulatory Assets 72.8 115.1 Total Regulatory Assets 4,451.4 4,526.3 Less: Current Portion 870.4 887.6 Total Long-Term Regulatory Assets $ 3,581.0 $ 3,638.7 As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Benefit Costs $ 423.5 $ 445.6 $ 189.7 $ 86.4 $ 429.3 $ 438.6 $ 184.2 $ 86.7 Derivative Liabilities 394.8 2.3 — — 420.5 2.8 — — Income Taxes, Net 440.7 91.2 22.4 31.2 437.0 89.7 24.2 30.8 Storm Restoration Costs 210.3 115.3 12.9 14.4 239.8 112.5 17.1 15.9 Goodwill-related — 389.9 — — — 398.7 — — Regulatory Tracker Mechanisms 153.0 240.7 125.7 50.5 123.9 257.3 104.5 46.7 Asset Retirement Obligations 34.5 33.2 16.6 4.4 33.2 31.9 16.2 4.2 Other Regulatory Assets 32.7 16.1 14.7 5.3 43.4 15.6 16.5 7.1 Total Regulatory Assets 1,689.5 1,334.3 382.0 192.2 1,727.1 1,347.1 362.7 191.4 Less: Current Portion 346.5 270.2 132.4 67.3 335.5 289.4 117.2 64.1 Total Long-Term Regulatory Assets $ 1,343.0 $ 1,064.1 $ 249.6 $ 124.9 $ 1,391.6 $ 1,057.7 $ 245.5 $ 127.3 Regulatory Costs in Other Long-Term Assets: Eversource's Regulated companies had $103.0 million (including $3.5 million for CL&P, $40.1 million for NSTAR Electric, $16.4 million for PSNH, and $24.3 million for WMECO) and $86.3 million (including $5.9 million for CL&P, $35.0 million for NSTAR Electric, $8.2 million for PSNH, and $20.1 million for WMECO) of additional regulatory costs as of June 30, 2017 and December 31, 2016 , 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, management believes it is probable that these costs will ultimately be approved and recovered from customers in rates. Regulatory Liabilities: The components of regulatory liabilities were as follows: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Cost of Removal $ 474.4 $ 459.7 Benefit Costs 129.5 136.2 Regulatory Tracker Mechanisms 176.3 145.3 AFUDC - Transmission 65.6 65.8 Other Regulatory Liabilities 36.8 42.1 Total Regulatory Liabilities 882.6 849.1 Less: Current Portion 185.9 146.8 Total Long-Term Regulatory Liabilities $ 696.7 $ 702.3 As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Cost of Removal $ 43.4 $ 277.4 $ 42.8 $ 12.4 $ 38.8 $ 271.6 $ 44.1 $ 8.6 Benefit Costs — 109.4 — — — 113.1 — — Regulatory Tracker Mechanisms 47.5 48.4 11.7 10.9 37.2 63.7 10.7 14.7 AFUDC - Transmission 49.5 7.4 — 8.7 50.2 6.9 — 8.7 Other Regulatory Liabilities 23.7 0.3 3.0 — 21.0 0.2 2.7 0.1 Total Regulatory Liabilities 164.1 442.9 57.5 32.0 147.2 455.5 57.5 32.1 Less: Current Portion 62.2 48.4 13.7 11.1 47.1 63.7 12.7 14.9 Total Long-Term Regulatory Liabilities $ 101.9 $ 394.5 $ 43.8 $ 20.9 $ 100.1 $ 391.8 $ 44.8 $ 17.2

PROPERTY, PLANT AND EQUIPMENT A

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION	PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION The following tables summarize utility property, plant and equipment by asset category: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Distribution - Electric $ 14,012.6 $ 13,716.9 Distribution - Natural Gas 3,094.3 3,010.4 Transmission - Electric 8,817.6 8,517.4 Generation 1,215.4 1,224.2 Electric and Natural Gas Utility 27,139.9 26,468.9 Other (1) 594.0 591.6 Property, Plant and Equipment, Gross 27,733.9 27,060.5 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,706.6 ) (6,480.4 ) Other (262.8 ) (242.0 ) Total Accumulated Depreciation (6,969.4 ) (6,722.4 ) Property, Plant and Equipment, Net 20,764.5 20,338.1 Construction Work in Progress (2) 1,307.0 1,012.4 Total Property, Plant and Equipment, Net $ 22,071.5 $ 21,350.5 (1) These assets are primarily comprised of building improvements, computer software, hardware and equipment at Eversource Service. (2) As of June 30, 2017 , the total CWIP related to NPT was approximately $190 million . As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Distribution $ 5,717.1 $ 5,453.3 $ 2,018.6 $ 863.6 $ 5,562.9 $ 5,402.3 $ 1,949.8 $ 841.9 Transmission 4,016.4 2,530.3 1,103.1 1,119.4 3,912.9 2,435.8 1,059.3 1,061.1 Generation — — 1,179.4 36.0 — — 1,188.2 36.0 Property, Plant and Equipment, Gross 9,733.5 7,983.6 4,301.1 2,019.0 9,475.8 7,838.1 4,197.3 1,939.0 Less: Accumulated Depreciation (2,156.7 ) (2,104.2 ) (1,290.1 ) (352.0 ) (2,082.4 ) (2,025.4 ) (1,254.7 ) (338.8 ) Property, Plant and Equipment, Net 7,576.8 5,879.4 3,011.0 1,667.0 7,393.4 5,812.7 2,942.6 1,600.2 Construction Work in Progress 363.6 309.1 107.5 52.8 239.0 239.1 96.7 78.1 Total Property, Plant and Equipment, Net $ 7,940.4 $ 6,188.5 $ 3,118.5 $ 1,719.8 $ 7,632.4 $ 6,051.8 $ 3,039.3 $ 1,678.3

DERIVATIVE INSTRUMENTS

DERIVATIVE INSTRUMENTS	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS The Regulated companies purchase and procure energy and energy-related products, which are subject to price volatility, for their customers. The costs associated with supplying energy to customers are recoverable from customers in future rates. The Regulated companies manage the risks associated with the price volatility of energy and energy-related products through the use of derivative and non-derivative contracts. Many of the derivative contracts meet the definition of, and are designated as, normal and qualify for accrual accounting under the applicable accounting guidance. The costs and benefits of derivative contracts that meet the definition of normal are recognized in Operating Expenses or Operating Revenues on the statements of income, as applicable, as electricity or natural gas is delivered. Derivative contracts that are not designated as normal are recorded at fair value as current or long-term Derivative Assets or Derivative Liabilities on the balance sheets. For the Regulated companies, regulatory assets or regulatory liabilities are recorded to offset the fair values of derivatives, as contract settlement amounts are recovered from, or refunded to, customers in their respective energy supply rates. The gross fair values of derivative assets and liabilities with the same counterparty are offset and reported as net Derivative Assets or Derivative Liabilities, with current and long-term portions, on the balance sheets. The following table presents the gross fair values of contracts, categorized by risk type, and the net amounts recorded as current or long-term derivative assets or liabilities: As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Commodity Supply and Price Risk Management Netting (1) Net Amount Recorded as a Derivative Commodity Supply and Price Risk Netting (1) Net Amount Recorded as a Derivative Current Derivative Assets: Level 2: Eversource $ — $ — $ — $ 6.0 $ — $ 6.0 Level 3: Eversource, CL&P 11.2 (7.7 ) 3.5 13.9 (9.4 ) 4.5 Long-Term Derivative Assets: Level 2: Eversource $ — $ — $ — $ 0.3 $ (0.1 ) $ 0.2 Level 3: Eversource, CL&P 76.0 (8.0 ) 68.0 77.3 (11.7 ) 65.6 Current Derivative Liabilities: Level 2: Eversource $ (1.1 ) $ 0.1 $ (1.0 ) $ — $ — $ — Level 3: Eversource (66.5 ) — (66.5 ) (79.7 ) — (79.7 ) CL&P (64.3 ) — (64.3 ) (77.8 ) — (77.8 ) NSTAR Electric (2.2 ) — (2.2 ) (1.9 ) — (1.9 ) Long-Term Derivative Liabilities: Level 3: Eversource $ (402.1 ) $ — $ (402.1 ) $ (413.7 ) $ — $ (413.7 ) CL&P (402.0 ) — (402.0 ) (412.8 ) — (412.8 ) NSTAR Electric (0.1 ) — (0.1 ) (0.9 ) — (0.9 ) (1) Amounts represent derivative 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 derivative contracts, see Note 1D, "Summary of Significant Accounting Policies - Fair Value Measurements," to the financial statements. Derivative Contracts at Fair Value with Offsetting Regulatory Amounts Commodity Supply and Price Risk Management : As required by regulation, CL&P, along with UI, has capacity-related contracts with generation facilities. CL&P has a sharing agreement with UI, with 80 percent of the costs or benefits of each contract borne by or allocated to CL&P and 20 percent borne by or allocated to UI. The combined capacity of these contracts is 787 MW. The capacity contracts extend through 2026 and obligate both CL&P and UI to make or receive payments on a monthly basis to or from the generation facilities based on the difference between a set capacity price and the capacity market price received in the ISO-NE capacity markets. In addition, CL&P has a contract to purchase 0.1 million MWh of energy per year through 2020. NSTAR Electric has a renewable energy contract to purchase 0.1 million MWh of energy per year through 2018 and a capacity-related contract to purchase up to 35 MW per year through 2019. As of June 30, 2017 and December 31, 2016 , Eversource had New York Mercantile Exchange ("NYMEX") financial contracts for natural gas futures in order to reduce variability associated with the purchase price of approximately 6.3 million and 9.2 million MMBtu of natural gas, respectively. For the three months ended June 30, 2017 and 2016 , there were losses of $4.4 million and $42.9 million , respectively, deferred as regulatory costs, which reflect the change in fair value associated with Eversource's derivative contracts. For the six months ended June 30, 2017 and 2016, these losses were $30.9 million and $74.4 million , respectively. Fair Value Measurements of Derivative Instruments Derivative contracts classified as Level 2 in the fair value hierarchy relate to the financial contracts for natural gas futures. Prices are obtained from broker quotes and are based on actual market activity. The contracts are valued using NYMEX natural gas prices. Valuations of these contracts also incorporate discount rates using the yield curve approach. The fair value of derivative contracts classified as Level 3 utilizes significant unobservable inputs. The fair value is modeled using income techniques, such as discounted cash flow valuations adjusted for assumptions relating to exit price. Significant observable inputs for valuations of these contracts include energy and energy-related product prices in future years for which quoted prices in an active market exist. Fair value measurements categorized in Level 3 of the fair value hierarchy are prepared by individuals with expertise in valuation techniques, pricing of energy and energy-related products, and accounting requirements. The future power and capacity prices for periods that are not quoted in an active market or established at auction are based on available market data and are escalated based on estimates of inflation in order to address the full term 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 June 30, 2017 As of December 31, 2016 Range Period Covered Range Period Covered Capacity Prices: Eversource, CL&P $ 5.00 — 8.70 per kW-Month 2021 - 2026 $ 5.50 — 8.70 per kW-Month 2020 - 2026 Forward Reserve: Eversource, CL&P $ 1.40 — 2.00 per kW-Month 2017 - 2024 $ 1.40 — 2.00 per kW-Month 2017 - 2024 REC Prices: Eversource, NSTAR Electric $ 26.00 — 27.50 per REC 2017 - 2018 $ 24.00 — 29.00 per REC 2017 - 2018 Exit price premiums of 2 percent through 19 percent are also applied on these contracts and reflect the uncertainty and illiquidity premiums that would be required based on the most recent market activity available for similar type contracts. Significant increases or decreases in future energy or capacity prices in isolation would decrease or increase, respectively, the fair value of the derivative liability. Any increases in risk premiums would increase the fair value of the derivative liability. Changes in these fair values are recorded as a regulatory asset or liability and do not impact net income. Valuations using significant unobservable inputs: The following table presents 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 June 30, 2017 2016 (Millions of Dollars) Eversource CL&P NSTAR Electric Eversource CL&P NSTAR Derivatives, Net: Fair Value as of Beginning of Period $ (416.0 ) $ (413.5 ) $ (2.5 ) $ (387.7 ) $ (385.1 ) $ (2.6 ) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (3.0 ) (0.6 ) (2.4 ) (46.6 ) (46.8 ) 0.2 Settlements 21.9 19.3 2.6 21.7 20.6 1.1 Fair Value as of End of Period $ (397.1 ) $ (394.8 ) $ (2.3 ) $ (412.6 ) $ (411.3 ) $ (1.3 ) For the Six Months Ended June 30, 2017 2016 (Millions of Dollars) Eversource CL&P NSTAR Eversource CL&P NSTAR Derivatives, Net: Fair Value as of Beginning of Period $ (423.3 ) $ (420.5 ) $ (2.8 ) $ (380.9 ) $ (380.8 ) $ (0.1 ) Net Realized/Unrealized Losses Included in Regulatory Assets and Liabilities (18.4 ) (15.2 ) (3.2 ) (76.6 ) (72.2 ) (4.4 ) Settlements 44.6 40.9 3.7 44.9 41.7 3.2 Fair Value as of End of Period $ (397.1 ) $ (394.8 ) $ (2.3 ) $ (412.6 ) $ (411.3 ) $ (1.3 )

MARKETABLE SECURITIES

MARKETABLE SECURITIES	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
MARKETABLE SECURITIES	MARKETABLE SECURITIES Eversource maintains trusts that hold marketable securities to fund certain non-qualified executive benefits. These trusts are not subject to regulatory oversight by state or federal agencies. CYAPC and YAEC maintain legally restricted trusts, each of which holds marketable securities, to fund the spent nuclear fuel removal obligations of their nuclear fuel storage facilities. Trading Securities: Eversource has elected to record certain equity securities as trading securities, with the changes in fair values recorded in Other Income, Net on the statements of income. As of December 31, 2016 , these securities were classified as Level 1 in the fair value hierarchy and totaled $9.6 million . These securities were sold during the first quarter of 2017 and were no longer held as of June 30, 2017 . For the three and six months ended June 30, 2016 , net gains on these securities of $0.2 million and $0.5 million , respectively, were recorded in Other Income, Net on the statements of income. Dividend income is recorded in Other Income, Net when dividends are declared. Available-for-Sale Securities: The following is a summary of available-for-sale securities, which are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of June 30, 2017 As of December 31, 2016 Eversource (Millions of Dollars) Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Debt Securities $ 290.3 $ 4.7 $ (0.5 ) $ 294.5 $ 296.2 $ 1.1 $ (2.1 ) $ 295.2 Equity Securities 202.1 83.2 — 285.3 203.3 62.3 (1.2 ) 264.4 Eversource's debt and equity securities include CYAPC's and YAEC's marketable securities held in nuclear decommissioning trusts in the amounts of $485.9 million and $466.7 million as of June 30, 2017 and December 31, 2016 , respectively. Unrealized gains and losses for these nuclear decommissioning trusts are recorded in Marketable Securities with the corresponding offset to Other Long-Term Liabilities on the balance sheets, with no impact on the statements of income. Unrealized Losses and Other-than-Temporary Impairment: There have been no significant unrealized losses, other-than-temporary impairments or credit losses for the three and six months ended June 30, 2017 and 2016 . 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 recorded in Other Income, Net for Eversource's non-qualified benefit trust and are offset in Other Long-Term Liabilities for CYAPC and YAEC. Eversource utilizes the specific identification basis method for the Eversource non-qualified benefit trust, and the average cost basis method for the CYAPC and YAEC nuclear decommissioning trusts to compute the realized gains and losses on the sale of available-for-sale securities. Contractual Maturities : As of June 30, 2017 , the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Cost Fair Value Less than one year (1) $ 53.0 $ 52.9 One to five years 52.6 53.4 Six to ten years 54.7 56.3 Greater than ten years 130.0 131.9 Total Debt Securities $ 290.3 $ 294.5 (1) Amounts in the Less than one year category include securities in the CYAPC and YAEC nuclear decommissioning trusts, which are restricted and are classified in long-term Marketable Securities on the balance sheets. Fair Value Measurements: The following table presents the marketable securities recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Eversource (Millions of Dollars) As of June 30, 2017 As of December 31, 2016 Level 1: Mutual Funds and Equities $ 285.3 $ 274.0 Money Market Funds 29.7 54.8 Total Level 1 $ 315.0 $ 328.8 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 53.9 $ 63.0 Corporate Debt Securities 67.8 41.1 Asset-Backed Debt Securities 18.6 18.5 Municipal Bonds 113.1 107.5 Other Fixed Income Securities 11.4 10.3 Total Level 2 $ 264.8 $ 240.4 Total Marketable Securities $ 579.8 $ 569.2 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	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
SHORT-TERM AND LONG-TERM DEBT	SHORT-TERM AND LONG-TERM DEBT Commercial Paper Programs and Credit Agreements : Eversource parent has a $1.45 billion commercial paper program allowing Eversource parent to issue commercial paper as a form of short-term debt. As of June 30, 2017 and December 31, 2016 , Eversource parent had $937.5 million and approximately $1.0 billion , respectively, in short-term borrowings outstanding under the Eversource parent commercial paper program, leaving $512.5 million and $428.0 million of available borrowing capacity as of June 30, 2017 and December 31, 2016 , respectively. The weighted-average interest rate on these borrowings as of June 30, 2017 and December 31, 2016 was 1.34 percent and 0.88 percent , respectively. As of June 30, 2017 , there were intercompany loans from Eversource parent of $101.1 million to CL&P, $194.1 million to PSNH, and $68.7 million to WMECO. As of December 31, 2016 , there were intercompany loans from Eversource parent of $80.1 million to CL&P, $160.9 million to PSNH and $51.0 million to WMECO. Eversource parent, CL&P, PSNH, WMECO, NSTAR Gas and Yankee Gas are parties to a five -year $1.45 billion revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop Eversource parent's $1.45 billion commercial paper program. There were no borrowings outstanding on the revolving credit facility as of June 30, 2017 or December 31, 2016 . NSTAR Electric has a $450 million commercial paper program allowing NSTAR Electric to issue commercial paper as a form of short-term debt. As of June 30, 2017 , NSTAR Electric had no short-term borrowings outstanding and as of December 31, 2016 , NSTAR Electric had $126.5 million in short-term borrowings outstanding under its commercial paper program, leaving $450.0 million and $323.5 million of available borrowing capacity as of June 30, 2017 and December 31, 2016 , respectively. The weighted-average interest rate on these borrowings as of December 31, 2016 was 0.71 percent . NSTAR Electric is a party to a five -year $450 million revolving credit facility. The revolving credit facility's termination date is September 4, 2021. The revolving credit facility serves to backstop NSTAR Electric's $450 million commercial paper program. There were no borrowings outstanding on the revolving credit facility as of June 30, 2017 or December 31, 2016 . Amounts outstanding under the commercial paper programs are included in Notes Payable for Eversource and NSTAR Electric and are classified in current liabilities on the balance sheets as all borrowings are outstanding for no more than 364 days at one time. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are included in Notes Payable to Eversource Parent and are classified in current liabilities on their respective balance sheets. Intercompany loans from Eversource parent to CL&P, PSNH and WMECO are eliminated in consolidation on Eversource's balance sheets. Long-Term Debt Issuances: In March 2017, Eversource parent issued $300 million of 2.75 percent Series K Senior Notes due to mature in 2022. The proceeds, net of issuance costs, were used to repay short-term borrowings under the Eversource parent commercial paper program. In March 2017, CL&P issued $300 million of 3.20 percent 2017 Series A First and Refunding Mortgage Bonds due to mature in 2027. The proceeds, net of issuance costs, were used to repay short-term borrowings. In May 2017, NSTAR Electric issued $350 million of 3.20 percent Debentures due to mature in 2027. The proceeds, net of issuance costs, were used to repay short-term borrowings and fund capital expenditures and working capital . Long-Term Debt Repayments: In March 2017, CL&P repaid at maturity the $150 million 5.375 percent 2007 Series A First and Refunding Mortgage Bonds, using short term borrowings. Long-Term Debt Issuance Authorizations: On January 4, 2017, PURA approved CL&P's request for authorization to issue up to $1.325 billion in long-term debt through December 31, 2020. On March 30, 2017, the DPU approved NSTAR Electric's request for authorization to issue up to $700 million in long-term debt through December 31, 2018.

PENSION BENEFITS AND POSTRETIRE

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS	6 Months Ended
	Jun. 30, 2017
Postemployment Benefits [Abstract]
PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS	PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS Eversource Service sponsors a defined benefit retirement plan ("Pension Plan") that covers eligible participants. In addition to the Pension Plan, Eversource maintains non-qualified defined benefit retirement plans sponsored by Eversource Service ("SERP Plans"), which provide benefits in excess of Internal Revenue Code limitations to eligible participants. Eversource Service also sponsors a defined benefit postretirement plan that provides life insurance and a health reimbursement arrangement created for the purpose of reimbursing retirees and dependents for health insurance premiums and certain medical expenses, to eligible participants that meet certain age and service eligibility requirements ("PBOP Plan"). In August 2016, the Company amended its PBOP Plan, which standardized separate benefit structures that existed within the plan and made other benefit changes. The remeasurement resulted in a prior service credit of $5.3 million and $10.7 million for the three and six months ended June 30, 2017 , which was reflected as a reduction to net periodic benefit expense for PBOP benefits. The majority of this amount will be deferred for future refund to customers. 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 portions of pension, SERP and PBOP amounts, are included in Operations and Maintenance expense on the statements of income. Capitalized amounts relate to employees working on capital projects and are included in Property, Plant and Equipment, Net on the balance sheets. Pension, SERP and PBOP expense reflected in the statements of cash flows for CL&P, NSTAR Electric, PSNH and WMECO does not include the intercompany allocations or the corresponding capitalized portion, as these amounts are cash settled on a short-term basis. Pension and SERP Eversource For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Service Cost $ 17.4 $ 18.7 $ 36.4 $ 37.9 Interest Cost 47.2 46.4 93.5 92.8 Expected Return on Pension Plan Assets (83.5 ) (79.5 ) (167.0 ) (159.1 ) Actuarial Loss 33.9 31.3 67.5 63.0 Prior Service Cost 1.1 0.9 2.0 1.8 Total Net Periodic Benefit Expense $ 16.1 $ 17.8 $ 32.4 $ 36.4 Capitalized Pension Expense $ 5.5 $ 5.4 $ 10.9 $ 11.4 PBOP Eversource For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Service Cost $ 2.4 $ 3.1 $ 4.7 $ 6.3 Interest Cost 6.3 9.4 13.5 19.0 Expected Return on Plan Assets (16.0 ) (15.7 ) (31.9 ) (31.5 ) Actuarial Loss 2.5 0.9 4.6 2.1 Prior Service Credit (5.3 ) — (10.7 ) (0.1 ) Total Net Periodic Benefit Income $ (10.1 ) $ (2.3 ) $ (19.8 ) $ (4.2 ) Capitalized PBOP Income $ (4.9 ) $ (1.0 ) $ (9.5 ) $ (1.9 ) Pension and SERP For the Three Months Ended June 30, 2017 For the Three Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 4.6 $ 3.1 $ 2.4 $ 0.7 $ 4.6 $ 3.3 $ 2.5 $ 0.8 Interest Cost 10.5 8.6 5.3 2.1 10.2 8.5 5.1 2.1 Expected Return on Pension Plan Assets (17.8 ) (17.5 ) (10.0 ) (4.4 ) (18.0 ) (16.9 ) (9.6 ) (4.4 ) Actuarial Loss 6.8 8.9 3.0 1.5 6.3 8.7 2.6 1.3 Prior Service Cost 0.4 0.1 0.1 0.1 0.4 — 0.1 0.1 Total Net Periodic Benefit Expense/(Income) $ 4.5 $ 3.2 $ 0.8 $ — $ 3.5 $ 3.6 $ 0.7 $ (0.1 ) Intercompany Allocations $ 2.4 $ 1.8 $ 0.8 $ 0.5 $ 3.5 $ 2.2 $ 1.0 $ 0.6 Capitalized Pension Expense $ 2.4 $ 1.9 $ 0.4 $ 0.1 $ 2.2 $ 2.0 $ 0.4 $ 0.1 Pension and SERP For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 9.3 $ 6.3 $ 4.9 $ 1.5 $ 9.6 $ 6.7 $ 5.0 $ 1.6 Interest Cost 20.9 17.0 10.5 4.2 21.0 16.8 10.3 4.2 Expected Return on Pension Plan Assets (36.0 ) (35.1 ) (19.9 ) (8.9 ) (36.2 ) (33.8 ) (19.3 ) (8.8 ) Actuarial Loss 13.9 17.5 5.8 3.0 13.0 17.0 4.9 2.8 Prior Service Cost 0.7 0.2 0.2 0.2 0.8 — 0.2 0.2 Total Net Periodic Benefit Expense $ 8.8 $ 5.9 $ 1.5 $ — $ 8.2 $ 6.7 $ 1.1 $ — Intercompany Allocations $ 5.0 $ 3.7 $ 1.7 $ 0.9 $ 6.8 $ 4.5 $ 2.0 $ 1.2 Capitalized Pension Expense $ 4.9 $ 3.5 $ 0.7 $ 0.2 $ 4.9 $ 3.7 $ 0.7 $ 0.2 PBOP For the Three Months Ended June 30, 2017 For the Three Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 0.5 $ 0.3 $ 0.3 $ 0.1 $ 0.4 $ 1.0 $ 0.3 $ 0.1 Interest Cost 1.2 1.7 0.7 0.3 1.3 3.8 0.7 0.3 Expected Return on Plan Assets (2.4 ) (6.6 ) (1.3 ) (0.6 ) (2.5 ) (6.4 ) (1.4 ) (0.6 ) Actuarial Loss 0.3 0.8 0.2 — 0.3 0.3 0.1 — Prior Service Cost/(Credit) 0.3 (4.3 ) 0.1 — — — — — Total Net Periodic Benefit Income $ (0.1 ) $ (8.1 ) $ — $ (0.2 ) $ (0.5 ) $ (1.3 ) $ (0.3 ) $ (0.2 ) Intercompany Allocations $ (0.1 ) $ (0.2 ) $ (0.1 ) $ — $ 0.2 $ 0.1 $ — $ — Capitalized PBOP Income $ (0.1 ) $ (4.1 ) $ — $ (0.1 ) $ (0.2 ) $ (0.6 ) $ (0.1 ) $ (0.1 ) PBOP For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 0.9 $ 0.7 $ 0.6 $ 0.2 $ 0.9 $ 1.8 $ 0.6 $ 0.2 Interest Cost 2.7 3.8 1.5 0.5 2.7 7.8 1.5 0.5 Expected Return on Plan Assets (4.8 ) (13.2 ) (2.7 ) (1.1 ) (5.1 ) (12.7 ) (2.8 ) (1.1 ) Actuarial Loss 0.5 1.7 0.3 — 0.5 0.5 0.2 — Prior Service Cost/(Credit) 0.5 (8.6 ) 0.3 0.1 — — — — Total Net Periodic Benefit Income $ (0.2 ) $ (15.6 ) $ — $ (0.3 ) $ (1.0 ) $ (2.6 ) $ (0.5 ) $ (0.4 ) Intercompany Allocations $ (0.4 ) $ (0.5 ) $ (0.2 ) $ (0.1 ) $ 0.3 $ 0.1 $ — $ 0.1 Capitalized PBOP Income $ (0.2 ) $ (7.9 ) $ — $ (0.2 ) $ (0.5 ) $ (1.1 ) $ (0.1 ) $ (0.2 )

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES A. Environmental Matters Eversource, 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. Eversource, CL&P, NSTAR Electric, PSNH and WMECO have an active environmental auditing and training program and each believes it is substantially in compliance with all enacted laws and regulations. The number of environmental sites and related reserves for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: As of June 30, 2017 As of December 31, 2016 Number of Sites Reserve (in millions) Number of Sites Reserve (in millions) Eversource 58 $ 57.7 61 $ 65.8 CL&P 14 5.1 14 4.9 NSTAR Electric 11 2.2 13 3.2 PSNH 11 5.7 11 5.3 WMECO 4 0.7 4 0.6 Included in the Eversource number of sites and reserve amounts above are former MGP sites that were operated several decades ago and manufactured gas from coal and other processes, which resulted in certain by-products remaining in the environment that may pose a potential risk to human health and the environment, for which Eversource may have potential liability. The reserve balances related to these former MGP sites were $51.7 million and $59.0 million as of June 30, 2017 and December 31, 2016 , respectively, and related primarily to the natural gas business segment. The reduction in the reserve balance at the MGP sites was primarily due to a change in cost estimates at one site where actual contamination was less than originally estimated. These reserve estimates are subjective in nature as they take into consideration several different remediation options at each specific site. The reliability and precision of these estimates can be affected by several factors, including new information concerning either the level of contamination at the site, the extent of Eversource's, CL&P's, NSTAR Electric's, PSNH's, and WMECO's responsibility for remediation or the extent of remediation required, recently enacted laws and regulations, or changes in cost estimates due to certain economic factors. It is possible that new information or future developments could require a reassessment of the potential exposure to related environmental matters. As this information becomes available, management will continue to assess the potential exposure and adjust the reserves accordingly. B. Guarantees and Indemnifications In the normal course of business, Eversource parent provides credit assurances on behalf of its subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, in the form of guarantees. Eversource parent issued a guaranty on behalf of its subsidiary, NPT, under which, beginning at the time the Northern Pass Transmission line goes into commercial operation, Eversource parent will guarantee the financial obligations of NPT under the TSA with HQ in an amount not to exceed $25 million . Eversource parent's obligations under the guaranty expire upon the full, final and indefeasible payment of the guaranteed obligations. Eversource parent has also entered into a guaranty on behalf of NPT under which Eversource parent will guarantee NPT's obligations under a facility with a financial institution pursuant to which NPT may request letters of credit in an aggregate amount of up to approximately $14 million . Eversource parent has also guaranteed certain indemnification and other obligations as a result of the sales of former unregulated subsidiaries and the termination of an unregulated business, with maximum exposures either not specified or not material. Management does not anticipate a material impact to net income or cash flows as a result of these various guarantees and indemnifications. The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries to external parties, as of June 30, 2017 : Company Description Maximum Exposure (in millions) Expiration Dates On behalf of subsidiaries: Eversource Gas Transmission LLC Access Northeast Project Capital Contributions Guaranty (1) $ 185.1 2021 Various Surety Bonds (2) 40.1 2017 - 2018 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate 8.5 2019 - 2024 (1) Eversource parent issued a declining balance guaranty on behalf of its subsidiary, Eversource Gas Transmission LLC, to guarantee the payment of the subsidiary's capital contributions for its investment in the Access Northeast project. The guaranty decreases as capital contributions are made. The guaranty will expire upon the earlier of the full performance of the guaranteed obligations or December 31, 2021. (2) Surety bond expiration dates reflect termination dates, the majority of which will be renewed or extended. Certain surety bonds contain credit ratings triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource parent are downgraded. C. FERC ROE Complaints Four separate complaints have been filed at the FERC by combinations of New England state attorneys general, state regulatory commissions, consumer advocates, consumer groups, municipal parties and other parties (collectively the "Complainants"). In each of the first three complaints, the Complainants challenged the NETOs' base ROE of 11.14 percent that had been utilized since 2005 and sought an order to reduce it prospectively from the date of the final FERC order and for the separate 15 -month complaint periods. In the fourth complaint, filed April 29, 2016, the Complainants challenged the NETOs' base ROE of 10.57 percent and the maximum ROE for transmission incentive ("incentive cap") of 11.74 percent , asserting that these ROEs were unjust and unreasonable. In response to appeals of the FERC decision in the first complaint filed by the NETOs and the Complainants, the U.S. Court of Appeals for the D.C. Circuit (the "Court") issued a decision on April 14, 2017 vacating and remanding the FERC's decision. The Court found that the FERC failed to make an explicit finding that the 11.14 percent base ROE was unjust and unreasonable, as required under Section 206 of the Federal Power Act, before it set a new base ROE. The Court also found that the FERC did not provide a rational connection between the record evidence and its decision to select the midpoint of the upper half of the zone of reasonableness for the new base ROE. On May 26, 2017, the Chief Administrative Law Judge ("ALJ") issued an order that the fourth complaint will continue to trial in December 2017 with an ALJ initial decision expected in March of 2018. A summary of the four separate complaints and the base ROEs pertinent to those complaints are as follows: Complaint 15-Month Time Period of Complaint (Beginning as of Complaint Filing Date) Original Base ROE Authorized by FERC at Time of Complaint Filing Date (1) Base ROE Subsequently Authorized by FERC for First Complaint Period and also Effective from October 16, 2014 through April 14, 2017 (1) Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions) FERC ALJ Recommendation of Base ROE on Second and Third Complaints (Issued March 22, 2016) First 10/1/2011 - 12/31/2012 11.14% 10.57% $— (2) N/A Second 12/27/2012 - 3/26/2014 11.14% N/A 39.1 (3) 9.59% Third 7/31/2014 - 10/30/2015 11.14% 10.57% — 10.90% Fourth 4/29/2016 - 7/28/2017 10.57% 10.57% — N/A (1) The billed ROE (base plus incentives) between October 1, 2011 and October 15, 2014 was within a range of 11.14 percent to 13.1 percent . On October 16, 2014, the FERC set the incentive cap at 11.74 percent for the first complaint period and also effective from October 16, 2014 through April 14, 2017, at which time the Court vacated this FERC order. (2) CL&P, NSTAR Electric, PSNH and WMECO have refunded all amounts associated with the first complaint period, totaling $38.9 million (pre-tax and excluding interest) at Eversource (including $22.4 million at CL&P, $8.4 million at NSTAR Electric, $2.8 million at PSNH, and $5.3 million at WMECO), reflecting both the base ROE and incentive cap prescribed by the FERC order. (3) The reserve represents the difference between the ROEs billed during the second complaint period and a 10.57 percent base ROE and 11.74 percent incentive cap. The reserve was $21.4 million for CL&P, $8.5 million for NSTAR Electric, $3.1 million for PSNH, and $6.1 million for WMECO as of June 30, 2017 . On June 5, 2017, the NETOs, including Eversource, submitted a filing at the FERC to reinstate the base ROE of 11.14 percent with an associated ROE incentive cap of 13.5 percent effective June 8, 2017, as these were the last ROEs lawfully in effect for transmission billing purposes prior to the FERC order vacated by the Court on April 14, 2017. The NETOs have voluntarily delayed the date on which they will begin billing the reinstated ROEs until 60 days after the FERC has a quorum again. If the FERC takes no action within that 60 -day period, the NETOs will begin billing the reinstated ROEs, subject to refund. The Company will continue to recognize transmission revenues as billed utilizing a base ROE of 10.57 percent with an incentive cap of 11.74 percent , until further FERC action or upon expiration of the 60-day period with no FERC action. The Company will change the amounts it is using to recognize transmission revenues only upon a change in the rates billed to its customers. At this time, the Company cannot reasonably estimate a range of gain or loss for the complaint proceedings. The April 14, 2017 Court decision did not provide a reasonable basis for a change to the reserve balance of $39.1 million (pre-tax and excluding interest) for the second complaint period, and the Company has not changed its reserves or recognized ROEs for any of the complaint periods. Management cannot at this time predict the ultimate effect of the Court decision on any of the complaint periods or the estimated impacts on the financial position, results of operations or cash flows of Eversource, CL&P, NSTAR Electric, PSNH and WMECO. The average impact of a 10 basis point change to the base ROE for each of the 15 -month complaint periods would affect Eversource's after-tax earnings by approximately $3 million . D. Eversource and NSTAR Electric Boston Harbor Civil Action On July 15, 2016, the United States Attorney on behalf of the United States Army Corps of Engineers filed a civil action in the United States District Court for the District of Massachusetts under provisions of the Rivers and Harbors Act of 1899 and the Clean Water Act against NSTAR Electric, Harbor Electric Energy Company, a wholly-owned subsidiary of NSTAR Electric ("HEEC"), and the Massachusetts Water Resources Authority (together with NSTAR Electric and HEEC, the "Defendants"). The action alleged that the Defendants failed to comply with certain permitting requirements related to the placement of the HEEC-owned electric distribution cable beneath Boston Harbor. The action sought an order to force HEEC to comply with cable depth requirements in the United States Army Corps of Engineers' permit or alternatively to remove the electric distribution cable and cease unauthorized work in U.S. waterways. The action also sought civil penalties and other costs. After substantial negotiations, the parties reached a settlement whereby HEEC will install a new 115 kV distribution cable across Boston Harbor to Deer Island, utilizing a different route, and will remove portions of the existing cable. Upon the installation and completion of the new cable and the removal of the portions of the existing cable, all issues surrounding the current permit from the United States Army Corps of Engineers are expected to be resolved, and such litigation is expected to be dismissed with prejudice. In the second quarter of 2017, as a result of the settlement, NSTAR Electric expensed $4.9 million (pre-tax) of previously incurred capitalized costs associated with engineering work performed on the existing cable that will no longer be used. In addition, NSTAR Electric agreed to provide a rate base credit of $17.5 million that will be credited to the rates charged to the Massachusetts Water Resources Authority for the new cable. This negotiated credit will result in the initial $17.5 million of construction costs on the new cable to be expensed as incurred. Construction of the new cable will be completed in 2019.

PSNH GENERATION ASSET SALE

PSNH GENERATION ASSET SALE	6 Months Ended
	Jun. 30, 2017
Regulated Operations [Abstract]
PSNH GENERATION ASSET SALE	PSNH GENERATION ASSET SALE On June 10, 2015, Eversource and PSNH entered into the 2015 Public Service Company of New Hampshire Restructuring and Rate Stabilization Agreement (the "Agreement") with the New Hampshire Office of Energy and Planning, certain members of the NHPUC staff, the Office of Consumer Advocate, two State Senators, and several other parties. Under the terms of the Agreement, PSNH agreed to divest its generation assets, subject to NHPUC approval. The Agreement provided for a resolution of issues pertaining to PSNH's generation assets in pending regulatory proceedings before the NHPUC. The Agreement provided for the Clean Air Project prudence proceeding to be resolved and all remaining Clean Air Project costs to be included in rates effective January 1, 2016. As part of the Agreement, PSNH agreed to forego recovery of $25 million of the equity return related to the Clean Air Project. On July 1, 2016, the NHPUC approved the Agreement in an order that, among other things, instructed PSNH to begin the process of divesting its generation assets. The NHPUC selected an auction adviser to assist with the divestiture, and the final plan and auction process were approved by the NHPUC in November 2016. An intervening appeal alleging that the auction process and schedule were unreasonable was rejected by the New Hampshire Supreme Court in February 2017. In late March 2017, the formal divestiture process began. The Company expects the transaction to be approved by the end of 2017. The sales price of the generation assets could be less than the carrying value, but the Company believes that full recovery of PSNH's generation assets is probable through a combination of cash flows during the remaining operating period, sales proceeds upon divestiture, and recovery of stranded costs via bonds that will be secured by a non-bypassable charge or through recoveries in future rates billed to PSNH's customers. As of June 30, 2017 , PSNH's generation assets were as follows: (Millions of Dollars) Gross Plant $ 1,183.3 Accumulated Depreciation (564.1 ) Net Plant 619.2 Fuel 94.6 Materials and Supplies 36.3 Emission Allowances 19.5 Total Generation Assets $ 769.6 As of June 30, 2017 , current and long-term liabilities associated with PSNH's generation assets included Accounts Payable of $30.2 million , Other Current Liabilities of $17.6 million , AROs of $20.6 million , and Accrued Pension, SERP and PBOP of $23.9 million .

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	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 projections. 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 June 30, 2017 As of December 31, 2016 Eversource (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 158.4 $ 155.6 $ 158.3 Long-Term Debt 10,382.9 10,935.8 9,603.2 9,980.5 CL&P NSTAR Electric PSNH WMECO (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value As of June 30, 2017: Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 115.0 $ 43.0 $ 43.4 $ — $ — $ — $ — Long-Term Debt 2,913.5 3,247.3 2,425.9 2,605.9 1,072.3 1,122.3 566.3 602.8 As of December 31, 2016: Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 114.7 $ 43.0 $ 43.6 $ — $ — $ — $ — Long-Term Debt 2,766.0 3,049.6 2,078.1 2,201.6 1,072.0 1,109.7 566.5 589.0 Derivative Instruments and Marketable Securities: Derivative instruments and investments in marketable securities are carried at fair value. For further information, see Note 4, "Derivative Instruments," and Note 5, "Marketable Securities," to the financial statements. See Note 1D, "Summary of Significant Accounting Policies - Fair Value Measurements," for the fair value measurement policy and the fair value hierarchy.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS)	ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) The changes in accumulated other comprehensive income/(loss) by component, net of tax, is as follows: For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 Qualified Unrealized Qualified Unrealized Cash Flow Gains Cash Flow Gains/(Losses) Eversource (Millions of Dollars) Hedging on Marketable Defined Hedging on Marketable Defined Instruments Securities Benefit Plans Total Instruments Securities Benefit Plans Total Balance as of Beginning of Period $ (8.2 ) $ 0.4 $ (57.5 ) $ (65.3 ) $ (10.3 ) $ (1.9 ) $ (54.6 ) $ (66.8 ) OCI Before Reclassifications — 2.6 (3.5 ) (0.9 ) — 1.3 (2.6 ) (1.3 ) Amounts Reclassified from AOCL 1.1 — 2.2 3.3 1.1 — 1.6 2.7 Net OCI 1.1 2.6 (1.3 ) 2.4 1.1 1.3 (1.0 ) 1.4 Balance as of End of Period $ (7.1 ) $ 3.0 $ (58.8 ) $ (62.9 ) $ (9.2 ) $ (0.6 ) $ (55.6 ) $ (65.4 ) Eversource'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 AOCL 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 AOCL into Interest Expense over the remaining life of the associated long-term debt. Such interest rate swaps are not material to their respective financial statements. Defined benefit plan OCI amounts before reclassifications relate to actuarial gains and losses and prior service costs that arose during the year and were recognized in AOCL. The unamortized actuarial gains and losses and prior service costs on the defined benefit plans are amortized from AOCL into Operations and Maintenance expense over the average future employee service period, and are reflected in amounts reclassified from AOCL. For further information, see Note 7, "Pension Benefits and Postretirement Benefits Other Than Pensions."

COMMON SHARES

COMMON SHARES	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
COMMON SHARES	COMMON SHARES The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric, PSNH and WMECO that were authorized and issued, as well as the respective per share par values: Shares Authorized as of June 30, 2017 and Issued as of Par Value December 31, 2016 June 30, 2017 December 31, 2016 Eversource $ 5 380,000,000 333,878,402 333,878,402 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 100 100 PSNH $ 1 100,000,000 301 301 WMECO $ 25 1,072,471 434,653 434,653 As of both June 30, 2017 and December 31, 2016 , there were 16,992,594 Eversource common shares held as treasury shares. As of both June 30, 2017 and December 31, 2016 , Eversource common shares outstanding were 316,885,808 . COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS Dividends on the preferred stock of CL&P and NSTAR Electric totaled $1.9 million for both of the three months ended June 30, 2017 and 2016 , and $3.8 million for both of the six months ended June 30, 2017 and 2016 . These dividends were presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. Noncontrolling Interest – Preferred Stock of Subsidiaries on the Eversource balance sheets totaled $155.6 million as of June 30, 2017 and December 31, 2016 . On the Eversource balance sheets, Common Shareholders' Equity was fully attributable to the parent and Noncontrolling Interest – Preferred Stock of Subsidiaries was fully attributable to the noncontrolling interest.

COMMON SHAREHOLDERS' EQUITY AND

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	COMMON SHARES The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric, PSNH and WMECO that were authorized and issued, as well as the respective per share par values: Shares Authorized as of June 30, 2017 and Issued as of Par Value December 31, 2016 June 30, 2017 December 31, 2016 Eversource $ 5 380,000,000 333,878,402 333,878,402 CL&P $ 10 24,500,000 6,035,205 6,035,205 NSTAR Electric $ 1 100,000,000 100 100 PSNH $ 1 100,000,000 301 301 WMECO $ 25 1,072,471 434,653 434,653 As of both June 30, 2017 and December 31, 2016 , there were 16,992,594 Eversource common shares held as treasury shares. As of both June 30, 2017 and December 31, 2016 , Eversource common shares outstanding were 316,885,808 . COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS Dividends on the preferred stock of CL&P and NSTAR Electric totaled $1.9 million for both of the three months ended June 30, 2017 and 2016 , and $3.8 million for both of the six months ended June 30, 2017 and 2016 . These dividends were presented as Net Income Attributable to Noncontrolling Interests on the Eversource statements of income. Noncontrolling Interest – Preferred Stock of Subsidiaries on the Eversource balance sheets totaled $155.6 million as of June 30, 2017 and December 31, 2016 . On the Eversource balance sheets, Common Shareholders' Equity was fully attributable to the parent and Noncontrolling Interest – Preferred Stock of Subsidiaries was fully attributable to the noncontrolling interest.

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic EPS is computed based upon the weighted average number of common shares outstanding during each period. Diluted EPS is computed on the basis of the weighted average number of common shares outstanding plus the potential dilutive effect of certain share-based compensation awards as if they were converted into common shares. The dilutive effect of unvested RSU and performance share awards and unexercised stock options is calculated using the treasury stock method. RSU and performance share awards are included in basic weighted average common shares outstanding as of the date that all necessary vesting conditions have been satisfied. For the three and six months ended June 30, 2017 and 2016 , there were no antidilutive share awards excluded from the computation of diluted EPS. The following table sets forth the components of basic and diluted EPS: Eversource (Millions of Dollars, except share information) For the Three Months Ended For the Six Months Ended June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Net Income Attributable to Common Shareholders $ 230.7 $ 203.6 $ 490.2 $ 447.8 Weighted Average Common Shares Outstanding: Basic 317,391,365 317,785,495 317,427,258 317,651,319 Dilutive Effect 555,829 691,204 608,606 827,557 Diluted 317,947,194 318,476,699 318,035,864 318,478,876 Basic and Diluted EPS $ 0.72 $ 0.64 $ 1.54 $ 1.41

SEGMENT INFORMATION

SEGMENT INFORMATION	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION Presentation: Eversource is organized among 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' services, the sources of operating revenues and expenses and the regulatory environment in which each segment operates. These reportable segments represent 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 Eversource parent from its subsidiaries and intercompany interest income, both of which are eliminated in consolidation, and interest expense related to the debt of Eversource parent, 2) the revenues and expenses of Eversource Service, most of which are eliminated in consolidation, 3) the operations of CYAPC and YAEC, and 4) the results of other unregulated subsidiaries, which are not part of its core business. In addition, Other in the tables below includes Eversource parent's equity ownership interests in certain natural gas pipeline projects owned by Enbridge, Inc., the Bay State Wind project, a renewable energy investment fund, and two companies that transmit hydroelectricity imported from the Hydro-Quebec system in Canada. In the ordinary course of business, Yankee Gas and NSTAR Gas purchase natural gas transmission services from the Enbridge, Inc. natural gas pipeline projects described above. These affiliate transaction costs total approximately $62.5 million annually and are classified as Purchased Power, Fuel and Transmission on the Eversource statements of income. 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, AFUDC related to equity funds, and the capitalized portions of pension expense. 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 of company resources. Each of Eversource's subsidiaries, including CL&P, NSTAR Electric, PSNH and WMECO, has one reportable segment. Eversource's operating segments and reporting units are consistent with its reportable business segments. Eversource's segment information is as follows: For the Three Months Ended June 30, 2017 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 1,275.9 $ 186.0 $ 324.6 $ 217.0 $ (240.7 ) $ 1,762.8 Depreciation and Amortization (105.4 ) (17.9 ) (51.4 ) (7.9 ) 0.5 (182.1 ) Other Operating Expenses (925.3 ) (150.0 ) (94.9 ) (195.9 ) 241.1 (1,125.0 ) Operating Income 245.2 18.1 178.3 13.2 0.9 455.7 Interest Expense (49.4 ) (10.9 ) (28.9 ) (21.6 ) 3.5 (107.3 ) Other Income, Net 2.5 0.1 6.8 257.6 (245.5 ) 21.5 Net Income Attributable to Common Shareholders $ 121.9 $ 4.5 $ 96.4 $ 249.0 $ (241.1 ) $ 230.7 For the Six Months Ended June 30, 2017 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 2,677.0 $ 589.6 $ 641.5 $ 453.4 $ (493.6 ) $ 3,867.9 Depreciation and Amortization (235.2 ) (39.6 ) (102.0 ) (17.2 ) 1.1 (392.9 ) Other Operating Expenses (1,967.3 ) (439.6 ) (184.8 ) (412.5 ) 493.9 (2,510.3 ) Operating Income 474.5 110.4 354.7 23.7 1.4 964.7 Interest Expense (97.6 ) (21.5 ) (57.0 ) (41.3 ) 6.6 (210.8 ) Other Income, Net 7.4 0.4 11.7 586.5 (570.9 ) 35.1 Net Income Attributable to Common Shareholders $ 236.0 $ 55.3 $ 190.6 $ 571.2 $ (562.9 ) $ 490.2 Cash Flows Used for Investments in Plant $ 515.0 $ 139.7 $ 415.6 $ 76.7 $ — $ 1,147.0 For the Three Months Ended June 30, 2016 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 1,303.1 $ 180.4 $ 302.5 $ 211.1 $ (229.9 ) $ 1,767.2 Depreciation and Amortization (98.4 ) (16.8 ) (45.6 ) (7.5 ) 0.5 (167.8 ) Other Operating Expenses (994.4 ) (141.1 ) (82.5 ) (188.1 ) 230.1 (1,176.0 ) Operating Income 210.3 22.5 174.4 15.5 0.7 423.4 Interest Expense (47.6 ) (10.4 ) (27.4 ) (16.6 ) 1.5 (100.5 ) Other Income, Net 6.3 0.1 5.3 219.0 (222.6 ) 8.1 Net Income Attributable to Common Shareholders $ 102.8 $ 8.0 $ 92.5 $ 220.7 $ (220.4 ) $ 203.6 For the Six Months Ended June 30, 2016 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 2,739.2 $ 523.0 $ 585.8 $ 425.3 $ (450.5 ) $ 3,822.8 Depreciation and Amortization (226.1 ) (32.7 ) (90.7 ) (14.4 ) 1.1 (362.8 ) Other Operating Expenses (2,083.3 ) (374.5 ) (155.5 ) (385.4 ) 450.7 (2,548.0 ) Operating Income 429.8 115.8 339.6 25.5 1.3 912.0 Interest Expense (95.6 ) (20.5 ) (55.3 ) (30.7 ) 3.4 (198.7 ) Other Income/(Loss), Net 6.3 (0.2 ) 7.9 524.4 (528.4 ) 10.0 Net Income Attributable to Common Shareholders $ 211.3 $ 58.9 $ 178.2 $ 523.1 $ (523.7 ) $ 447.8 Cash Flows Used for Investments in Plant $ 362.0 $ 105.0 $ 349.1 $ 53.1 $ — $ 869.2 The following table summarizes Eversource's segmented total assets: Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Other Eliminations Total As of June 30, 2017 $ 18,663.7 $ 3,337.0 $ 9,003.4 $ 14,657.1 $ (13,002.4 ) $ 32,658.8 As of December 31, 2016 18,367.5 3,303.8 8,751.5 14,493.1 (12,862.7 ) 32,053.2

SUMMARY OF SIGNIFICANT ACCOUN21

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	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 regulated utility subsidiaries consist of CL&P, NSTAR Electric, PSNH, WMECO, Yankee Gas and NSTAR Gas. Eversource provides energy delivery service to approximately 3.7 million electric and natural gas customers through these six regulated utilities in Connecticut, Massachusetts and New Hampshire. On June 2, 2017, Eversource announced that it had entered into an agreement to acquire Aquarion Water Company ("Aquarion") from Macquarie Infrastructure Partners for $1.675 billion , consisting of approximately $880 million in cash and $795 million of assumed Aquarion debt. The transaction requires approval from PURA, the DPU, the NHPUC, the Maine PUC, and the Federal Communications Commission, and is also subject to a review under the Hart-Scott-Rodino Act. On June 29, 2017, Eversource and Aquarion filed joint applications with regulatory agencies in Connecticut, Massachusetts, New Hampshire and Maine requesting approval of the transaction. The transaction is expected to close by December 31, 2017. The unaudited condensed consolidated financial statements of Eversource, NSTAR Electric and PSNH include the accounts of each of 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 Combined Notes to Financial Statements included in Item 8, "Financial Statements and Supplementary Data," of the Eversource 2016 Form 10-K, which was filed with the SEC. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The financial statements contain, in the opinion of management, all adjustments (including normal, recurring adjustments) necessary to present fairly Eversource's, CL&P's, NSTAR Electric's, PSNH's and WMECO's financial position as of June 30, 2017 and December 31, 2016 , the results of operations and comprehensive income for the three and six months ended June 30, 2017 and 2016 , and the cash flows for the six months ended June 30, 2017 and 2016 . The results of operations and comprehensive income for the three and six months ended June 30, 2017 and 2016 and the cash flows for the six months ended June 30, 2017 and 2016 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 assets) 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 differences 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
Accounting Standards	Accounting Standards Accounting Standards Issued but Not Yet Effective: In May 2014, the Financial Accounting Standards Board ("FASB") issued an Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers , which amends existing revenue recognition guidance and is required to be applied retrospectively (either to each reporting period presented or cumulatively at the date of initial application). The Company is evaluating the requirements and potential impacts of ASU 2014-09 and will implement the standard in the first quarter of 2018 cumulatively at the date of initial application. While the guidance continues to be interpreted on an industry specific level, implementation of the ASU is not currently expected to have a material effect on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO. In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Liabilities , which is required to be implemented in the first quarter of 2018. The ASU will remove the available-for-sale designation for equity securities, whereby changes in fair value are recorded in accumulated other comprehensive income within shareholders' equity, and will require changes in fair value of all equity securities to be recorded in earnings beginning on January 1, 2018, with the unrealized gain or loss on available-for-sale equity securities as of that date reclassified to retained earnings as a cumulative effect of adoption. The fair value of available-for-sale equity securities subject to this guidance as of June 30, 2017 was approximately $49 million . The remaining available-for-sale equity securities included in marketable securities on the balance sheet are held in nuclear decommissioning trusts and are subject to regulatory accounting treatment and will not be impacted by this guidance. Implementation of the ASU for other financial instruments is not expected to have a material impact on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO. In February 2016, the FASB issued ASU 2016-02, Leases , which changes existing lease accounting guidance and is required to be applied in the first quarter of 2019, with earlier application permitted. The ASU is required to be implemented for leases beginning on the date of initial application. For prior periods presented, leases are required to be recognized and measured using a modified retrospective approach. The Company is reviewing the requirements of ASU 2016-02, including balance sheet recognition of leases previously deemed operating leases, and expects to implement the ASU in the first quarter of 2019. In March 2017, the FASB issued ASU 2017-07, Compensation – Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , required to be implemented in the first quarter of 2018. The ASU requires separate presentation of service cost from other components of net pension and PBOP costs, with the other components presented as non-operating income and not subject to capitalization. The Company is assessing the impacts of the ASU on the financial statements of Eversource, CL&P, NSTAR Electric, PSNH and WMECO; however, implementation of the ASU is not expected to have a material impact on the net income of Eversource, CL&P, NSTAR Electric, PSNH and WMECO.
Provision for Uncollectible Accounts	Provision for Uncollectible Accounts Eversource, including CL&P, NSTAR Electric, PSNH and WMECO, presents its receivables at estimated net realizable value by maintaining a provision for uncollectible accounts. This provision is determined based upon a variety of judgments and factors, including the application of an estimated uncollectible percentage to each receivable aging category. The estimate is based upon historical collection and write-off experience and management's assessment of collectability from customers. Management continuously assesses the collectability of receivables and adjusts collectability estimates based on actual experience. Receivable balances are written off against the provision for uncollectible accounts when the customer accounts are terminated and these balances are deemed to be uncollectible. The PURA allows CL&P and Yankee Gas to accelerate the recovery of accounts receivable balances attributable to qualified customers under financial or medical duress (uncollectible hardship accounts receivable) outstanding for greater than 180 days and 90 days, respectively. The DPU allows WMECO and NSTAR Gas also to recover in rates, amounts associated with certain uncollectible hardship accounts receivable. Certain of NSTAR Electric's uncollectible hardship accounts receivable are expected to be recovered in future rates, similar to WMECO and NSTAR Gas. These uncollectible customer account balances are included in Regulatory Assets or Other Long-Term Assets on the balance sheets.
Fair Value Measurements	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 guidance is also applied to valuations of the investments used to calculate the funded status of pension and PBOP plans, the nonrecurring fair value measurements of nonfinancial assets such as goodwill and AROs, and the estimated fair value of preferred stock and long-term debt. Fair Value Hierarchy: In measuring fair value, Eversource uses observable 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.
Other Income, Net	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 income/(loss) related to equity method investments. Investment income/(loss) primarily relates to debt and equity securities held in trust.
Other Taxes	Other Taxes Gross receipts taxes levied by the state of Connecticut are collected by CL&P and Yankee Gas from their respective customers. As agents for state and local governments, Eversource's companies that serve customers in Connecticut and Massachusetts collect certain sales taxes that are recorded on a net basis with no impact on the statements of income.

SUMMARY OF SIGNIFICANT ACCOUN22

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The total provision for uncollectible accounts and for uncollectible hardship accounts, which is included in the total provision, is included in Receivables, Net on the balance sheets, and was as follows: Total Provision for Uncollectible Accounts Uncollectible Hardship (Millions of Dollars) As of June 30, 2017 As of December 31, 2016 As of June 30, 2017 As of December 31, 2016 Eversource $ 199.0 $ 200.6 $ 124.5 $ 119.9 CL&P 77.5 86.4 64.5 67.7 NSTAR Electric 54.5 54.8 30.7 26.2 PSNH 11.0 9.9 — — WMECO 16.4 15.5 10.6 9.9
State Of Connecticut Gross Earnings Taxes	These gross receipts taxes are shown separately with collections in Operating Revenues and with payments in Taxes Other Than Income Taxes on the statements of income as follows: For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Eversource $ 35.7 $ 37.5 $ 77.9 $ 79.8 CL&P 31.8 33.6 65.7 69.6
Schedule of Supplemental Cash Flow Information	Non-cash investing activities include plant additions included in Accounts Payable as follows: (Millions of Dollars) As of June 30, 2017 As of June 30, 2016 Eversource $ 172.0 $ 186.3 CL&P 85.9 59.5 NSTAR Electric 29.5 38.5 PSNH 20.2 31.1 WMECO 10.6 14.6

REGULATORY ACCOUNTING (Tables)

REGULATORY ACCOUNTING (Tables)	6 Months Ended
	Jun. 30, 2017
Regulated Operations [Abstract]
Schedule of Regulatory Assets	The components of regulatory assets were as follows: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Benefit Costs $ 1,833.6 $ 1,817.8 Derivative Liabilities 398.1 423.3 Income Taxes, Net 652.5 644.5 Storm Restoration Costs 352.9 385.3 Goodwill-related 454.2 464.4 Regulatory Tracker Mechanisms 584.3 576.6 Asset Retirement Obligations 103.0 99.3 Other Regulatory Assets 72.8 115.1 Total Regulatory Assets 4,451.4 4,526.3 Less: Current Portion 870.4 887.6 Total Long-Term Regulatory Assets $ 3,581.0 $ 3,638.7 As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Benefit Costs $ 423.5 $ 445.6 $ 189.7 $ 86.4 $ 429.3 $ 438.6 $ 184.2 $ 86.7 Derivative Liabilities 394.8 2.3 — — 420.5 2.8 — — Income Taxes, Net 440.7 91.2 22.4 31.2 437.0 89.7 24.2 30.8 Storm Restoration Costs 210.3 115.3 12.9 14.4 239.8 112.5 17.1 15.9 Goodwill-related — 389.9 — — — 398.7 — — Regulatory Tracker Mechanisms 153.0 240.7 125.7 50.5 123.9 257.3 104.5 46.7 Asset Retirement Obligations 34.5 33.2 16.6 4.4 33.2 31.9 16.2 4.2 Other Regulatory Assets 32.7 16.1 14.7 5.3 43.4 15.6 16.5 7.1 Total Regulatory Assets 1,689.5 1,334.3 382.0 192.2 1,727.1 1,347.1 362.7 191.4 Less: Current Portion 346.5 270.2 132.4 67.3 335.5 289.4 117.2 64.1 Total Long-Term Regulatory Assets $ 1,343.0 $ 1,064.1 $ 249.6 $ 124.9 $ 1,391.6 $ 1,057.7 $ 245.5 $ 127.3
Schedule of Regulatory Liabilities	The components of regulatory liabilities were as follows: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Cost of Removal $ 474.4 $ 459.7 Benefit Costs 129.5 136.2 Regulatory Tracker Mechanisms 176.3 145.3 AFUDC - Transmission 65.6 65.8 Other Regulatory Liabilities 36.8 42.1 Total Regulatory Liabilities 882.6 849.1 Less: Current Portion 185.9 146.8 Total Long-Term Regulatory Liabilities $ 696.7 $ 702.3 As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Cost of Removal $ 43.4 $ 277.4 $ 42.8 $ 12.4 $ 38.8 $ 271.6 $ 44.1 $ 8.6 Benefit Costs — 109.4 — — — 113.1 — — Regulatory Tracker Mechanisms 47.5 48.4 11.7 10.9 37.2 63.7 10.7 14.7 AFUDC - Transmission 49.5 7.4 — 8.7 50.2 6.9 — 8.7 Other Regulatory Liabilities 23.7 0.3 3.0 — 21.0 0.2 2.7 0.1 Total Regulatory Liabilities 164.1 442.9 57.5 32.0 147.2 455.5 57.5 32.1 Less: Current Portion 62.2 48.4 13.7 11.1 47.1 63.7 12.7 14.9 Total Long-Term Regulatory Liabilities $ 101.9 $ 394.5 $ 43.8 $ 20.9 $ 100.1 $ 391.8 $ 44.8 $ 17.2

PROPERTY, PLANT AND EQUIPMENT24

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION (Tables)	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Public Utility Property, Plant, and Equipment	The following tables summarize utility property, plant and equipment by asset category: Eversource As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Distribution - Electric $ 14,012.6 $ 13,716.9 Distribution - Natural Gas 3,094.3 3,010.4 Transmission - Electric 8,817.6 8,517.4 Generation 1,215.4 1,224.2 Electric and Natural Gas Utility 27,139.9 26,468.9 Other (1) 594.0 591.6 Property, Plant and Equipment, Gross 27,733.9 27,060.5 Less: Accumulated Depreciation Electric and Natural Gas Utility (6,706.6 ) (6,480.4 ) Other (262.8 ) (242.0 ) Total Accumulated Depreciation (6,969.4 ) (6,722.4 ) Property, Plant and Equipment, Net 20,764.5 20,338.1 Construction Work in Progress (2) 1,307.0 1,012.4 Total Property, Plant and Equipment, Net $ 22,071.5 $ 21,350.5 (1) These assets are primarily comprised of building improvements, computer software, hardware and equipment at Eversource Service. (2) As of June 30, 2017 , the total CWIP related to NPT was approximately $190 million . As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Distribution $ 5,717.1 $ 5,453.3 $ 2,018.6 $ 863.6 $ 5,562.9 $ 5,402.3 $ 1,949.8 $ 841.9 Transmission 4,016.4 2,530.3 1,103.1 1,119.4 3,912.9 2,435.8 1,059.3 1,061.1 Generation — — 1,179.4 36.0 — — 1,188.2 36.0 Property, Plant and Equipment, Gross 9,733.5 7,983.6 4,301.1 2,019.0 9,475.8 7,838.1 4,197.3 1,939.0 Less: Accumulated Depreciation (2,156.7 ) (2,104.2 ) (1,290.1 ) (352.0 ) (2,082.4 ) (2,025.4 ) (1,254.7 ) (338.8 ) Property, Plant and Equipment, Net 7,576.8 5,879.4 3,011.0 1,667.0 7,393.4 5,812.7 2,942.6 1,600.2 Construction Work in Progress 363.6 309.1 107.5 52.8 239.0 239.1 96.7 78.1 Total Property, Plant and Equipment, Net $ 7,940.4 $ 6,188.5 $ 3,118.5 $ 1,719.8 $ 7,632.4 $ 6,051.8 $ 3,039.3 $ 1,678.3

DERIVATIVE INSTRUMENTS (Tables)

DERIVATIVE INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table presents the gross fair values of contracts, categorized by risk type, and the net amounts recorded as current or long-term derivative assets or liabilities: As of June 30, 2017 As of December 31, 2016 (Millions of Dollars) Commodity Supply and Price Risk Management Netting (1) Net Amount Recorded as a Derivative Commodity Supply and Price Risk Netting (1) Net Amount Recorded as a Derivative Current Derivative Assets: Level 2: Eversource $ — $ — $ — $ 6.0 $ — $ 6.0 Level 3: Eversource, CL&P 11.2 (7.7 ) 3.5 13.9 (9.4 ) 4.5 Long-Term Derivative Assets: Level 2: Eversource $ — $ — $ — $ 0.3 $ (0.1 ) $ 0.2 Level 3: Eversource, CL&P 76.0 (8.0 ) 68.0 77.3 (11.7 ) 65.6 Current Derivative Liabilities: Level 2: Eversource $ (1.1 ) $ 0.1 $ (1.0 ) $ — $ — $ — Level 3: Eversource (66.5 ) — (66.5 ) (79.7 ) — (79.7 ) CL&P (64.3 ) — (64.3 ) (77.8 ) — (77.8 ) NSTAR Electric (2.2 ) — (2.2 ) (1.9 ) — (1.9 ) Long-Term Derivative Liabilities: Level 3: Eversource $ (402.1 ) $ — $ (402.1 ) $ (413.7 ) $ — $ (413.7 ) CL&P (402.0 ) — (402.0 ) (412.8 ) — (412.8 ) NSTAR Electric (0.1 ) — (0.1 ) (0.9 ) — (0.9 ) (1) Amounts represent derivative 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.
Fair Value Inputs, Liabilities, Quantitative Information	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 June 30, 2017 As of December 31, 2016 Range Period Covered Range Period Covered Capacity Prices: Eversource, CL&P $ 5.00 — 8.70 per kW-Month 2021 - 2026 $ 5.50 — 8.70 per kW-Month 2020 - 2026 Forward Reserve: Eversource, CL&P $ 1.40 — 2.00 per kW-Month 2017 - 2024 $ 1.40 — 2.00 per kW-Month 2017 - 2024 REC Prices: Eversource, NSTAR Electric $ 26.00 — 27.50 per REC 2017 - 2018 $ 24.00 — 29.00 per REC 2017 - 2018
Rollforward Of Net Derivative Asset Liabilities Valued Using Unobservable Inputs	The following table presents 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 June 30, 2017 2016 (Millions of Dollars) Eversource CL&P NSTAR Electric Eversource CL&P NSTAR Derivatives, Net: Fair Value as of Beginning of Period $ (416.0 ) $ (413.5 ) $ (2.5 ) $ (387.7 ) $ (385.1 ) $ (2.6 ) Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities (3.0 ) (0.6 ) (2.4 ) (46.6 ) (46.8 ) 0.2 Settlements 21.9 19.3 2.6 21.7 20.6 1.1 Fair Value as of End of Period $ (397.1 ) $ (394.8 ) $ (2.3 ) $ (412.6 ) $ (411.3 ) $ (1.3 ) For the Six Months Ended June 30, 2017 2016 (Millions of Dollars) Eversource CL&P NSTAR Eversource CL&P NSTAR Derivatives, Net: Fair Value as of Beginning of Period $ (423.3 ) $ (420.5 ) $ (2.8 ) $ (380.9 ) $ (380.8 ) $ (0.1 ) Net Realized/Unrealized Losses Included in Regulatory Assets and Liabilities (18.4 ) (15.2 ) (3.2 ) (76.6 ) (72.2 ) (4.4 ) Settlements 44.6 40.9 3.7 44.9 41.7 3.2 Fair Value as of End of Period $ (397.1 ) $ (394.8 ) $ (2.3 ) $ (412.6 ) $ (411.3 ) $ (1.3 )

MARKETABLE SECURITIES (Tables)

MARKETABLE SECURITIES (Tables)	6 Months Ended
	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following is a summary of available-for-sale securities, which are recorded at fair value and are included in current and long-term Marketable Securities on the balance sheets. As of June 30, 2017 As of December 31, 2016 Eversource (Millions of Dollars) Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Amortized Cost Pre-Tax Unrealized Gains Pre-Tax Unrealized Losses Fair Value Debt Securities $ 290.3 $ 4.7 $ (0.5 ) $ 294.5 $ 296.2 $ 1.1 $ (2.1 ) $ 295.2 Equity Securities 202.1 83.2 — 285.3 203.3 62.3 (1.2 ) 264.4
Investments Classified by Contractual Maturity Date	As of June 30, 2017 , the contractual maturities of available-for-sale debt securities were as follows: Eversource (Millions of Dollars) Amortized Cost Fair Value Less than one year (1) $ 53.0 $ 52.9 One to five years 52.6 53.4 Six to ten years 54.7 56.3 Greater than ten years 130.0 131.9 Total Debt Securities $ 290.3 $ 294.5 (1) Amounts in the Less than one year category include securities in the CYAPC and YAEC nuclear decommissioning trusts, which are restricted and are classified in long-term Marketable Securities on the balance sheets.
Fair Value on a Recurring Basis	The following table presents the marketable securities recorded at fair value on a recurring basis by the level in which they are classified within the fair value hierarchy: Eversource (Millions of Dollars) As of June 30, 2017 As of December 31, 2016 Level 1: Mutual Funds and Equities $ 285.3 $ 274.0 Money Market Funds 29.7 54.8 Total Level 1 $ 315.0 $ 328.8 Level 2: U.S. Government Issued Debt Securities (Agency and Treasury) $ 53.9 $ 63.0 Corporate Debt Securities 67.8 41.1 Asset-Backed Debt Securities 18.6 18.5 Municipal Bonds 113.1 107.5 Other Fixed Income Securities 11.4 10.3 Total Level 2 $ 264.8 $ 240.4 Total Marketable Securities $ 579.8 $ 569.2

PENSION BENEFITS AND POSTRETI27

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS (Tables)	6 Months Ended
	Jun. 30, 2017
Postemployment Benefits [Abstract]
Schedule of Net Benefit Costs	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 portions of pension, SERP and PBOP amounts, are included in Operations and Maintenance expense on the statements of income. Capitalized amounts relate to employees working on capital projects and are included in Property, Plant and Equipment, Net on the balance sheets. Pension, SERP and PBOP expense reflected in the statements of cash flows for CL&P, NSTAR Electric, PSNH and WMECO does not include the intercompany allocations or the corresponding capitalized portion, as these amounts are cash settled on a short-term basis. Pension and SERP Eversource For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Service Cost $ 17.4 $ 18.7 $ 36.4 $ 37.9 Interest Cost 47.2 46.4 93.5 92.8 Expected Return on Pension Plan Assets (83.5 ) (79.5 ) (167.0 ) (159.1 ) Actuarial Loss 33.9 31.3 67.5 63.0 Prior Service Cost 1.1 0.9 2.0 1.8 Total Net Periodic Benefit Expense $ 16.1 $ 17.8 $ 32.4 $ 36.4 Capitalized Pension Expense $ 5.5 $ 5.4 $ 10.9 $ 11.4 PBOP Eversource For the Three Months Ended For the Six Months Ended (Millions of Dollars) June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Service Cost $ 2.4 $ 3.1 $ 4.7 $ 6.3 Interest Cost 6.3 9.4 13.5 19.0 Expected Return on Plan Assets (16.0 ) (15.7 ) (31.9 ) (31.5 ) Actuarial Loss 2.5 0.9 4.6 2.1 Prior Service Credit (5.3 ) — (10.7 ) (0.1 ) Total Net Periodic Benefit Income $ (10.1 ) $ (2.3 ) $ (19.8 ) $ (4.2 ) Capitalized PBOP Income $ (4.9 ) $ (1.0 ) $ (9.5 ) $ (1.9 ) Pension and SERP For the Three Months Ended June 30, 2017 For the Three Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 4.6 $ 3.1 $ 2.4 $ 0.7 $ 4.6 $ 3.3 $ 2.5 $ 0.8 Interest Cost 10.5 8.6 5.3 2.1 10.2 8.5 5.1 2.1 Expected Return on Pension Plan Assets (17.8 ) (17.5 ) (10.0 ) (4.4 ) (18.0 ) (16.9 ) (9.6 ) (4.4 ) Actuarial Loss 6.8 8.9 3.0 1.5 6.3 8.7 2.6 1.3 Prior Service Cost 0.4 0.1 0.1 0.1 0.4 — 0.1 0.1 Total Net Periodic Benefit Expense/(Income) $ 4.5 $ 3.2 $ 0.8 $ — $ 3.5 $ 3.6 $ 0.7 $ (0.1 ) Intercompany Allocations $ 2.4 $ 1.8 $ 0.8 $ 0.5 $ 3.5 $ 2.2 $ 1.0 $ 0.6 Capitalized Pension Expense $ 2.4 $ 1.9 $ 0.4 $ 0.1 $ 2.2 $ 2.0 $ 0.4 $ 0.1 Pension and SERP For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 9.3 $ 6.3 $ 4.9 $ 1.5 $ 9.6 $ 6.7 $ 5.0 $ 1.6 Interest Cost 20.9 17.0 10.5 4.2 21.0 16.8 10.3 4.2 Expected Return on Pension Plan Assets (36.0 ) (35.1 ) (19.9 ) (8.9 ) (36.2 ) (33.8 ) (19.3 ) (8.8 ) Actuarial Loss 13.9 17.5 5.8 3.0 13.0 17.0 4.9 2.8 Prior Service Cost 0.7 0.2 0.2 0.2 0.8 — 0.2 0.2 Total Net Periodic Benefit Expense $ 8.8 $ 5.9 $ 1.5 $ — $ 8.2 $ 6.7 $ 1.1 $ — Intercompany Allocations $ 5.0 $ 3.7 $ 1.7 $ 0.9 $ 6.8 $ 4.5 $ 2.0 $ 1.2 Capitalized Pension Expense $ 4.9 $ 3.5 $ 0.7 $ 0.2 $ 4.9 $ 3.7 $ 0.7 $ 0.2 PBOP For the Three Months Ended June 30, 2017 For the Three Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 0.5 $ 0.3 $ 0.3 $ 0.1 $ 0.4 $ 1.0 $ 0.3 $ 0.1 Interest Cost 1.2 1.7 0.7 0.3 1.3 3.8 0.7 0.3 Expected Return on Plan Assets (2.4 ) (6.6 ) (1.3 ) (0.6 ) (2.5 ) (6.4 ) (1.4 ) (0.6 ) Actuarial Loss 0.3 0.8 0.2 — 0.3 0.3 0.1 — Prior Service Cost/(Credit) 0.3 (4.3 ) 0.1 — — — — — Total Net Periodic Benefit Income $ (0.1 ) $ (8.1 ) $ — $ (0.2 ) $ (0.5 ) $ (1.3 ) $ (0.3 ) $ (0.2 ) Intercompany Allocations $ (0.1 ) $ (0.2 ) $ (0.1 ) $ — $ 0.2 $ 0.1 $ — $ — Capitalized PBOP Income $ (0.1 ) $ (4.1 ) $ — $ (0.1 ) $ (0.2 ) $ (0.6 ) $ (0.1 ) $ (0.1 ) PBOP For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 (Millions of Dollars) CL&P NSTAR Electric PSNH WMECO CL&P NSTAR Electric PSNH WMECO Service Cost $ 0.9 $ 0.7 $ 0.6 $ 0.2 $ 0.9 $ 1.8 $ 0.6 $ 0.2 Interest Cost 2.7 3.8 1.5 0.5 2.7 7.8 1.5 0.5 Expected Return on Plan Assets (4.8 ) (13.2 ) (2.7 ) (1.1 ) (5.1 ) (12.7 ) (2.8 ) (1.1 ) Actuarial Loss 0.5 1.7 0.3 — 0.5 0.5 0.2 — Prior Service Cost/(Credit) 0.5 (8.6 ) 0.3 0.1 — — — — Total Net Periodic Benefit Income $ (0.2 ) $ (15.6 ) $ — $ (0.3 ) $ (1.0 ) $ (2.6 ) $ (0.5 ) $ (0.4 ) Intercompany Allocations $ (0.4 ) $ (0.5 ) $ (0.2 ) $ (0.1 ) $ 0.3 $ 0.1 $ — $ 0.1 Capitalized PBOP Income $ (0.2 ) $ (7.9 ) $ — $ (0.2 ) $ (0.5 ) $ (1.1 ) $ (0.1 ) $ (0.2 )

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Environmental Loss Contingencies by Site	The number of environmental sites and related reserves for which remediation or long-term monitoring, preliminary site work or site assessment is being performed are as follows: As of June 30, 2017 As of December 31, 2016 Number of Sites Reserve (in millions) Number of Sites Reserve (in millions) Eversource 58 $ 57.7 61 $ 65.8 CL&P 14 5.1 14 4.9 NSTAR Electric 11 2.2 13 3.2 PSNH 11 5.7 11 5.3 WMECO 4 0.7 4 0.6
Schedule of Guarantor Obligations	The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries to external parties, as of June 30, 2017 : Company Description Maximum Exposure (in millions) Expiration Dates On behalf of subsidiaries: Eversource Gas Transmission LLC Access Northeast Project Capital Contributions Guaranty (1) $ 185.1 2021 Various Surety Bonds (2) 40.1 2017 - 2018 Eversource Service and Rocky River Realty Company Lease Payments for Vehicles and Real Estate 8.5 2019 - 2024 (1) Eversource parent issued a declining balance guaranty on behalf of its subsidiary, Eversource Gas Transmission LLC, to guarantee the payment of the subsidiary's capital contributions for its investment in the Access Northeast project. The guaranty decreases as capital contributions are made. The guaranty will expire upon the earlier of the full performance of the guaranteed obligations or December 31, 2021. (2) Surety bond expiration dates reflect termination dates, the majority of which will be renewed or extended. Certain surety bonds contain credit ratings triggers that would require Eversource parent to post collateral in the event that the unsecured debt credit ratings of Eversource parent are downgraded.
Schedule of Complaints and Base ROE	A summary of the four separate complaints and the base ROEs pertinent to those complaints are as follows: Complaint 15-Month Time Period of Complaint (Beginning as of Complaint Filing Date) Original Base ROE Authorized by FERC at Time of Complaint Filing Date (1) Base ROE Subsequently Authorized by FERC for First Complaint Period and also Effective from October 16, 2014 through April 14, 2017 (1) Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions) FERC ALJ Recommendation of Base ROE on Second and Third Complaints (Issued March 22, 2016) First 10/1/2011 - 12/31/2012 11.14% 10.57% $— (2) N/A Second 12/27/2012 - 3/26/2014 11.14% N/A 39.1 (3) 9.59% Third 7/31/2014 - 10/30/2015 11.14% 10.57% — 10.90% Fourth 4/29/2016 - 7/28/2017 10.57% 10.57% — N/A (1) The billed ROE (base plus incentives) between October 1, 2011 and October 15, 2014 was within a range of 11.14 percent to 13.1 percent . On October 16, 2014, the FERC set the incentive cap at 11.74 percent for the first complaint period and also effective from October 16, 2014 through April 14, 2017, at which time the Court vacated this FERC order. (2) CL&P, NSTAR Electric, PSNH and WMECO have refunded all amounts associated with the first complaint period, totaling $38.9 million (pre-tax and excluding interest) at Eversource (including $22.4 million at CL&P, $8.4 million at NSTAR Electric, $2.8 million at PSNH, and $5.3 million at WMECO), reflecting both the base ROE and incentive cap prescribed by the FERC order. (3) The reserve represents the difference between the ROEs billed during the second complaint period and a 10.57 percent base ROE and 11.74 percent incentive cap. The reserve was $21.4 million for CL&P, $8.5 million for NSTAR Electric, $3.1 million for PSNH, and $6.1 million for WMECO as of June 30, 2017 .

PSNH GENERATION ASSET SALE - (T

PSNH GENERATION ASSET SALE - (Tables)	6 Months Ended
	Jun. 30, 2017
Regulated Operations [Abstract]
Schedule of Generation Assets and Liabilities	As of June 30, 2017 , PSNH's generation assets were as follows: (Millions of Dollars) Gross Plant $ 1,183.3 Accumulated Depreciation (564.1 ) Net Plant 619.2 Fuel 94.6 Materials and Supplies 36.3 Emission Allowances 19.5 Total Generation Assets $ 769.6

FAIR VALUE OF FINANCIAL INSTR30

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	Carrying amounts and estimated fair values are as follows: As of June 30, 2017 As of December 31, 2016 Eversource (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Preferred Stock Not Subject to Mandatory Redemption $ 155.6 $ 158.4 $ 155.6 $ 158.3 Long-Term Debt 10,382.9 10,935.8 9,603.2 9,980.5 CL&P NSTAR Electric PSNH WMECO (Millions of Dollars) Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value Carrying Amount Fair Value As of June 30, 2017: Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 115.0 $ 43.0 $ 43.4 $ — $ — $ — $ — Long-Term Debt 2,913.5 3,247.3 2,425.9 2,605.9 1,072.3 1,122.3 566.3 602.8 As of December 31, 2016: Preferred Stock Not Subject to Mandatory Redemption $ 116.2 $ 114.7 $ 43.0 $ 43.6 $ — $ — $ — $ — Long-Term Debt 2,766.0 3,049.6 2,078.1 2,201.6 1,072.0 1,109.7 566.5 589.0

ACCUMULATED OTHER COMPREHENSI31

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Tables)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in accumulated other comprehensive income/(loss) by component, net of tax, is as follows: For the Six Months Ended June 30, 2017 For the Six Months Ended June 30, 2016 Qualified Unrealized Qualified Unrealized Cash Flow Gains Cash Flow Gains/(Losses) Eversource (Millions of Dollars) Hedging on Marketable Defined Hedging on Marketable Defined Instruments Securities Benefit Plans Total Instruments Securities Benefit Plans Total Balance as of Beginning of Period $ (8.2 ) $ 0.4 $ (57.5 ) $ (65.3 ) $ (10.3 ) $ (1.9 ) $ (54.6 ) $ (66.8 ) OCI Before Reclassifications — 2.6 (3.5 ) (0.9 ) — 1.3 (2.6 ) (1.3 ) Amounts Reclassified from AOCL 1.1 — 2.2 3.3 1.1 — 1.6 2.7 Net OCI 1.1 2.6 (1.3 ) 2.4 1.1 1.3 (1.0 ) 1.4 Balance as of End of Period $ (7.1 ) $ 3.0 $ (58.8 ) $ (62.9 ) $ (9.2 ) $ (0.6 ) $ (55.6 ) $ (65.4 )

COMMON SHARES (Tables)

COMMON SHARES (Tables)	6 Months Ended
	Jun. 30, 2017
Equity [Abstract]
Schedule of Stock by Class	The following table sets forth the Eversource parent common shares and the shares of common stock of CL&P, NSTAR Electric, PSNH and WMECO that were authorized and issued, as well as the respective per share par values: Shares Authorized as of June 30, 2017 and Issued as of Par Value December 31, 2016 June 30, 2017 December 31, 2016 Eversource $ 5 380,000,000 333,878,402 333,878,402 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

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the components of basic and diluted EPS: Eversource (Millions of Dollars, except share information) For the Three Months Ended For the Six Months Ended June 30, 2017 June 30, 2016 June 30, 2017 June 30, 2016 Net Income Attributable to Common Shareholders $ 230.7 $ 203.6 $ 490.2 $ 447.8 Weighted Average Common Shares Outstanding: Basic 317,391,365 317,785,495 317,427,258 317,651,319 Dilutive Effect 555,829 691,204 608,606 827,557 Diluted 317,947,194 318,476,699 318,035,864 318,478,876 Basic and Diluted EPS $ 0.72 $ 0.64 $ 1.54 $ 1.41

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Eversource's segment information is as follows: For the Three Months Ended June 30, 2017 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 1,275.9 $ 186.0 $ 324.6 $ 217.0 $ (240.7 ) $ 1,762.8 Depreciation and Amortization (105.4 ) (17.9 ) (51.4 ) (7.9 ) 0.5 (182.1 ) Other Operating Expenses (925.3 ) (150.0 ) (94.9 ) (195.9 ) 241.1 (1,125.0 ) Operating Income 245.2 18.1 178.3 13.2 0.9 455.7 Interest Expense (49.4 ) (10.9 ) (28.9 ) (21.6 ) 3.5 (107.3 ) Other Income, Net 2.5 0.1 6.8 257.6 (245.5 ) 21.5 Net Income Attributable to Common Shareholders $ 121.9 $ 4.5 $ 96.4 $ 249.0 $ (241.1 ) $ 230.7 For the Six Months Ended June 30, 2017 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 2,677.0 $ 589.6 $ 641.5 $ 453.4 $ (493.6 ) $ 3,867.9 Depreciation and Amortization (235.2 ) (39.6 ) (102.0 ) (17.2 ) 1.1 (392.9 ) Other Operating Expenses (1,967.3 ) (439.6 ) (184.8 ) (412.5 ) 493.9 (2,510.3 ) Operating Income 474.5 110.4 354.7 23.7 1.4 964.7 Interest Expense (97.6 ) (21.5 ) (57.0 ) (41.3 ) 6.6 (210.8 ) Other Income, Net 7.4 0.4 11.7 586.5 (570.9 ) 35.1 Net Income Attributable to Common Shareholders $ 236.0 $ 55.3 $ 190.6 $ 571.2 $ (562.9 ) $ 490.2 Cash Flows Used for Investments in Plant $ 515.0 $ 139.7 $ 415.6 $ 76.7 $ — $ 1,147.0 For the Three Months Ended June 30, 2016 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 1,303.1 $ 180.4 $ 302.5 $ 211.1 $ (229.9 ) $ 1,767.2 Depreciation and Amortization (98.4 ) (16.8 ) (45.6 ) (7.5 ) 0.5 (167.8 ) Other Operating Expenses (994.4 ) (141.1 ) (82.5 ) (188.1 ) 230.1 (1,176.0 ) Operating Income 210.3 22.5 174.4 15.5 0.7 423.4 Interest Expense (47.6 ) (10.4 ) (27.4 ) (16.6 ) 1.5 (100.5 ) Other Income, Net 6.3 0.1 5.3 219.0 (222.6 ) 8.1 Net Income Attributable to Common Shareholders $ 102.8 $ 8.0 $ 92.5 $ 220.7 $ (220.4 ) $ 203.6 For the Six Months Ended June 30, 2016 Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Transmission Other Eliminations Total Operating Revenues $ 2,739.2 $ 523.0 $ 585.8 $ 425.3 $ (450.5 ) $ 3,822.8 Depreciation and Amortization (226.1 ) (32.7 ) (90.7 ) (14.4 ) 1.1 (362.8 ) Other Operating Expenses (2,083.3 ) (374.5 ) (155.5 ) (385.4 ) 450.7 (2,548.0 ) Operating Income 429.8 115.8 339.6 25.5 1.3 912.0 Interest Expense (95.6 ) (20.5 ) (55.3 ) (30.7 ) 3.4 (198.7 ) Other Income/(Loss), Net 6.3 (0.2 ) 7.9 524.4 (528.4 ) 10.0 Net Income Attributable to Common Shareholders $ 211.3 $ 58.9 $ 178.2 $ 523.1 $ (523.7 ) $ 447.8 Cash Flows Used for Investments in Plant $ 362.0 $ 105.0 $ 349.1 $ 53.1 $ — $ 869.2 The following table summarizes Eversource's segmented total assets: Eversource (Millions of Dollars) Electric Distribution Natural Gas Distribution Electric Other Eliminations Total As of June 30, 2017 $ 18,663.7 $ 3,337.0 $ 9,003.4 $ 14,657.1 $ (13,002.4 ) $ 32,658.8 As of December 31, 2016 18,367.5 3,303.8 8,751.5 14,493.1 (12,862.7 ) 32,053.2

SUMMARY OF SIGNIFICANT ACCOUN35

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Basis of Presentation (Details) customer in Millions, $ in Millions	Jun. 02, 2017USD ($)	Jun. 30, 2017customerutility
Schedule of Equity Method Investments [Line Items]
Number of electric and natural gas customers | customer		3.7
Connecticut, Massachusetts and New Hampshire [Member]
Schedule of Equity Method Investments [Line Items]
Number of regulated utilities | utility		6
Aquarion Water Company [Member]
Schedule of Equity Method Investments [Line Items]
Amount involved in acquisition of Aquarion	$ 1,675
Cash paid to acquire Aquarion	880
Liability assumed in acquisition of Aquarion	$ 795

SUMMARY OF SIGNIFICANT ACCOUN36

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Accounting Standards (Details) $ in Millions	Jun. 30, 2017USD ($)
Accounting Policies [Abstract]
Available for sale securities subject to new accounting guidance	$ 49

SUMMARY OF SIGNIFICANT ACCOUN37

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts Narrative (Details)	6 Months Ended
	Jun. 30, 2017
Maximum [Member] | The Connecticut Light And Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period of accounts receivable recoverable under financial or medical duress	180 days
Minimum [Member] | Yankee Gas Services Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period of accounts receivable recoverable under financial or medical duress	90 days

SUMMARY OF SIGNIFICANT ACCOUN38

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	$ 199	$ 200.6
Uncollectible Hardship	124.5	119.9
The Connecticut Light And Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	77.5	86.4
Uncollectible Hardship	64.5	67.7
NSTAR Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	54.5	54.8
Uncollectible Hardship	30.7	26.2
Public Service Company Of New Hampshire [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	11	9.9
Uncollectible Hardship	0	0
Western Massachusetts Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Provision for Uncollectible Accounts	16.4	15.5
Uncollectible Hardship	$ 10.6	$ 9.9

SUMMARY OF SIGNIFICANT ACCOUN39

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Income, Net Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Income, Net [Line Items]
Other Income/(Loss), Net	$ 21,543	$ 8,038	$ 35,120	$ 10,049
Equity Method Investments
Other Income, Net [Line Items]
Other Income/(Loss), Net	$ 13,300		$ 17,900

SUMMARY OF SIGNIFICANT ACCOUN40

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Gross Tax Receipts [Line Items]
Excise and sales taxes	$ 35.7	$ 37.5	$ 77.9	$ 79.8
The Connecticut Light And Power Company [Member]
Schedule of Gross Tax Receipts [Line Items]
Excise and sales taxes	$ 31.8	$ 33.6	$ 65.7	$ 69.6

SUMMARY OF SIGNIFICANT ACCOUN41

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Supplemental Cash Flow (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Schedule of Supplemental Cash Flow [Line Items]
Capital expenditures incurred but not yet paid	$ 172	$ 186.3
The Connecticut Light And Power Company [Member]
Schedule of Supplemental Cash Flow [Line Items]
Capital expenditures incurred but not yet paid	85.9	59.5
NSTAR Electric Company [Member]
Schedule of Supplemental Cash Flow [Line Items]
Capital expenditures incurred but not yet paid	29.5	38.5
Public Service Company Of New Hampshire [Member]
Schedule of Supplemental Cash Flow [Line Items]
Capital expenditures incurred but not yet paid	20.2	31.1
Western Massachusetts Electric Company [Member]
Schedule of Supplemental Cash Flow [Line Items]
Capital expenditures incurred but not yet paid	$ 10.6	$ 14.6

REGULATORY ACCOUNTING - Compone

REGULATORY ACCOUNTING - Components of Regulatory Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 4,451,400	$ 4,526,300
Less: Current Portion	870,393	887,625
Total Long-Term Regulatory Assets	3,580,981	3,638,688
Benefit Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	1,833,600	1,817,800
Derivative Liabilities [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	398,100	423,300
Income Taxes, Net [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	652,500	644,500
Storm Restoration Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	352,900	385,300
Goodwill-related [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	454,200	464,400
Regulatory Tracker Mechanisms [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	584,300	576,600
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	103,000	99,300
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	72,800	115,100
The Connecticut Light And Power Company [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	1,689,500	1,727,100
Less: Current Portion	346,520	335,526
Total Long-Term Regulatory Assets	1,343,011	1,391,564
The Connecticut Light And Power Company [Member] | Benefit Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	423,500	429,300
The Connecticut Light And Power Company [Member] | Derivative Liabilities [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	394,800	420,500
The Connecticut Light And Power Company [Member] | Income Taxes, Net [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	440,700	437,000
The Connecticut Light And Power Company [Member] | Storm Restoration Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	210,300	239,800
The Connecticut Light And Power Company [Member] | Goodwill-related [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
The Connecticut Light And Power Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	153,000	123,900
The Connecticut Light And Power Company [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	34,500	33,200
The Connecticut Light And Power Company [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	32,700	43,400
NSTAR Electric Company [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	1,334,300	1,347,100
Less: Current Portion	270,230	289,400
Total Long-Term Regulatory Assets	1,064,099	1,057,746
NSTAR Electric Company [Member] | Benefit Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	445,600	438,600
NSTAR Electric Company [Member] | Derivative Liabilities [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	2,300	2,800
NSTAR Electric Company [Member] | Income Taxes, Net [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	91,200	89,700
NSTAR Electric Company [Member] | Storm Restoration Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	115,300	112,500
NSTAR Electric Company [Member] | Goodwill-related [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	389,900	398,700
NSTAR Electric Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	240,700	257,300
NSTAR Electric Company [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	33,200	31,900
NSTAR Electric Company [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	16,100	15,600
Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	382,000	362,700
Less: Current Portion	132,424	117,240
Total Long-Term Regulatory Assets	249,612	245,525
Public Service Company Of New Hampshire [Member] | Benefit Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	189,700	184,200
Public Service Company Of New Hampshire [Member] | Derivative Liabilities [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Public Service Company Of New Hampshire [Member] | Income Taxes, Net [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	22,400	24,200
Public Service Company Of New Hampshire [Member] | Storm Restoration Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	12,900	17,100
Public Service Company Of New Hampshire [Member] | Goodwill-related [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Public Service Company Of New Hampshire [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	125,700	104,500
Public Service Company Of New Hampshire [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	16,600	16,200
Public Service Company Of New Hampshire [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	14,700	16,500
Western Massachusetts Electric Company [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	192,200	191,400
Less: Current Portion	67,310	64,123
Total Long-Term Regulatory Assets	124,899	127,291
Western Massachusetts Electric Company [Member] | Benefit Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	86,400	86,700
Western Massachusetts Electric Company [Member] | Derivative Liabilities [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Western Massachusetts Electric Company [Member] | Income Taxes, Net [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	31,200	30,800
Western Massachusetts Electric Company [Member] | Storm Restoration Costs [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	14,400	15,900
Western Massachusetts Electric Company [Member] | Goodwill-related [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
Western Massachusetts Electric Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	50,500	46,700
Western Massachusetts Electric Company [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	4,400	4,200
Western Massachusetts Electric Company [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 5,300	$ 7,100

REGULATORY ACCOUNTING - Regulat

REGULATORY ACCOUNTING - Regulatory Costs in Other Long-Term Assets (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	$ 103	$ 86.3
The Connecticut Light And Power Company [Member]
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	3.5	5.9
NSTAR Electric Company [Member]
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	40.1	35
Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	16.4	8.2
Western Massachusetts Electric Company [Member]
Regulatory Assets [Line Items]
Amount of regulatory costs not yet approved	$ 24.3	$ 20.1

REGULATORY ACCOUNTING - Compo44

REGULATORY ACCOUNTING - Components of Regulatory Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 882,600	$ 849,100
Less: Current Portion	185,930	146,787
Total Long-Term Regulatory Liabilities	696,740	702,255
Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	474,400	459,700
Benefit Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	129,500	136,200
Regulatory Tracker Mechanisms [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	176,300	145,300
AFUDC - Transmission [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	65,600	65,800
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	36,800	42,100
The Connecticut Light And Power Company [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	164,100	147,200
Less: Current Portion	62,195	47,055
Total Long-Term Regulatory Liabilities	101,863	100,138
The Connecticut Light And Power Company [Member] | Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	43,400	38,800
The Connecticut Light And Power Company [Member] | Benefit Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
The Connecticut Light And Power Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	47,500	37,200
The Connecticut Light And Power Company [Member] | AFUDC - Transmission [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	49,500	50,200
The Connecticut Light And Power Company [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	23,700	21,000
NSTAR Electric Company [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	442,900	455,500
Less: Current Portion	48,350	63,653
Total Long-Term Regulatory Liabilities	394,527	391,823
NSTAR Electric Company [Member] | Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	277,400	271,600
NSTAR Electric Company [Member] | Benefit Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	109,400	113,100
NSTAR Electric Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	48,400	63,700
NSTAR Electric Company [Member] | AFUDC - Transmission [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	7,400	6,900
NSTAR Electric Company [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	300	200
Public Service Company Of New Hampshire [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	57,500	57,500
Less: Current Portion	13,696	12,659
Total Long-Term Regulatory Liabilities	43,845	44,779
Public Service Company Of New Hampshire [Member] | Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	42,800	44,100
Public Service Company Of New Hampshire [Member] | Benefit Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Public Service Company Of New Hampshire [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	11,700	10,700
Public Service Company Of New Hampshire [Member] | AFUDC - Transmission [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Public Service Company Of New Hampshire [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	3,000	2,700
Western Massachusetts Electric Company [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	32,000	32,100
Less: Current Portion	11,062	14,888
Total Long-Term Regulatory Liabilities	20,887	17,227
Western Massachusetts Electric Company [Member] | Cost of Removal [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	12,400	8,600
Western Massachusetts Electric Company [Member] | Benefit Costs [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
Western Massachusetts Electric Company [Member] | Regulatory Tracker Mechanisms [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	10,900	14,700
Western Massachusetts Electric Company [Member] | AFUDC - Transmission [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	8,700	8,700
Western Massachusetts Electric Company [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 0	$ 100

PROPERTY, PLANT AND EQUIPMENT45

PROPERTY, PLANT AND EQUIPMENT AND ACCUMULATED DEPRECIATION - Investment in Utility Property, plant and equipment by asset (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	$ 14,012,600	$ 13,716,900
Distribution - Natural Gas	3,094,300	3,010,400
Transmission	8,817,600	8,517,400
Generation	1,215,400	1,224,200
Electric and Natural Gas Utility	27,139,900	26,468,900
Other	594,000	591,600
Property, Plant and Equipment, Gross	27,733,900	27,060,500
Less: Accumulated Depreciation
Electric and Natural Gas Utility	(6,706,600)	(6,480,400)
Other	(262,800)	(242,000)
Total Accumulated Depreciation	(6,969,400)	(6,722,400)
Property, Plant and Equipment, Net	20,764,500	20,338,100
Construction Work in Progress	1,307,000	1,012,400
Net Plant	22,071,496	21,350,510
Construction work in progress related to NPT	190,000
The Connecticut Light And Power Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	5,717,100	5,562,900
Transmission	4,016,400	3,912,900
Generation	0	0
Property, Plant and Equipment, Gross	9,733,500	9,475,800
Less: Accumulated Depreciation
Total Accumulated Depreciation	(2,156,700)	(2,082,400)
Property, Plant and Equipment, Net	7,576,800	7,393,400
Construction Work in Progress	363,600	239,000
Net Plant	7,940,398	7,632,392
NSTAR Electric Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	5,453,300	5,402,300
Transmission	2,530,300	2,435,800
Generation	0	0
Property, Plant and Equipment, Gross	7,983,600	7,838,100
Less: Accumulated Depreciation
Total Accumulated Depreciation	(2,104,200)	(2,025,400)
Property, Plant and Equipment, Net	5,879,400	5,812,700
Construction Work in Progress	309,100	239,100
Net Plant	6,188,535	6,051,835
Public Service Company Of New Hampshire [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	2,018,600	1,949,800
Transmission	1,103,100	1,059,300
Generation	1,179,400	1,188,200
Property, Plant and Equipment, Gross	4,301,100	4,197,300
Less: Accumulated Depreciation
Total Accumulated Depreciation	(1,290,100)	(1,254,700)
Property, Plant and Equipment, Net	3,011,000	2,942,600
Construction Work in Progress	107,500	96,700
Net Plant	3,118,456	3,039,313
Western Massachusetts Electric Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Distribution - Electric	863,600	841,900
Transmission	1,119,400	1,061,100
Generation	36,000	36,000
Property, Plant and Equipment, Gross	2,019,000	1,939,000
Less: Accumulated Depreciation
Total Accumulated Depreciation	(352,000)	(338,800)
Property, Plant and Equipment, Net	1,667,000	1,600,200
Construction Work in Progress	52,800	78,100
Net Plant	$ 1,719,824	$ 1,678,262

DERIVATIVE INSTRUMENTS - Gross

DERIVATIVE INSTRUMENTS - Gross Fair Value of Contracts (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current Derivative Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	$ 0	$ 6
Netting	0	0
Net Amount Recorded as a Derivative	0	6
Current Derivative Assets [Member] | Eversource and The Connecticut Light And Power Company [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	11.2	13.9
Netting	(7.7)	(9.4)
Net Amount Recorded as a Derivative	3.5	4.5
Long-term Derivative Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	0	0.3
Netting	0	(0.1)
Net Amount Recorded as a Derivative	0	0.2
Long-term Derivative Assets [Member] | Eversource and The Connecticut Light And Power Company [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract]
Commodity Supply and Price Risk Management	76	77.3
Netting	(8)	(11.7)
Net Amount Recorded as a Derivative	68	65.6
Current Derivative Liabilities [Member] | Fair Value, Inputs, Level 2 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(1.1)	0
Netting	0.1	0
Net Amount Recorded as a Derivative	(1)	0
Current Derivative Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(66.5)	(79.7)
Netting	0	0
Net Amount Recorded as a Derivative	(66.5)	(79.7)
Current Derivative Liabilities [Member] | The Connecticut Light And Power Company [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(64.3)	(77.8)
Netting	0	0
Net Amount Recorded as a Derivative	(64.3)	(77.8)
Current Derivative Liabilities [Member] | NSTAR Electric Company [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(2.2)	(1.9)
Netting	0	0
Net Amount Recorded as a Derivative	(2.2)	(1.9)
Long-Term Derivative Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(402.1)	(413.7)
Netting	0	0
Net Amount Recorded as a Derivative	(402.1)	(413.7)
Long-Term Derivative Liabilities [Member] | The Connecticut Light And Power Company [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(402)	(412.8)
Netting	0	0
Net Amount Recorded as a Derivative	(402)	(412.8)
Long-Term Derivative Liabilities [Member] | NSTAR Electric Company [Member] | Fair Value, Inputs, Level 3 [Member]
Current and Long-Term Derivative Liabilities
Commodity Supply and Price Risk Management	(0.1)	(0.9)
Netting	0	0
Net Amount Recorded as a Derivative	$ (0.1)	$ (0.9)

DERIVATIVE INSTRUMENTS - Deriva

DERIVATIVE INSTRUMENTS - Derivative Contracts at Fair Value (Details) MWh in Millions, MMBTU in Millions, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)MMBTUMWhMW	Jun. 30, 2016USD ($)	Dec. 31, 2016MMBTU
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts by United Illuminated Company			20.00%
Amount of power to be purchased under capacity-related contract (up to) | MW			787
Amount of natural gas to be purchased under futures contracts | MMBTU			6.3		9.2
Losses deferred as regulatory costs | $	$ (4.4)	$ (42.9)	$ (30.9)	$ (74.4)
The Connecticut Light And Power Company [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of costs or benefits borne under capacity-related contracts			80.00%
Amount of energy to be purchased under renewable energy contract (in mwh) | MWh			0.1
NSTAR Electric Company [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of power to be purchased under capacity-related contract (up to) | MW			35
Amount of energy to be purchased under renewable energy contract (in mwh) | MWh			0.1

DERIVATIVE INSTRUMENTS - Unobse

DERIVATIVE INSTRUMENTS - Unobservable Inputs Utilized (Details) - Fair Value, Inputs, Level 3 [Member] - $ / KWmo	Jun. 30, 2017	Dec. 31, 2016
Eversource and The Connecticut Light And Power Company [Member] | Minimum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Capacity Prices (in USDPerKiloWattMonth)	5	5.50
Forward Reserve (in USDPerKiloWattMonth)	1.40	1.40
Eversource and The Connecticut Light And Power Company [Member] | Maximum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Capacity Prices (in USDPerKiloWattMonth)	8.70	8.70
Forward Reserve (in USDPerKiloWattMonth)	2	2
Eversource and NSTAR Electric Company [Member] | Minimum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
REC Prices (in USDPerKiloWattMonth)	26	24
Eversource and NSTAR Electric Company [Member] | Maximum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
REC Prices (in USDPerKiloWattMonth)	27.50	29

DERIVATIVE INSTRUMENTS - Unob49

DERIVATIVE INSTRUMENTS - Unobservable Inputs Narrative (Details) - Fair Value, Inputs, Level 3 [Member]	6 Months Ended
	Jun. 30, 2017
Minimum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts	2.00%
Maximum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Percentage of exit price premiums related to derivative contracts	19.00%

DERIVATIVE INSTRUMENTS - Deri50

DERIVATIVE INSTRUMENTS - Derivative Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivatives, Net [Rollforward]
Fair Value as of Beginning of Period	$ (416)	$ (387.7)	$ (423.3)	$ (380.9)
Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities	(3)	(46.6)	(18.4)	(76.6)
Settlements	21.9	21.7	44.6	44.9
Fair Value as of End of Period	(397.1)	(412.6)	(397.1)	(412.6)
The Connecticut Light And Power Company [Member]
Derivatives, Net [Rollforward]
Fair Value as of Beginning of Period	(413.5)	(385.1)	(420.5)	(380.8)
Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities	(0.6)	(46.8)	(15.2)	(72.2)
Settlements	19.3	20.6	40.9	41.7
Fair Value as of End of Period	(394.8)	(411.3)	(394.8)	(411.3)
NSTAR Electric Company [Member]
Derivatives, Net [Rollforward]
Fair Value as of Beginning of Period	(2.5)	(2.6)	(2.8)	(0.1)
Net Realized/Unrealized Gains/(Losses) Included in Regulatory Assets and Liabilities	(2.4)	0.2	(3.2)	(4.4)
Settlements	2.6	1.1	3.7	3.2
Fair Value as of End of Period	$ (2.3)	$ (1.3)	$ (2.3)	$ (1.3)

MARKETABLE SECURITIES - Trading

MARKETABLE SECURITIES - Trading Securities (Details) - Fair Value, Inputs, Level 1 [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair value of securities under fair value option			$ 9.6
Other Income [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Net gain (loss) under fair value option	$ 0.2	$ 0.5

MARKETABLE SECURITIES - Schedul

MARKETABLE SECURITIES - Schedule of Available for Sale Securities (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 290.3	$ 296.2
Pre-Tax Unrealized Gains	4.7	1.1
Pre-Tax Unrealized Losses	(0.5)	(2.1)
Fair Value	294.5	295.2
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	202.1	203.3
Pre-Tax Unrealized Gains	83.2	62.3
Pre-Tax Unrealized Losses	0	(1.2)
Fair Value	$ 285.3	$ 264.4

MARKETABLE SECURITIES - Availab

MARKETABLE SECURITIES - Available for Sale Securities Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Debt, equity and marketable securities held in nuclear decommissioning trust	$ 485.9	$ 466.7

MARKETABLE SECURITIES - Sched54

MARKETABLE SECURITIES - Schedule of Contractual Maturities (Details) $ in Millions	Jun. 30, 2017USD ($)
Amortized Cost
Less than one year	$ 53
One to five years	52.6
Six to ten years	54.7
Greater than ten years	130
Total Debt Securities	290.3
Fair Value
Less than one year	52.9
One to five years	53.4
Six to ten years	56.3
Greater than ten years	131.9
Total Debt Securities	$ 294.5

MARKETABLE SECURITIES - Sched55

MARKETABLE SECURITIES - Schedule of Fair Value Measurements (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	$ 579.8	$ 569.2
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	315	328.8
Fair Value, Inputs, Level 1 [Member] | Mutual Funds and Equities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	285.3	274
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	29.7	54.8
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	264.8	240.4
Fair Value, Inputs, Level 2 [Member] | U.S. Government Issued Debt Securities (Agency and Treasury) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	53.9	63
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	67.8	41.1
Fair Value, Inputs, Level 2 [Member] | Asset-Backed Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	18.6	18.5
Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	113.1	107.5
Fair Value, Inputs, Level 2 [Member] | Other Fixed Income Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities recorded at fair value on a recurring basis	$ 11.4	$ 10.3

SHORT-TERM AND LONG-TERM DEBT -

SHORT-TERM AND LONG-TERM DEBT - Commercial Paper Programs and Credit Agreements (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Eversource Parent [Member]
Line of Credit Facility [Line Items]
Amount outstanding during period	$ 0	$ 0
Eversource Parent [Member] | Commercial Paper [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	1,450,000,000
Short-term borrowings outstanding	937,500,000	1,000,000,000
Remaining borrowing capacity	$ 512,500,000	$ 428,000,000
Weighted average interest rate (as a percentage)	1.34%	0.88%
Eversource Parent [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,450,000,000
Debt instrument term	5 years
The Connecticut Light And Power Company [Member]
Line of Credit Facility [Line Items]
Notes payable to Eversource Parent	$ 101,100,000	$ 80,100,000
Public Service Company Of New Hampshire [Member]
Line of Credit Facility [Line Items]
Notes payable to Eversource Parent	194,100,000	160,900,000
Western Massachusetts Electric Company [Member]
Line of Credit Facility [Line Items]
Notes payable to Eversource Parent	68,700,000	51,000,000
NSTAR Electric Company [Member]
Line of Credit Facility [Line Items]
Amount outstanding during period	0	0
NSTAR Electric Company [Member] | Commercial Paper [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	450,000,000
Short-term borrowings outstanding	0	126,500,000
Remaining borrowing capacity	450,000,000	$ 323,500,000
Weighted average interest rate (as a percentage)		0.71%
NSTAR Electric Company [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 450,000,000
Debt instrument term	5 years

SHORT-TERM AND LONG-TERM DEBT57

SHORT-TERM AND LONG-TERM DEBT - Long-Term Debt Issuances (Details) - Senior Notes [Member] - USD ($)	May 31, 2017	Mar. 31, 2017
Eversource Parent [Member] | Series K Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 300,000,000
Interest rate stated percentage		2.75%
The Connecticut Light And Power Company [Member] | 2017 Series A First and Refunding Mortgage Bonds Due 2027 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 300,000,000
Interest rate stated percentage		3.20%
NSTAR Electric Company [Member] | Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 350,000,000
Interest rate stated percentage	3.20%

SHORT-TERM AND LONG-TERM DEBT58

SHORT-TERM AND LONG-TERM DEBT - Long-Term Debt Repayments (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Mar. 31, 2017	Jun. 30, 2017	Jun. 30, 2016
Debt Instrument [Line Items]
Repayments of debt		$ 150,000	$ 200,000
The Connecticut Light And Power Company [Member]
Debt Instrument [Line Items]
Repayments of debt		$ 150,000	$ 0
2007 Series A First and Refunding Mortgage Bonds [Member] | Senior Notes [Member] | The Connecticut Light And Power Company [Member]
Debt Instrument [Line Items]
Repayments of debt	$ 150,000
Interest rate stated percentage	5.375%

SHORT-TERM AND LONG - Long-Term

SHORT-TERM AND LONG - Long-Term Debt Issuance Authorization (Details) - Senior Notes [Member] - USD ($) $ in Millions	Mar. 30, 2017	Jan. 04, 2017
The Connecticut Light And Power Company [Member]
Debt Instrument [Line Items]
Amount of debt authorized (up to)		$ 1,325
NSTAR Electric Company [Member]
Debt Instrument [Line Items]
Amount of debt authorized (up to)	$ 700

PENSION BENEFITS AND POSTRETI60

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Pension Plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Prior service credit as a result of remeasurement	$ 5.3	$ 10.7

PENSION BENEFITS AND POSTRETI61

PENSION BENEFITS AND POSTRETIREMENT BENEFITS OTHER THAN PENSIONS - Components of Periodic Benefit Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	$ 17.4	$ 18.7	$ 36.4	$ 37.9
Interest Cost	47.2	46.4	93.5	92.8
Expected Return on Pension Plan Assets	(83.5)	(79.5)	(167)	(159.1)
Actuarial Loss	33.9	31.3	67.5	63
Prior Service Cost/(Credit)	1.1	0.9	2	1.8
Total Net Periodic Benefit Income	16.1	17.8	32.4	36.4
Capitalized PBOP Income/Expense	5.5	5.4	10.9	11.4
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	2.4	3.1	4.7	6.3
Interest Cost	6.3	9.4	13.5	19
Expected Return on Pension Plan Assets	(16)	(15.7)	(31.9)	(31.5)
Actuarial Loss	2.5	0.9	4.6	2.1
Prior Service Cost/(Credit)	(5.3)	0	(10.7)	(0.1)
Total Net Periodic Benefit Income	(10.1)	(2.3)	(19.8)	(4.2)
Capitalized PBOP Income/Expense	(4.9)	(1)	(9.5)	(1.9)
The Connecticut Light And Power Company [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	4.6	4.6	9.3	9.6
Interest Cost	10.5	10.2	20.9	21
Expected Return on Pension Plan Assets	(17.8)	(18)	(36)	(36.2)
Actuarial Loss	6.8	6.3	13.9	13
Prior Service Cost/(Credit)	0.4	0.4	0.7	0.8
Total Net Periodic Benefit Income	4.5	3.5	8.8	8.2
Intercompany Allocations	2.4	3.5	5	6.8
Capitalized PBOP Income/Expense	2.4	2.2	4.9	4.9
The Connecticut Light And Power Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.5	0.4	0.9	0.9
Interest Cost	1.2	1.3	2.7	2.7
Expected Return on Pension Plan Assets	(2.4)	(2.5)	(4.8)	(5.1)
Actuarial Loss	0.3	0.3	0.5	0.5
Prior Service Cost/(Credit)	0.3	0	0.5	0
Total Net Periodic Benefit Income	(0.1)	(0.5)	(0.2)	(1)
Intercompany Allocations	(0.1)	0.2	(0.4)	0.3
Capitalized PBOP Income/Expense	(0.1)	(0.2)	(0.2)	(0.5)
NSTAR Electric Company [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	3.1	3.3	6.3	6.7
Interest Cost	8.6	8.5	17	16.8
Expected Return on Pension Plan Assets	(17.5)	(16.9)	(35.1)	(33.8)
Actuarial Loss	8.9	8.7	17.5	17
Prior Service Cost/(Credit)	0.1	0	0.2	0
Total Net Periodic Benefit Income	3.2	3.6	5.9	6.7
Intercompany Allocations	1.8	2.2	3.7	4.5
Capitalized PBOP Income/Expense	1.9	2	3.5	3.7
NSTAR Electric Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.3	1	0.7	1.8
Interest Cost	1.7	3.8	3.8	7.8
Expected Return on Pension Plan Assets	(6.6)	(6.4)	(13.2)	(12.7)
Actuarial Loss	0.8	0.3	1.7	0.5
Prior Service Cost/(Credit)	(4.3)	0	(8.6)	0
Total Net Periodic Benefit Income	(8.1)	(1.3)	(15.6)	(2.6)
Intercompany Allocations	(0.2)	0.1	(0.5)	0.1
Capitalized PBOP Income/Expense	(4.1)	(0.6)	(7.9)	(1.1)
Public Service Company Of New Hampshire [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	2.4	2.5	4.9	5
Interest Cost	5.3	5.1	10.5	10.3
Expected Return on Pension Plan Assets	(10)	(9.6)	(19.9)	(19.3)
Actuarial Loss	3	2.6	5.8	4.9
Prior Service Cost/(Credit)	0.1	0.1	0.2	0.2
Total Net Periodic Benefit Income	0.8	0.7	1.5	1.1
Intercompany Allocations	0.8	1	1.7	2
Capitalized PBOP Income/Expense	0.4	0.4	0.7	0.7
Public Service Company Of New Hampshire [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.3	0.3	0.6	0.6
Interest Cost	0.7	0.7	1.5	1.5
Expected Return on Pension Plan Assets	(1.3)	(1.4)	(2.7)	(2.8)
Actuarial Loss	0.2	0.1	0.3	0.2
Prior Service Cost/(Credit)	0.1	0	0.3	0
Total Net Periodic Benefit Income	0	(0.3)	0	(0.5)
Intercompany Allocations	(0.1)	0	(0.2)	0
Capitalized PBOP Income/Expense	0	(0.1)	0	(0.1)
Western Massachusetts Electric Company [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.7	0.8	1.5	1.6
Interest Cost	2.1	2.1	4.2	4.2
Expected Return on Pension Plan Assets	(4.4)	(4.4)	(8.9)	(8.8)
Actuarial Loss	1.5	1.3	3	2.8
Prior Service Cost/(Credit)	0.1	0.1	0.2	0.2
Total Net Periodic Benefit Income	0	(0.1)	0	0
Intercompany Allocations	0.5	0.6	0.9	1.2
Capitalized PBOP Income/Expense	0.1	0.1	0.2	0.2
Western Massachusetts Electric Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost	0.1	0.1	0.2	0.2
Interest Cost	0.3	0.3	0.5	0.5
Expected Return on Pension Plan Assets	(0.6)	(0.6)	(1.1)	(1.1)
Actuarial Loss	0	0	0	0
Prior Service Cost/(Credit)	0	0	0.1	0
Total Net Periodic Benefit Income	(0.2)	(0.2)	(0.3)	(0.4)
Intercompany Allocations	0	0	(0.1)	0.1
Capitalized PBOP Income/Expense	$ (0.1)	$ (0.1)	$ (0.2)	$ (0.2)

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Schedule of Environmental Matters (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)site	Dec. 31, 2016USD ($)site
Site Contingency [Line Items]
Number of Sites | site	58	61
Reserve | $	$ 57.7	$ 65.8
The Connecticut Light And Power Company [Member]
Site Contingency [Line Items]
Number of Sites | site	14	14
Reserve | $	$ 5.1	$ 4.9
NSTAR Electric Company [Member]
Site Contingency [Line Items]
Number of Sites | site	11	13
Reserve | $	$ 2.2	$ 3.2
Public Service Company Of New Hampshire [Member]
Site Contingency [Line Items]
Number of Sites | site	11	11
Reserve | $	$ 5.7	$ 5.3
Western Massachusetts Electric Company [Member]
Site Contingency [Line Items]
Number of Sites | site	4	4
Reserve | $	$ 0.7	$ 0.6

COMMITMENTS AND CONTINGENCIES63

COMMITMENTS AND CONTINGENCIES - Environmental Matters Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Site Contingency [Line Items]
Reserve	$ 57.7	$ 65.8
MGP Site accrual [Member]
Site Contingency [Line Items]
Reserve	$ 51.7	$ 59

COMMITMENTS AND CONTINGENCIES64

COMMITMENTS AND CONTINGENCIES - Guarantees and Indemnifications Narrative (Details) $ in Millions	Jun. 30, 2017USD ($)
Guarantee Of Financial Obligations Of Npt [Member]
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure (up to)	$ 25
Guarantee Of Npt Letters Of Credit [Member]
Guarantor Obligations [Line Items]
Guarantor obligations, maximum exposure (up to)	$ 14

COMMITMENTS AND CONTINGENCIES65

COMMITMENTS AND CONTINGENCIES - Schedule of Guarantees and Indemnifications (Details) $ in Millions	Jun. 30, 2017USD ($)
Eversource Gas Transmission LLC [Member]
Loss Contingencies [Line Items]
Maximum Exposure	$ 185.1
Various [Member]
Loss Contingencies [Line Items]
Maximum Exposure	40.1
Eversource Service and Rocky River Realty Company [Member]
Loss Contingencies [Line Items]
Maximum Exposure	$ 8.5

COMMITMENTS AND CONTINGENCIES66

COMMITMENTS AND CONTINGENCIES - FERC ROE Complaints (Details) - USD ($) $ in Millions	Jun. 08, 2017	Apr. 14, 2017	Apr. 29, 2016	Jun. 30, 2017	Mar. 26, 2014	Apr. 14, 2017
FERC ROE First, Second and Third Complaints [Member]
Loss Contingencies [Line Items]
Base ROE percentage challenged by complainants	11.14%			11.14%
Percentage of maximum ROE for any incentive project	13.50%
Period of billing of reinstated ROE				60 days
FERC ROE Complaints [Member]
Loss Contingencies [Line Items]
Period of complaint				15 months
Basis point change				10.00%
Estimate of possible loss for each 10 basis point change to base ROE				$ 3
FERC ROE Fourth Complaint [Member]
Loss Contingencies [Line Items]
Base ROE percentage of complaint period			10.57%
Maximum percentage cap of ROE for incentive projects			11.74%
Loss contingency, estimate of possible earnings impact				$ 0
FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Base ROE percentage challenged by complainants		11.14%		10.57%
Percentage of maximum ROE for any incentive project				11.74%		11.74%
Loss contingency, estimate of possible earnings impact				$ 0
FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Base ROE percentage of complaint period					10.57%
Percentage of maximum ROE for any incentive project					11.74%
Loss contingency, estimate of possible earnings impact				39.1
The Connecticut Light And Power Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				21.4
NSTAR Electric Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				8.5
Public Service Company Of New Hampshire [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				3.1
Western Massachusetts Electric Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible earnings impact				$ 6.1

COMMITMENTS AND CONTINGENCIES67

COMMITMENTS AND CONTINGENCIES - Schedule of Complaints and Base ROEs (Details) - USD ($) $ in Millions	Jun. 08, 2017	Jun. 30, 2017	Jul. 28, 2017	Mar. 26, 2014	Dec. 31, 2012	Oct. 30, 2015	Apr. 14, 2017	Oct. 15, 2014
FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Original Base ROE Authorized by FERC at Time of Complaint (in percentage)					11.14%
Base ROE Subsequently Authorized by FERC for first complaint period and prospectively from October 16, 2014 (in percentage)					10.57%
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		$ 0
Percentage of maximum ROE for any incentive project		11.74%					11.74%
Customer Refund Payments		$ 38.9
FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Original Base ROE Authorized by FERC at Time of Complaint (in percentage)				11.14%
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		39.1
FERC ALJ Recommendation of base ROE on Second and Third Complaints (Issued March 22, 2016) (in percentage)				9.59%
Percentage of maximum ROE for any incentive project				11.74%
FERC ROE Third Complaint [Member]
Loss Contingencies [Line Items]
Original Base ROE Authorized by FERC at Time of Complaint (in percentage)						11.14%
Base ROE Subsequently Authorized by FERC for first complaint period and prospectively from October 16, 2014 (in percentage)						10.57%
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		0
FERC ALJ Recommendation of base ROE on Second and Third Complaints (Issued March 22, 2016) (in percentage)						10.90%
FERC ROE Fourth Complaint [Member]
Loss Contingencies [Line Items]
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		0
FERC ROE First, Second and Third Complaints [Member]
Loss Contingencies [Line Items]
Percentage of maximum ROE for any incentive project	13.50%
The Connecticut Light And Power Company [Member] | FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Customer Refund Payments		22.4
The Connecticut Light And Power Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		21.4
NSTAR Electric Company [Member] | FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Customer Refund Payments		8.4
NSTAR Electric Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		8.5
Public Service Company Of New Hampshire [Member] | FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Customer Refund Payments		2.8
Public Service Company Of New Hampshire [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		3.1
Western Massachusetts Electric Company [Member] | FERC ROE First Complaint [Member]
Loss Contingencies [Line Items]
Customer Refund Payments		5.3
Western Massachusetts Electric Company [Member] | FERC ROE Second Complaint [Member]
Loss Contingencies [Line Items]
Reserve (Pre-Tax and Excluding Interest) as of June 30, 2017 (in millions)		$ 6.1
Minimum [Member] | FERC ROE First, Second and Third Complaints [Member]
Loss Contingencies [Line Items]
Percentage of maximum ROE for any incentive project								11.14%
Maximum [Member] | FERC ROE First, Second and Third Complaints [Member]
Loss Contingencies [Line Items]
Percentage of maximum ROE for any incentive project								13.10%
Subsequent Event [Member] | FERC ROE Fourth Complaint [Member]
Loss Contingencies [Line Items]
Original Base ROE Authorized by FERC at Time of Complaint (in percentage)			10.57%
Base ROE Subsequently Authorized by FERC for first complaint period and prospectively from October 16, 2014 (in percentage)			10.57%

COMMITMENTS AND CONTINGENCIES68

COMMITMENTS AND CONTINGENCIES - Harbor Civil Action (Details) $ in Millions	Jul. 15, 2016MW	Jun. 30, 2017USD ($)
Loss Contingencies [Line Items]
Amount of capacity required for installation of distribution cable (in volts) | MW	0.115
NSTAR Electric Company [Member]
Loss Contingencies [Line Items]
Charge relating to assets previously recognized as capital		$ 4.9
Base rate credit for new cable		$ 17.5
Period of provision of base rate credit		7 years

PSNH GENERATION ASSET SALE - Na

PSNH GENERATION ASSET SALE - Narrative (Details) $ in Thousands	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Jun. 10, 2015USD ($)senator
Regulatory Assets [Line Items]
Equity return related to clean air project forgone			$ 25,000
Other current liabilities	$ 591,222	$ 684,914
Accrued Pension and SERP	1,073,510	1,141,514
Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Other current liabilities	46,415	43,253
Accrued Pension and SERP	101,143	$ 94,652
Electricity Generation Plant, Non-Nuclear [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Number of state senators | senator			2
Accounts payable	30,200
Other current liabilities	17,600
Asset retirement obligation	20,600
Accrued Pension and SERP	$ 23,900

PSNH GENERATION ASSET SALE - PS

PSNH GENERATION ASSET SALE - PSNH Generation Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Gross Plant	$ 27,733,900	$ 27,060,500
Accumulated Depreciation	(6,969,400)	(6,722,400)
Net Plant	22,071,496	21,350,510
Emission Allowances	286,296	328,721
Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Gross Plant	4,301,100	4,197,300
Accumulated Depreciation	(1,290,100)	(1,254,700)
Net Plant	3,118,456	3,039,313
Emission Allowances	150,066	$ 162,354
Electricity Generation Plant, Non-Nuclear [Member] | Public Service Company Of New Hampshire [Member]
Regulatory Assets [Line Items]
Gross Plant	1,183,300
Accumulated Depreciation	(564,100)
Net Plant	619,200
Fuel	94,600
Materials and Supplies	36,300
Emission Allowances	19,500
Total Generation Assets	$ 769,600

FAIR VALUE OF FINANCIAL INSTR71

FAIR VALUE OF FINANCIAL INSTRUMENTS - Carrying Amounts and Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	$ 155,568	$ 155,568
Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	155,600	155,600
Long-Term Debt	10,382,900	9,603,200
Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	158,400	158,300
Long-Term Debt	10,935,800	9,980,500
The Connecticut Light And Power Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,200	116,200
The Connecticut Light And Power Company [Member] | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	116,200	116,200
Long-Term Debt	2,913,500	2,766,000
The Connecticut Light And Power Company [Member] | Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	115,000	114,700
Long-Term Debt	3,247,300	3,049,600
NSTAR Electric Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,000	43,000
NSTAR Electric Company [Member] | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,000	43,000
Long-Term Debt	2,425,900	2,078,100
NSTAR Electric Company [Member] | Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	43,400	43,600
Long-Term Debt	2,605,900	2,201,600
Public Service Company Of New Hampshire [Member] | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	1,072,300	1,072,000
Public Service Company Of New Hampshire [Member] | Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	1,122,300	1,109,700
Western Massachusetts Electric Company [Member] | Carrying Amount | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	566,300	566,500
Western Massachusetts Electric Company [Member] | Fair Value | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Preferred Stock Not Subject to Mandatory Redemption	0	0
Long-Term Debt	$ 602,800	$ 589,000

ACCUMULATED OTHER COMPREHENSI72

ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) - Schedule of Accumulated Other Comprehensive Income (loss) by Component (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
AOCI Attributable to Parent [Roll Forward]
Beginning balance			$ 10,711,734
OCI Before Reclassifications				$ (1,300)
Amounts Reclassified from AOCL				2,700
Net OCI	$ (794)	$ (189)	2,347	1,480
Ending balance	10,885,523		10,885,523
AOCI Attributable to Parent [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance			(65,300)	(66,800)
OCI Before Reclassifications			(900)
Amounts Reclassified from AOCL			3,300
Net OCI			2,400
Ending balance	(62,900)	(65,400)	(62,900)	(65,400)
Qualified Cash Flow Hedging Instruments [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance			(8,200)	(10,300)
OCI Before Reclassifications			0	0
Amounts Reclassified from AOCL			1,100	1,100
Net OCI			1,100	1,100
Ending balance	(7,100)	(9,200)	(7,100)	(9,200)
Unrealized Gains/(Losses) on Marketable Securities [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance			400	(1,900)
OCI Before Reclassifications			2,600	1,300
Amounts Reclassified from AOCL			0	0
Net OCI			2,600	1,300
Ending balance	3,000	(600)	3,000	(600)
Defined Benefit Plans [Member]
AOCI Attributable to Parent [Roll Forward]
Beginning balance			(57,500)	(54,600)
OCI Before Reclassifications			(3,500)	(2,600)
Amounts Reclassified from AOCL			2,200	1,600
Net OCI			(1,300)	(1,000)
Ending balance	$ (58,800)	$ (55,600)	$ (58,800)	$ (55,600)

COMMON SHARES - Schedule of Com

COMMON SHARES - Schedule of Common Shares (Details) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Per Value (in dollars per share)	$ 5	$ 5
Authorized (in shares)	380,000,000	380,000,000
Issued (in shares)	333,878,402	333,878,402
The Connecticut Light And Power Company [Member]
Class of Stock [Line Items]
Per Value (in dollars per share)	$ 10	$ 10
Authorized (in shares)	24,500,000	24,500,000
Issued (in shares)	6,035,205	6,035,205
NSTAR Electric Company [Member]
Class of Stock [Line Items]
Per Value (in dollars per share)	$ 1	$ 1
Authorized (in shares)	100,000,000	100,000,000
Issued (in shares)	100	100
Public Service Company Of New Hampshire [Member]
Class of Stock [Line Items]
Per Value (in dollars per share)	$ 1	$ 1
Authorized (in shares)	100,000,000	100,000,000
Issued (in shares)	301	301
Western Massachusetts Electric Company [Member]
Class of Stock [Line Items]
Per Value (in dollars per share)	$ 25	$ 25
Authorized (in shares)	1,072,471	1,072,471
Issued (in shares)	434,653	434,653

COMMON SHARES - Narrative (Deta

COMMON SHARES - Narrative (Details) - shares	Jun. 30, 2017	Dec. 31, 2016
Equity [Abstract]
Treasury stock (in shares)	16,992,594	16,992,594
Common stock outstanding (in shares)	316,885,808	316,885,808

COMMON SHAREHOLDERS' EQUITY A75

COMMON SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Equity [Abstract]
Net income attributable to noncontrolling interests	$ 1,900	$ 1,900	$ 3,800	$ 3,800
Noncontrolling Interest - Preferred Stock of Subsidiaries	$ 155,568		$ 155,568		$ 155,568

EARNINGS PER SHARE - Narrative

EARNINGS PER SHARE - Narrative (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Antidilutive share awards excluded from computation (in shares)	0	0	0	0

EARNINGS PER SHARE - Schedule o

EARNINGS PER SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net Income Attributable to Common Shareholders	$ 230,749	$ 203,649	$ 490,207	$ 447,803
Weighted Average Common Shares Outstanding:
Basic (in shares)	317,391,365	317,785,495	317,427,258	317,651,319
Dilutive Effect (in shares)	555,829	691,204	608,606	827,557
Diluted (in shares)	317,947,194	318,476,699	318,035,864	318,478,876
Basic and Diluted EPS (in dollars per share)	$ 0.72	$ 0.64	$ 1.54	$ 1.41

SEGMENT INFORMATION - Narrative

SEGMENT INFORMATION - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017USD ($)segmentcompany
Segment Reporting Information [Line Items]
Number of companies that transmit hydro electricity imported from The Hydro-Quebec System in Canada | company	2
Amount of natural gas transmission purchased from Enbridge by Yankee Gas and NSTAR Gas | $	$ 62.5
The Connecticut Light And Power Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	1
NSTAR Electric Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	1
Public Service Company Of New Hampshire [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	1
Western Massachusetts Electric Company [Member]
Segment Reporting Information [Line Items]
Number of reportable segments	1

SEGMENT INFORMATION - Schedule

SEGMENT INFORMATION - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating Revenues	$ 1,762,811	$ 1,767,184	$ 3,867,946	$ 3,822,819
Depreciation and Amortization	(182,100)	(167,800)	(392,900)	(362,800)
Other Operating Expenses	(1,125,000)	(1,176,000)	(2,510,300)	(2,548,000)
Operating Income	455,687	423,422	964,707	911,958
Interest Expense	(107,329)	(100,492)	(210,758)	(198,703)
Other Income/(Loss), Net	21,543	8,038	35,120	10,049
Net Income Attributable to Common Shareholders	230,749	203,649	490,207	447,803
Cash Flows Used for Investments in Plant			1,146,952	869,168
Assets	32,658,840		32,658,840		$ 32,053,173
Operating Segments [Member] | Electric Distribution [Member]
Segment Reporting Information [Line Items]
Operating Revenues	1,275,900	1,303,100	2,677,000	2,739,200
Depreciation and Amortization	(105,400)	(98,400)	(235,200)	(226,100)
Other Operating Expenses	(925,300)	(994,400)	(1,967,300)	(2,083,300)
Operating Income	245,200	210,300	474,500	429,800
Interest Expense	(49,400)	(47,600)	(97,600)	(95,600)
Other Income/(Loss), Net	2,500	6,300	7,400	6,300
Net Income Attributable to Common Shareholders	121,900	102,800	236,000	211,300
Cash Flows Used for Investments in Plant			515,000	362,000
Assets	18,663,700		18,663,700		18,367,500
Operating Segments [Member] | Natural Gas Distribution [Member]
Segment Reporting Information [Line Items]
Operating Revenues	186,000	180,400	589,600	523,000
Depreciation and Amortization	(17,900)	(16,800)	(39,600)	(32,700)
Other Operating Expenses	(150,000)	(141,100)	(439,600)	(374,500)
Operating Income	18,100	22,500	110,400	115,800
Interest Expense	(10,900)	(10,400)	(21,500)	(20,500)
Other Income/(Loss), Net	100	100	400	(200)
Net Income Attributable to Common Shareholders	4,500	8,000	55,300	58,900
Cash Flows Used for Investments in Plant			139,700	105,000
Assets	3,337,000		3,337,000		3,303,800
Operating Segments [Member] | Electric Transmission [Member]
Segment Reporting Information [Line Items]
Operating Revenues	324,600	302,500	641,500	585,800
Depreciation and Amortization	(51,400)	(45,600)	(102,000)	(90,700)
Other Operating Expenses	(94,900)	(82,500)	(184,800)	(155,500)
Operating Income	178,300	174,400	354,700	339,600
Interest Expense	(28,900)	(27,400)	(57,000)	(55,300)
Other Income/(Loss), Net	6,800	5,300	11,700	7,900
Net Income Attributable to Common Shareholders	96,400	92,500	190,600	178,200
Cash Flows Used for Investments in Plant			415,600	349,100
Assets	9,003,400		9,003,400		8,751,500
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	217,000	211,100	453,400	425,300
Depreciation and Amortization	(7,900)	(7,500)	(17,200)	(14,400)
Other Operating Expenses	(195,900)	(188,100)	(412,500)	(385,400)
Operating Income	13,200	15,500	23,700	25,500
Interest Expense	(21,600)	(16,600)	(41,300)	(30,700)
Other Income/(Loss), Net	257,600	219,000	586,500	524,400
Net Income Attributable to Common Shareholders	249,000	220,700	571,200	523,100
Cash Flows Used for Investments in Plant			76,700	53,100
Assets	14,657,100		14,657,100		14,493,100
Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(240,700)	(229,900)	(493,600)	(450,500)
Depreciation and Amortization	500	500	1,100	1,100
Other Operating Expenses	241,100	230,100	493,900	450,700
Operating Income	900	700	1,400	1,300
Interest Expense	3,500	1,500	6,600	3,400
Other Income/(Loss), Net	(245,500)	(222,600)	(570,900)	(528,400)
Net Income Attributable to Common Shareholders	(241,100)	$ (220,400)	(562,900)	(523,700)
Cash Flows Used for Investments in Plant			0	$ 0
Assets	$ (13,002,400)		$ (13,002,400)		$ (12,862,700)